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A Risk Analysis‐Best Worst Method Based Model for Selection of the Most Appropriate Contract Strategy for Onshore Drilling Projects in the Iranian Petroleum Industry

Construction Project Management Department, Faculty of Architecture, Khatam University, Tehran, Iran
School of Built Environment, Western Sydney University, Sydney, NSW 2751, Australia
Centre for Infrastructure Engineering, Western Sydney University, Sydney, NSW 2751, Australia
Construction Project Manager, Iran
Author to whom correspondence should be addressed.
Buildings 2021, 11(3), 97;
Submission received: 26 January 2021 / Revised: 22 February 2021 / Accepted: 25 February 2021 / Published: 5 March 2021


The pre-project planning phase has a significant impact on the achievement of project objectives because during this stage, major decisions including involving contract strategies are made with a high degree of uncertainty. Studies show that the contract type can play a unique role in the achievement of project success. On the other hand, drilling projects can be considered as one of the most critical types of projects in the petroleum industry. In this research, a novel risk based best-worst method (risk-BWM) is proposed for solving the issue of selecting the best contract strategy. A three level methodology was designed; firstly, the risk breakdown structure (RBS) of drilling projects was created in four levels including one heading in level 0, eight main areas of risk in level 1, 34 sub-areas of risk in level 2, and finally, 217 risk items in level 3. Secondly and on the basis of BWM, the weights of risk factors were determined as the selection criteria and consequently the best and the worst criteria were specified. Finally, using pair-wise comparisons between six types of drilling prevalent in contracts, the most appropriate contract type was proposed. The contribution of this study is the development of a generic RBS for drilling projects and application of the risk factors for the first time for the selection of contract type using the BWM method, which has the potential of being adapted for other types of underground projects.

1. Introduction

Drilling projects are very expensive efforts which provide high quality data or valuable products for all mineral searching operations [1]. They pinpoint and distinguish economic mineralization in nearly every case, which provides the true challenge for all the theories, concepts, and predictions developed in the previous phases of the searching process for prospect recognition and target generation [2]. Drilling technology is a distinctive field in which nearly all production is carried out underground [3]. One of the key phases of the upstream sector of onshore projects is drilling [4]. The upstream sector encompasses all phases of exploration, which include seismology and associated geological research, together with exploratory and descriptive drilling activities [5]. These types of projects require strategic planning to succeed, because many factors in different levels affect this section of the industry [6]. Therefore, the risk management and administration of uncertainties in these projects, for instance through contractual provisions, become more crucial [7]. The high risk of such activities is among the key elements of upstream onshore operations. However, there are no consistent models that define, classify, and prioritize drilling risks. Even though the risk registry is not accessible for drilling activities, there is a good likelihood that these approaches and databases will be kept by major oil firms as technical expertise. It is therefore essential to define and categorize, initially, the challenges underlying this sensitive and significant part of drilling related risk management. It is important to recognize the risks related to the activity in pre-contractual scenarios in which most of the contributing factors have not still been decided. Also, it is highly important to have an appropriate contract for efficient risk management between the contracting parties. Three main conventional drilling contract approaches have been discussed in this study: daily drilling, footage drilling, and turnkey drilling contracts. The most prevalent traditional drilling techniques in upstream oil reserves are these three types of contracts. Considering incentives as a powerful mechanism for achievement of the project objectives increases the potential contractual alternatives from three to six main strategies. However, the lack of investigations on novel contractual solutions, like smart contracts [8], has strongly hindered the whole industry. Getting a good contract becomes much more essential due to the high costs and time invested in onshore and drilling projects. When stakeholders encounter high expenses and multiple risks in these ventures, the value of a strong contract reveals itself, as it adds greatly to the efficiency of the projects, resolves conflicts, and minimizes disagreements. As such, in this analysis, an effective decision method of contract selection as a structured problem [9,10] is offered after considering the risk factors of the oil and gas drilling activity using the multi-criteria decision approach (BWM: best-worst method). The outcomes enable each corporation to obtain, according to its risk acceptance limit, the levels associated with the suggested method and choose the most effective contract structure. By explaining the roles and responsibilities, this approach will greatly reduce the expenses and time needed to finish a project. In the following sections of this paper, the types of drilling contracts and the risks in this industry are introduced and reviewed, the methodology of the study is described, and the proposed RBS, selection criteria weighting method, and contract selection process for an onshore project is illustrated. Finally, the multi-criteria decision making model for selection of the most appropriate drilling contract based on risk analysis is proposed.

2. Literature Review

2.1. Drilling Contracts

The drilling industry consists of five main markets as illustrated in Figure 1 and the drilling contractor is the central point in this context [6]. The upgrade market is related to maintenance and treatment activities; the secondhand market refers to transactions among contractors to sell and to buy equipment; the scrap market is a section where contractors connect to recycling specialized firms; the newbuilds market refers to the relation between the contractor and other firms willing to buy the contractor company. Although other main decisions including selection of the most qualified sources for the project have a significant impact on project success [11], the contract selection is still considered as the most important stage in the pre-project phase. The types of drilling agreements and the risks in this field are presented and examined below. Also, through considering risk assessments by employing multi-criteria decision-making methods, the most suitable drilling contract is recommended.
Drilling contracts are at the heart of the upstream operational deals. They take different forms and are negotiated to various levels based on the contract value, the level of risk, and the nature of criteria that could be determined by regional forms. The emphasis of this study is on the general conditions of common oil and gas contracts [12]. Three main forms of drilling agreements regulate the drilling of domestic oil and gas wells: footage, day-work, and turnkey. The day-work agreement traditionally is the most frequently used type [6], while in some places or during certain periods, the footage or turnkey based contracts could be utilized [13]. The major alterations between these three primarily relate to whether the risk is estimated and apportioned or not [14]. The incentive mechanisms can be combined to each of the above three contracts and on this basis, the possible forms of agreement increase to six alternatives. However, the incentive contractual mechanisms are described below separately.

2.1.1. Day-Rate Contracts

Among drilling agreements, one of them is the “day-rate” or “day-work” [15], which is by far the most functional and the most common type of drilling contracts [1]. Here, the contractor shall be charged a set amount (rate) for work produced by the drilling party over a full-day, with the contractor only accepting defined risks and the drilling party having most of the liabilities [13,16]. The sum of the specified day-rate depends on a variety of factors, like market conditions, the kind of rig, the number of people in the workforce and the team in charge of furnishing the workforce, the stage of operation, the specialization of the operation, the drill pipe, other machinery, and special services. The day-rate can vary at different points of project execution. Moreover, a day-rate contract can allow for lump-sum payments for specialized tasks, including deployment and layoffs [13,14]. Day-work contracts that are commonly used for drilling wells do not create a possibility for the contractor to make profits that could lead to a rise in efficiency or a reduction in well expenses [17]. Day charges operate on demand and supply dynamics in a way that, when demand for a rig goes beyond supply, day rates increase [11,18]. When demand for rigs, particularly those built for a specific purpose, like drilling of a deeper well is at its peak, the drilling operator might ask for a “term day-work” agreement. Within this form of contract, the provider is allowed to expect, for the duration of the contract, a certain day-rate, whether or not the rig is working, standing, or rigged and inactive [13]. A detailed drilling service is provided by the well operator to guide the contractor on how to move ahead with the well, including all the well supplies and any service needed for the well. To mine the well, the drilling contractor supplies drilling tools and staff [19]. Providers have a delegate at the project location. Like management at the rig, the payment system is basically a provider process [16]. Day-work contracts offer a degree of leeway for the provider to modify the work order. At the same time, the contractor would not be given a motivation plan to finish the job more efficiently and at a low cost. Thus, opposed to the primary estimate, there seems to be an inclination to raise costs and time [20]. The drilling party is accountable for the defined risks under the day-rate contract, whereas the provider is accountable for the overall risk of delay or even for the risk of liability not borne by the contractor [13]. In such a deal, the contractor is just responsible for the risks of the machinery, services offered, and the supply of the workforce. All the remaining risks rest on the operator [3].

2.1.2. Footage Contracts

The footage drilling agreement is used in places where drilling expenses can be efficiently anticipated in onshore regions where multiple wells are drilled [21]. A footage contract offers the fixed price per foot for the hole drilled from the ground to the maximum depth or for any other task required to be paid to the drilling contractor [13]. Essentially, a “footage” contract stipulates that the drilling service provider supplies the drilling staff, the equipment, and certain defined services as well. In a footage contract, the provider undertakes more well-related risk compared to a day-rate contract that is adjusted by a slightly higher price to the operator. The value of such a deal increases if the contractor can drill more effectively than expected. However, if the well faces problems and requires more for each well drilled per foot, then the drilling party pays the extra cost and can lose money [14]. Since the drilling party is compensated just for footage drilled and the specified day-rate, and since it takes on more risk, a footage agreement is considered to be more beneficial to the operator compared to a day-work agreement [13]. Footage deals are mostly considered for the area above the potential reservoir where, from an assessment or processing perspective, hole factors are less important [4].

2.1.3. Turnkey Contracts

A “turnkey” agreement allows for a fixed price to be given to the drilling party to drill a well to a required depth or identified formation [13]. This price concerns the supply by the drilling party of all services, such as the workforce, drilling rigs, machinery, equipment, and particular services. Once the operation is completed, the negotiated amount can be reimbursed and the well is dug to a specific depth (Contract Depth) [22]. The complication with this plan is making sure that the company is provided with a “quality well” because the drilling party wants to dig as quickly and frugally as possible. Thus, for each well, the drilling party should ensure there is an agreed objective quality level. The assurance must determine remedial steps to be carried out if a substandard well is delivered [4]. For the drilling party, a pure turnkey agreement offers the highest risk as well as the highest reward. With this type of agreement, for a lumpsum, set price, a drilling contractor is obliged to drill the well completely. The drilling contractor covers all the expenses and risks of the work and makes contracts for machinery and services with third parties. Therefore, to minimize the risk ingrained in drilling wells, operators choose turnkey contracts [14]. Since the drilling party assumes all risks, the actual anticipation of the “cost” of the well must be increased to reduce such risks. The potential cost of these risks is applied to the projected real cost, and the profit margin, to achieve a turnkey bid price [21].

2.1.4. Incentive Contracts

Conventionally, incentive agreements (sometimes referred to as “risk contracts”) are based on footage or turnkey ideas in the drilling sector [23]. Today, however, despite the form of agreement used, steps have been taken to guarantee that the arrangement between the parties provides motivations in line with the conditions of each contract. Incentive agreements are a way of forming a connection between the sums charged and the efficacy of the services provided by the operator. In this type of contracts, objectives are established based on capability standards. The costs of services are then changed based on the achievement of the intended targets. The productivity-based price change is an efficient way to attract contractors. Therefore, accomplishing the drilling objectives results in rewarding the contractor, and failure to deliver them will lead to a fine [24]. Recently, this approach of engaging in drilling activities has been implemented very efficiently and has led to a considerable reduction in expenses. Different systems are in deployment, generally offering a bonus for greater productivity than average. The contractor is in accord with the company on the requirements for the well. Thus, the ′historic′ cost is delineated for similar wells that have been drilled already. This enables the projected cost of the new well to be calculated. The drilling party will be solely responsible for digging the well, and the company and the contractor will divide the cost savings obtained.

2.2. Risk Analysis of Drilling Projects

Risk can be defined in various ways. The established outlooks and meanings of risk are centered on probabilities [25]. PMBOK (2018) describes risk as any “uncertain event or condition that, if it occurs, has a positive or negative effect, such as time, cost, scope or quality, on at least one project objective.” Wideman (1992) describes project risk as “the cumulative effect of the chances of uncertainty occurrences adversely affecting project objectives” [26]. Some more risk definitions are as follows: Risk is a way of measuring the possibility and severity of undesirable reactions [27]; Risk is a combination of the possibility of a situation and its repercussions [28]. As long as they are in step with the benefits, certain risks should be considered. Risks pose threats to the progress of ventures. It has been shown that failure to properly manage risks causes time and cost overruns in activities [29]. For all these concepts, what is similar is that events (initiating incidents, scenarios), consequences (results), and probabilities are included in the definition of risk. Uncertainties are stated through probabilities [25]. It is worth mentioning that there are theoretical differences between application of the risk and the uncertainty concepts; whereas risk refers to circumstances where the possible consequences and their probabilities are determinable for the decision-maker, uncertainty is used for situations that the probability and impact of occurrences are completely unknown [30,31].

2.2.1. Risks of Contract

The term ′risk allocation′ is widely used to define responsibilities. The distribution of responsibilities among each of the parties to the contract is a basic component of contract terms. There is a hypothesis that responsibilities should be assigned based on who is in the right position to manage risks or for whom those risks are economically feasible. It may be argued that the exercise of obligation distribution should be done in the most balanced way. It seems that the client should assume those liabilities and risks, which really are under the command of the client and the contractor should assume the liabilities and risks that are under the command of the contractor.

2.2.2. Risk Management in Drilling Process

Drilling is a strategic and vital activity, featuring practices that are dynamic and dangerous in resource exploration [32]. A danger is any unscheduled event (risk) or incident likely to cause a drilling process to diverge from its predefined strategy or critical path [33]. These unplanned incidents give rise to events ranging from unproductive drilling time or marginal impacts on the drilling (small amounts of fluid wasted) to serious wellbore malfunctions and a lack of command in the drilling process. It is also described as “trouble.” Not only geological uncertainty, but also mechanical issues or human errors are the results of these incidents. Finally, the drilling schedule, budget, project completion, and credibility of the companies concerned will be impacted by these disruptions [34]. More updated information surfaces when the drilling starts and some expected hazards may still cause harm, whereas others may not. It is possible to discover and identify new hazardous situations, and the nature of those that are already known may change. Risk management should also be planned out at all levels of the project regularly, that is before, during, or after drilling [35]. Of the most significant elements of setting up subsurface geology in engineering projects is the management of drilling hazards. Drilling risks resulting from geological uncertainties, technical problems, environmental extremes [36,37], or human error have been reported at coastal and terrestrial sites [33]. A Risk management process includes the procedures for the preparation, assessment, review, response planning, implementation of responses, and control of the risk of the work [38]. The primary goal is to define and monitor the most relevant risks [39]. The most critical hazards in the drilling sector must therefore be identified [29]. Either internal or external risks threaten drilling programs. All the risks could hurt the project′s budget, schedule, or efficiency. Risk management should therefore be well understood and managed as an interconnected project management feature [40].

3. Research Methodology

To achieve the research′s objectives including: 1. Recognition of the main risks of drilling projects in Iranian onshore oil fields, 2. Ranking identified risks, and 3. Selection of the most appropriate drilling contract based on risk analysis, a three levels methodology was created. In the first step, to recognize the uncertainties and challenges of drilling projects in a hierarchical manner, a questionnaire was designed in a closed format. In this questionnaire, data relating to risks in drilling projects were gathered and subsequently organized into a proposed structure. The experts were asked to add, amend, or delete items as required, reaching consensus among experts towards the end of the process. The input of the first stage was a basic structured data of disputes extracted from the literature review and the output was the risk breakdown structure (RBS) of drilling projects. We explained that in reviewing the available resources, the researchers were looking for items that have been introduced in previous references as possible and probable risk parameters affecting drilling projects that, if they occur, affect one of the predetermined objectives. These sources are listed in the presented table in the Appendix A. The second questionnaire was designed to obtain the experts′ judgments about the risks occurrence probability and their prospective impact on the project objectives. The key project objectives including cost, time, quality, environment, and safety were adopted in this regard. The input of this stage was the RBS and the output was the estimation of probability and impact assessment of the recognized risks. On the basis of the above quantitative analysis using the opinion of the experts, 35 of the most effective risks were selected for applying in a project contract strategy selection model. Finally, the experts were asked to assess the appropriateness of contract alternatives against the selected risks, and then the most appropriate contract strategy was proposed based on the BWM method. Since there is no reliable database which has organized and has assessed the risks of drilling projects, acquiring the experts′ opinions was considered as the most reliable method and therefore all above data gathering procedures were programmed in a Delphi process. In this regard, a two round Delphi technique (for each stage) with a panel including eight experts who had one of the following three characteristics were considered:
  • At least eight years’ experience in management of drilling contracts; or
  • At least 10 years’ experience in academic research on drilling contracts; or
  • At least having a master’s degree in petroleum project management.
  • The research methodology and its elements are shown in Figure 2.
The Best Worst Method (BWM) is a multi-criteria decision-making method developed by Jafar Rezaei [41]. In order to identify the weights of parameters, BWM utilizes two sets of pairwise comparisons. It contrasts the best parameter with the other parameters and the worst parameter with all the other parameters. The objective was to find the optimum proportion of weights and consistency by means of a standard linear optimization model developed by a comparative system [42]. The BWM previously has been applied in a vast spectrum of research in the construction area such as the supplier selection [43,44,45], the contractor selection [46,47], site selection [48,49], and risk assessment [50,51]. Previous investigations demonstrate that the BWM method can lead to more consistent pair-wise comparisons and outcomes with higher reliability than conventional approaches. The Analytical Hierarchy Process (AHP) could be known as a multi decision-making strategy that can incorporate qualitative and quantitative variables in the overall assessment of alternatives [52,53]. It comprises three sections: the hierarchical structure, the pairwise comparative matrix, and the priority calculation method. The AHP evaluates the priority of any alternative to the overall objective of the issue of concern. At the peak of the hierarchy lies the ultimate target or the main objective. Subsequent lower levels then reflect a progressive dissolution of the alternatives to the problem. A decision-maker or a qualified party will perform a pairwise analysis of all the items at each point related to each of the project items at the higher step of the hierarchy. The pairwise analysis is founded on a range of 1–9, as described in Table 1 [54]. The formation of these decisions sets the criticality of the items at the lowest point (generally solution alternates) related to the achievement of the highest objective [53].

4. Data Analysis and Results

4.1. Risk Analysis to Develop the Selection Criteria

As discussed earlier, due to the lack of a coherent database of risks of drilling projects, despite the experience of hundreds of drilling projects in Iran and even a lack of access to such a bank internationally, the risks were first identified using the study of previous research and available technical documents. However, overall 217 risks were recognized: 122 items from the literature review and 95 items from the first stage of the methodology, including two rounds of the Delphi method. Therefore, in this process, a comprehensive list of potential risks of drilling contracts was formed and at the same time a categorizing procedure for rolling up the risks in a class was done. Thus, the output of this stage was the risk breakdown structure (RBS) of drilling projects of the petroleum industry as a generic list of potential uncertainties. The proposed RBS consists of one heading in level 0, eight main areas of risk in level 1, 34 sub-areas of risk in level 2, and finally 217 risk items in level 3. The comprehensive list of recognized risks in the form of RBS of drilling projects is shown in Appendix A. Figure 3 illustrates the four levels of the risk structure for organizational risks and organization related items.
Obviously, the importance of the recognized risks is not equal for all drilling projects and therefore, it was essential to rank them and to focus on the most effective items. In order to examine the prioritizing procedure of the potential risks, a real drilling project with the following eight features was selected:
  • Onshore project
  • Oil field with about 10 years production (brown field)
  • Sandstone formation with low porosity
  • Homogeneous formation without fracture
  • Drilling depth up to 100 m
  • Vertical drilling method
  • Available data of previous well drillings
  • Conventional access to the well drilling location.
Based on the experts′ opinions, the probability of risk occurrence and also their impacts on objectives of the defined project have been judged. Using the average of gathered data, the risk importance index (RII) was calculated based on the Equation (1):
R I I R i = 1 5 j = 1 5 P i I k j
where R I I R i indicates the risk importance index of risk R i on project objective k, k ∈ {cost,time,quality,environment,safety}, P i is the probability of occurrence of R i and I k j is the impact of risk R i on the project objective k . The higher value of RII presents an overall risk significance in the project parameters. Table 2 represents the top ranked risk importance index of drilling projects′ risks and impact of them on the five main project objectives including the cost, time, quality, safety, and environment. The cutting line for top risks was determined to be the minimum overall impact of 0.4 on project objectives based on the 35 high risks that have been identified. It should be mentioned that the cutting point have been applied on each of eight main areas, in order to build a more balanced list of high risks. Also, Table 3 summarizes the top 10 ranked risks which have the most impact on a specified project objective. Figure 4a shows the overall top ten most effective risks and Figure 4b, Figure 5 and Figure 6 demonstrate this index per each project objective.

4.2. Weighting of Identified Drilling Risks Using BWM Method

In the next step and to calculate the weight of each risk on project contract selection the BWM was adapted from [55] and was employed in accordance with the following procedure:
  • Considering the high importance risks as the set of decision criteria { R 1 , R 2 , , R n } by decision-makers.
  • Determining the best and the worst criteria to be used for the decision environment. This step generally is done by choosing the best and the worst criteria among the set of criteria identified in Step 1 from the perspective of decision-makers. The best criteria represent the most important criteria and the worst criteria are the least important criteria for the decision. This step in the current study has been completed in the previous stage and the importance of the criteria has been determined already. The Blow out contingency (R1) and the Changing social responsibility rules and regulations (R35) have been considered as the best criterion and the worst criterion, respectively.
  • Determining the preference of the best criteria over all the other criteria: A number between 1 and 9 (1: equally important, 9: extremely more important) is used to indicate this value. The resulting Best-to-Others vector would be as A B = ( a B 1 , a B 2 , , a B n ) , where a B j indicates the preference of criteria B (best criteria) over criteria j and a B B = 1 . Using the BWM questionnaire, experts were asked to compare R1 with each of the other criteria and to express their preference using a value between 1 and 9. Then, by calculating the geometric mean of the four questionnaires, aggregated Best-to-Others (BO) was constructed, as shown in Table 4.
  • Determining the preference of each of the other criteria over the worst criteria: A number between 1 and 9 was assigned to this case as well. The Others-to-Worst vector would be A w = ( a 1 w , a 2 w , , a n w ) T , where a j w indicates the preference of the criteria j over the worst criteria W and a w w = 1 . Similarly to the previous step, the experts were then asked to express their preferences of all other criteria over the least important criterion of R35. As in the previous step, a value between 1 and 9 was used to determine the preferences. Then, by calculating the geometric mean, the aggregated Others-to-Worst (OW) vector was constructed as shown in Table 5.
  • Find the optimal weights ( w 1 * , w 2 * , , w n * ) : Solving the problem (1) will result in the optimal weights for the criteria. To determine the optimal weights of the criteria, the maximum absolute differences | w B w j a B j | and | w j w w a j w | for all j should be minimized.
    min max j { | w B w j a Bj | , | w j w w a jw | } s . t . j w j = 1 w j 1 ,   f o r   a l l   j
This model can be solved by transferring it to the linear programming (2) [41]:
m i n   ξ s . t . | w B w j a B j | ξ   f o r   a l l   j | w j w w a j w | ξ   f o r   a l l   j j w j = 1 w j 0   ,   f o r   a l l   j
By solving this problem, the optimal weights ( w 1 * , w 2 * , , w n * ) and the optimal value of ξ * are obtained. ξ * can be defined as the consistency ratio of the comparison system. It means that the closer ξ * is to zero, the more consistent the comparison system is provided by the decision makers. The Equation (2) was used to check the consistency of the comparisons [56].
C o n s i s t e n c y   R a t i o = ξ * C o n s i s t e n c y   I n d e x .
The consistency index can be retrieved from Table 6. In this table, the lower the consistency ratio, the higher the reliability of the comparisons. As can be inferred from Table 2, in this case, “Blow out contingency”, “Tight hole of the well and casing run problems”, and “Pipe failure” are the most important drilling risks and “Disposal and discharge of wastewater and drilling fluid”, “Lack of sufficient knowledge and information of field and reservoir structures”, and “Changing social responsibility rules and regulations” are the least important drilling risks, respectively. As shown in Table 7, the comparisons show a high consistency as the value of consistency ratio of criteria is close to zero (the consistency ratio for criteria comparisons is 0.18).

4.3. Prioritize Contract Alternatives Using the AHP Method

The purpose of this paper was to propose a model for selecting the most appropriate drilling contract based on risk analysis. Therefore, three models of the most common contracts of the onshore drilling industry were selected through expert opinions. Day-rate contract, Footage contract, and Turnkey contract options were described in detail in the literature review. As discussed earlier, they can be combined with incentive mechanisms, therefore there are six different contract alternatives. Given the impact of risk on project objectives (cost, time, quality, safety and environment), these calculations were performed by looking at overall impacts. In order to prioritize these contracts, the AHP method was used, which is explained below.

4.3.1. Development of the AHP Model

The design of the AHP hierarchy must satisfy the goal of developing a model that will allow operators or contractors to decide which drilling contract is more appropriate for their particular situation. The hierarchy developed in this study consists of three levels. The top level represents the goal of selecting the best onshore drilling contract. The last level is represented by the six alternative drilling contracts. The second level is the decision criteria that include 35 drilling risks in this article.

4.3.2. Determining the Comparison Matrix

Once the hierarchy was established, the pairwise comparison evaluation took place. The use of this AHP model requires the expert′s judgment to discuss and determine the relative importance of each of the elements in the hierarchy. Each element in the third level (Drilling Contracts) was compared pair-wise with other elements at the same level, with respect to a criterion element. The pair-wise comparison was based on a scale of 1 to 9 as per the definition of weights given in Table 2. Table 8 shows a schematic matrix of pairwise comparisons of alternatives which was done for each criterion using Expert Choice software (V11.0, Expert Choice Inc., Arlington, USA).

4.4. Relative Weight and Priority Evaluation

According to the results of pair-wise comparisons and data entry in Expert Choice software, the relative weight of each contract for each criterion against the cost target was calculated. The crossing product of all project evaluations using all criteria determined the final priority for each contract in relation to the desired goal. The mechanism for calculating the final priority was to sum the products of the multiplication of each criterion′s priority weight by its alternative weight. The same process should be repeated for all six contracts. The final results for all contracts are shown in Table 9.

5. Discussion and Practical Implications

Construction contracts are one of the most crucial factors to address the challenging problem of risk management of a project. Hence project contract strategy and selection regarding the risks of a project can have a considerable impact on project success. Risks, which is defined as an uncertain event or condition that could occur, have an effect on project objectives [57], is an inevitable attribute of construction projects and actually the costs of them will be carried by the party who is determined to do so in the contract. The risks in construction projects can influence project key performance indices and basic objectives of time, cost, scope, and quality [58]. Project risk management has a significant impact on project performance because recognizing and handling the uncertainties majorly increases productivity in terms of cost, time, scope, quality, environment, and the other factors. Based on the proposed model in this research, impacts of risks on five different project objectives were assessed for selection of the most appropriate contract strategy. To this purpose, a WBM-based AHP system was developed in the context of the drilling projects. Firstly and based on a case, the recognized risks in the form of RBS were analyzed and the most effective (Blow out contingency (R1)) and the least effective (Changing social responsibility rules and regulations (R35)) ones were determined. These factors in the BWM were labeled as the best criterion and the worst criterion. However, based on a pair-wise comparison of available contract strategies as different alternatives, a “Footage Incentive” option was determined as the most appropriate contract strategy for drilling projects in Iran with the 8 dominant characteristics mentioned in Section 4.1. Reviewing the documents of the previous successful drilling projects in Iran, which have been implemented in the oil fields with the above mentioned features, shows that the results of the presented model, i.e., selection of the Incentive and Turnkey contract types, to an acceptable extent are consistent with the methods which are used in the industry. Since the presented RBS is a generic list of risks, the developed model can be adapted for contract selection of drilling projects in the oil or even gas fields with different characteristics. Therefore, the first party of drilling projects i.e., the client or her/his agent company can employ the presented systematic model to solve the project contract strategy selection problem. The main limitations of the current study were the lack of comprehensive references who address the risks of drilling projects and also the scientific approach for oil fields categorization and description of their contracts.

6. Conclusions

In this study, a novel approach has been introduced to solve the contract selection problem in the context of the drilling projects. The major contribution of this study can be divided into two parts: development of a generic list of prospective risks in a structured form named RBS. Also, proposing a risk-BWM Based model to solve the original problem of contract selection. Although the presented RBS has been developed for onshore drilling projects, it can be adapted for a wide range of underground drilling projects including offshore efforts and geothermal activities. The comprehensive RBS include four levels: one heading in level 0, eight main areas of risk in level 1, 34 sub-areas of risk in level 2, and finally 217 risk items in level 3. The above RBS have been formed in a bottom-up method; firstly the 122 relevant risks in previous research were gathered and then they were purified and completed using the Delphi method. In the next step, the recognized risks were ranked considering their impact on project objectives and finally they were used to solve the contract selection problem through BWM. However, converting the risk items into decision criteria through assessment of their probable impact on project objectives can open up new horizons in decision making area in the early phases. Therefore, a decision making model was proposed for the determination of a contract strategy which itself is considered as one of the most significant parameters that affects a project’s success. It is worth mentioning that it is crucial to select the most appropriate contract type in the pre-project planning phase, especially in drilling activities which are considered as high cost projects in the upstream sector of the petroleum industry.

Author Contributions

Conceptualization, A.F.; methodology, A.F., M.R., and S.P.; validation, A.F., M.R. and P.K.; investigation, A.F.; resources, P.K.; writing—original draft preparation, A.F.; writing—review and editing, A.F., P.K., and S.P.; supervision, M.R.; project administration, M.R. All authors have read and agreed to the published version of the manuscript.


This research received no internal or external funding from any commercial or non-commercial source.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

All data is contained within the article.

Conflicts of Interest

The authors declare no conflict of interest.

Appendix A

Table A1. Risk breakdown structure of drilling projects.
Table A1. Risk breakdown structure of drilling projects.
RBS Level 0RBS Level 1RBS Level 2RBS Level 3ReferencesRBS Code
Onshore Drilling RiskOrganizational/Managerial RiskOrganizationInadequate project organization Structure[40]1101
Change of organization ownership or management[59]1102
Improper project feasibility study[40]1103
Lack of proper data bank for accidents/ keeping the accident data secret[60]1104
Lack of sufficient resources to improve HSE[60]1105
ProjectBureaucratic government system and long project approval procedure[40]1201
Late internal approval process from the owner[40]1202
Unclear and imprecise delegation of responsibilities and roles and project charter[61]1203
Changes in the scope of the projectSurvey1204
Failure to achieve the main target point[62]1205
Lack of proper written work procedures and instructions[60]1206
PlanningWeakness in planning and scheduling and initial project resources[63]1301
Improper project planning and Budgeting and lack of accurate estimation of project value[40]1302
Lack of emergency response plan[60]1303
DesignPoor design[64]1401
Design changes[65]1402
Late changes to well design and procedures[35]1403
ImplementationInappropriate choice of project implementation method[62]1501
Failure to predict the exact time to run the project[62]1502
Failure to select the type of implementation or project contract according to the conditionsSurvey1503
Project teamIncompetence of project team[40]1601
Inefficiency or inexperience of the project team 1602
Contractor′s error[66]1603
Making the wrong decisionsSurvey1604
Inefficient and poor performance of Constructors[40]1605
Excessive delays due to late decisions making by project participantsSurvey1606
ManagementIncompetence of project manager[67]1701
Lack of meritocracy (in recruiting, organizing and promoting staff)[60]1702
Incompetence of managers, supervisors and HSE crew[60]1703
Lack of support from executives and senior managementSurvey174
Human elementLack of skills of drilling staff (inadequate practice of skills)[68]1801
Lack of effective trainings[32]1802
There is poor relationship between personnel and superiors[32]1803
Inexperienced and less knowledgeable personnel[59]1804
Unmotivated personnel[3]1805
High stress and work pressure[68]1806
The number of workers in workplace is not appropriate for the job (more or less)[32]1807
The worker is injured or sick (temporarily, e.g., because of a flu)[32]1808
Ergonomic problems due to fatigue and pressure of non-stop activities[62]1809
Inadequacy of specialized personnelSurvey1810
Contractual RiskContractInappropriate contractsSurvey2101
Ambiguous conditions of contract[40]2102
Improper verification of contract documents[3]2103
Work conditions deferring from contract[40]2104
Changes on scope of contract[59]2105
Unballance share of legal risks between the partiesSurvey2106
Contractual liability failureSurvey2107
Type and terms of contractUnclear Contractual requirementsSurvey2201
Changes in contract related rules and regulationsSurvey2202
Economic RiskEconomic Changes and fluctuationsChanges in supply and demand[63]3101
Changes in tax policy and tax rates[63]3102
Oil price fluctuations[65]3103
Exchange rate changes[40]3104
Interest rate fluctuation[40]3105
Inflation rate fluctuation[40]3106
Instability of economic indicators of the host countrySurvey3107
Increase of material cost[40]3108
Increase of labor cost[40]3109
Price instability of fuel and steel[3]3110
Financial riskDeficiency in Provide project fundsSurvey3201
Increase the cost of materials and personnelSurvey3202
Improper cost calculations for the investment[66]3203
Delayed disbursement of funds from financiers[3]3204
Lack of economic productionSurvey3205
Political / Social RiskGovernmentConfiscation and nationalizationSurvey4101
Change in contract provisions by the government[63]4103
Reduction in annual budget allocation by government[3]4104
Changes in foreign investment lawsSurvey4105
Customs restrictions or the export and import of goodsSurvey4106
Change in rules and regulations[67]4107
Loss incurred due to corruption and bribery[3]4108
The state of the host countryRebellionSurvey4201
Political instability of the host countrySurvey4204
Sanctions and special bansSurvey4205
Social HazardsSabotage measuresSurvey4301
Lack of acceptance in local communitiesSurvey4302
Changing social responsibility rules and regulationsSurvey4303
Negative attitude towards local oil and gas multinational companiesSurvey4304
Changes in consumer demandsSurvey4305
Workers′ strikesSurvey4306
Dispute with residents around site[40]4307
Geological RiskGeological structureGeological structure and complexity of the region[65]5101
Geological Faults and Structures[69]5102
Abnormal pressured zone[64]5103
Unexpected natural subsurface obstacles[62]5104
Man-made subsurface obstacles[62]5105
Geological informationLack of full knowledge of the fieldSurvey5201
Lack of sufficient knowledge and information of field and reservoir structuresSurvey5202
Lack of accurate information on the structure and volume of the reservoirSurvey5203
Lack of accurate information on the fluid properties of the tank and how it is distributed in the tankSurvey5204
FormationDifferent behavior of geological formations in different wellsSurvey5301
Displacement of formationsSurvey5302
Formation pressure[35]5303
Total/partial losses in formation layers[62]5304
Operational RiskWell casingLack of well rehabilitation before casing running operations and the resulting problemsSurvey6101
Problems with Reamer running into a well, such as Fishing or falling its rollersSurvey6102
Problem in Shoe and its installation and disruption in casing runningSurvey6103
Float Shoe plaque while casing runningSurvey6104
Damage to casing in the operational area, especially their threads due to incorrect transmission conditionsSurvey6105
Changes in the size of the inner diameter of the casing in some parts due to impactSurvey6106
Lack of wrenches and tools suitable for casing runningSurvey6107
Centralizers break during casing and liner runningSurvey6108
Tight hole of the well and casing run problemsSurvey6109
Problems with not installing Cager Hanger properlySurvey6110
Liner Lap leak and perform Seal Nipple Packer operationSurvey6111
Seal Nipple Packer leak if usedSurvey6112
Casing corrosion and H2s migration to annulusSurvey6113
Casing Head Housing is not aligned for various reasons such as welding error and causing problems in the next phases of operation and installation BOPsSurvey6114
PipelinesPipe failure[70]6201
Corrosion thinning[70]6202
Defect of pipe[70]6203
Interference from the third party[70]6204
Incorrect operation[70]6205
Corrosion fatigue[70]6206
Unsuitable material[70]6207
Blocking of the drilling pipe or product pipe installation due to the swelling of clay and silt[66]6208
Sudden shock to the lines and the possibility of bursting pipes and fittingsSurvey6209
Lack of a needle valve to relieve pressureSurvey6210
Faulty pipe connections: the improper fusion/welding of pipes[62]6211
Inappropriate selection of external tube coating[62]6212
Tight hole stuck pipe[69]6213
CementingCementing of long casing strings[35]6301
Increase the well cavity and cementing problems[62]6302
Problems in casing cementing and Staying cement in casingSurvey6303
Improper quality of cement slurrySurvey6304
Error in the amount of material added to the cement[71]6305
Contamination of cement liquid with drilling mud or other caustic fluids[71]6306
Error in choosing the type of cement class[71]6307
Error in measuring the correct weight of cement[71]6308
Cement Shrinkage[71]6309
Insufficient drilling mud to replace cement inside the casing[71]6310
Error in calculating the amount of cement required for the pipe[71]6311
Non-compliance of cement program with operations and wells as a result of not performing the required tests correctlySurvey6312
Plugging the route of cementing during operationSurvey6313
Leakage of the route of cementing during operationSurvey6314
Loss of circulationFormations that are inherently fractured, cavernous, or have high permeability[69]6401
Highly fractured formations[72]6402
Drilling MudInfiltration of mud into wellsSurvey6501
Insufficient mud weight[73]6502
Not testing the mud properties[62]6503
Not testing water for the drilling fluid preparation[62]6504
Drilling fluid seepage[66]6505
Blow out contingencyFacing the high pressure layer in the drilling formation[71]6601
Plug annulus[71]6602
Annular Loss[71]6603
Temperature effects on drilling fluid[71]6604
Cut Mud[71]6605
Error in density measuring equipment[71]6606
Operator error in mixing the correct drilling fluid density[71]6607
Improper casing running[71]6608
Error inspecting Casing[71]6609
Error inspecting Cementing[71]6610
Wellbore instabilityCollapsing formation[74]6701
Mechanical failure by in-situ stresses[69]6702
Erosion caused by fluid circulation[69]6703
Chemical caused by interaction of borehole fluid with the formation[69]6704
Wellbore shrinkage[75]6705
EquipmentCorrosion or wear of mechanical parts[60]6801
Effect of Ageing; wear and tear, worn or fatigued part[35]6802
Equipment quality (special equipment; delay; damaged)[35]6803
Inadequate equipment for more high-tech production[63]6804
Inadequate equipment with type of operationSurvey6805
Poor maintenance program[60]6806
Operational and resource limits[35]6807
Material suitability and defects; Fabrication defects[35]6808
Equipment Failure[75]6809
Equipment failure due to H2S gas[62]6810
TechnologyNew technology (e.g., packers and liner hangers)[35]6901
Immaturity of new technology[61]6902
Complex technologiesSurvey6903
Lack of access to new technologies in geophysics and earth sciencesSurvey6904
Risk of changes in upstream technologySurvey6905
HSE Risk—Health and SafetyDrilling operationStart of drilling, Increasing pressure and cracking high-pressure lines of drilling fluid, colliding lines with peopleSurvey7101
Casing running, Falling suspended loads, work at heights, fatal falls, Stuck organs, collisions of pipes with people, collisions of elevators with the position of casing derrick manSurvey7102
Perforation, Falling suspended load, ergonomic damage, risk of employees falling from a height, hitting hammers on people, cracking of lines under pressure, explosion due to impact and electric current and lightning strikeSurvey7103
Acidizing, Cracking of lines and hitting people, Acid spraying and severe acid burns, skeletal injuriesSurvey7104
Cementing, Equipment damage, ergonomic discomfort, hearing problems, engine heat, heat stress, working with pressurized lines, tearing or cracking of lines, dust, falling and collision of equipment with peopleSurvey7105
Air drilling, Cracking of lines and hitting people, Abnormal and unusual noiseSurvey7106
Underbalanced drilling, Hitting the plexus, ergonomic injuries, working at height and risk of falling from a height, hitting joints, shifting load, risk of falling loadSurvey7107
Well Logging, Stuck of body parts, skeletal and muscular injuries, ergonomic injuries, noise, falling of equipment, collision of a tube stand with the position of the derrick man and damage to the position of the derrick manSurvey7108
Drilling equipmentDrilling rig installation, Stuck body parts between equipment, risk of falling load, falling from a heightSurvey7201
Capsule storage, Sudden explosion of cylinders during displacement of toxic and combustible gas leaks, fireSurvey7202
Power supply device, Fire, stuck of organs inside machines and amputation, electrocution, burns caused by electric shockSurvey7203
Raise BOP, Work at height and risk of fatal fall, Risk of falling suspended loadsSurvey7204
Coiled Tubing, Ergonomic injuries, collisions and damage to equipment and people, risk of falling, working with air lifts, working with pressure lines, cracking lines, spraying acid or diesel on people, skeletal and muscular injuriesSurvey7205
BOP Test, Slipping, Infiltration of mud and fluids into people′s eyes, falling into mud pit, Work at height, Failure to operate safety valves for drilling mud pumps, cracking of pressure lines, Elevators collide with peopleSurvey7206
HSE Risk—EnvironmentDrilling operationGroundwater contamination[76]8101
Surface water contamination[76]8102
Releases to air (local air quality)[77]8103
Releases to air (contribution to global warming)[77]8104
Visual impact[76]8105
Biodiversity impacts[76]8106
Land take[76]8107
Drilling fluid dischargeSoil pollution by drilling fluidSurvey8201
Groundwater pollution by drilling fluidSurvey8202
Adverse effects on wildlifeSurvey8203
Disposal and discharge of wastewaterSoil pollution by wastewaterSurvey8301
Visual impact in case of discharge to water resourcesSurvey8302
Water pollution by wastewaterSurvey8303
Unpleasant odor emissions into the environmentSurvey8304
Acid depositionSoil pollution by acidSurvey8401
Air pollution caused by acid vaporsSurvey8402
Unpleasant odor of acidSurvey8403
Groundwater pollution by acidSurvey8404
Oil and gas leaks, toxic gas leaks, waste or other environmental pollutantsReduction of biodiversity of organisms due to biological accumulation of hydrocarbonsSurvey8501
Damage to birds due to ingestion of petroleum productsSurvey8502
Biological accumulation of petroleum substances in the body of organismsSurvey8503
Chronic effects for humansSurvey8504
Hypothermia and death of mammals/birdsSurvey8505
Fire and damage to equipmentSurvey8506
Air pollution by gasSurvey8508


  1. Romagnoli, R.; Alkychyyev, D. Innovative Drilling and Completion Technologies. Ph.D. Thesis, Politecnico di Torino, Turin, Italy, 2020. [Google Scholar]
  2. Marjoribanks, R. Drilling: A General Discussion the Importance of Drilling. In Geological Methods in Mineral Exploration and Mining; Springer: Berlin/Heidelberg, Germany, 2010; pp. 75–84. [Google Scholar]
  3. Okwiri, L.A. Risk Assessment and Risk Modelling in Geothermal Drilling. Master’s Thesis, Iceland School of Energy, Reykjavík, Iceland, 2017. [Google Scholar]
  4. Jahn, F.; Cook, M.; Graham, M. Hydrocarbon Exploration and Production; Elsevier: Amsterdam, The Netherlands, 2008; ISBN 0080568831. [Google Scholar]
  5. Devereux, S. Drilling Technology in Nontechnical Language; PennWell Books: Tulsa, OK, USA, 1999; ISBN 0878147624. [Google Scholar]
  6. Schanche, L.E.; Steffensen, E.E. Valuation of Maersk Drilling. Master′s Thesis, Copenhagen Business School, Frederiksberg, Denmark, 2020. [Google Scholar]
  7. Stewart, A.M.Y.E. Indemnification and Insurance: Contractual Risk Transfer Provisions. Amystewartlaw 2020, 1, 5. [Google Scholar]
  8. Faraji, A. Smart Contract Based Conceptual Model for Optimizing Risk Distribution in Construction Industry. In Proceedings of the 3rd International Conference on Applied Researches in Structual Engineering and Construction Management, Chicago, IL, USA, 20–25 May 2019. [Google Scholar]
  9. Rahman, S.; Odeyinka, H.; Perera, S.; Bi, Y. Product-cost modelling approach for the development of a decision support system for optimal roofing material selection. Expert Syst. Appl. 2012, 39, 6857–6871. [Google Scholar] [CrossRef]
  10. Mohammadi, M. Maria Rashidi, Maryam Ghodrat, Bijan Samali and. Manag. Inf. Syst. 2018, 19, 22. [Google Scholar]
  11. Faraji, A.; Rashidi, M.; Sorooshnia, E. An Integrated Organizational System for Project Source Selection in the Major Iranian Construction Companies. Buildings 2020, 10, 251. [Google Scholar] [CrossRef]
  12. Marietta, K.; White, M. Drilling Contracts: Avoiding Misunderstanding. Energy Newsl. 2015, 1, 7. [Google Scholar]
  13. Anderson, O.L. The anatomy of an oil and gas drilling contract. Tulsa LJ 1989, 25, 359. [Google Scholar]
  14. Brown, L.B.; Flanagan, H.J. Onshore Drilling Contracts: Avoiding the Pitfalls of Form Drilling Contracts; Rocky Mountain Mineral Law Foundation: Westminster, CO, USA, 2004. [Google Scholar]
  15. Ottinger, P.S. Drilling Contracts. Ann. Inst. Min. L 1992, 38, 99. [Google Scholar]
  16. Caraballo, C.H.; Bastidas, G.E.; Torres, A.J. Experiences On New Types Of Drilling Contracts. In Proceedings of the IADC/SPE Drilling Conference, Dallas, TX, USA, 3–6 March 1998; Society of Petroleum Engineers: Richardson, TX, USA, 1998. [Google Scholar]
  17. De Wardt, J.D.P. Drilling in the Twilight Zone: Somewhere Between Dayrate and Turnkey. In Proceedings of the SPE/IADC Drilling Conference, Amsterdam, The Netherlands, 22–25 February 1993; Society of Petroleum Engineers: Richardson, TX, USA, 1993. [Google Scholar]
  18. Kaiser, M.J.; Snyder, B. A Primer on the Offshore Contract Drilling Industry. Ocean Dev. Int. Law 2013, 44, 287–314. [Google Scholar] [CrossRef]
  19. Miyora, T.O. Modelling and Optimization of Geothermal Drilling Parameters: A Case Study of Well MW-17 in Menengai, Kenya; United Nations University: Tokyo, Japan, 2014; ISBN 9979683449. [Google Scholar]
  20. Bret-Rouzaut, N.; Favennec, J.-P. Oil and Gas Exploration and Production: Reserves, Costs, Contracts; Editions Technip: Paris, France, 2011; ISBN 2710809753. [Google Scholar]
  21. Oeffner, J.A. New type of drilling contract minimizes well costs by guaranteeing performance. J. Pet. Technol. 1988, 40, 363–371. [Google Scholar]
  22. Kaiser, M.J.; Snyder, B.; Pulsipher, A.G. Offshore Drilling Industry and Rig Construction Market in the Gulf of Mexico; UBureau of Ocean Energy Management, Gulf of Mexico OCS Region: Washington, DC, USA, 2013. [Google Scholar]
  23. Moomjian, C.A., Jr. Incentive drilling contracts: A logical approach for enhancement of drilling efficiency. SPE Drill. Eng. 1992, 7, 9–14. [Google Scholar] [CrossRef]
  24. Jennings, A. Oil and Gas Exploration Contracts; Sweet & Maxwell: London, UK, 2002; ISBN 0421829206. [Google Scholar]
  25. Aven, T. On how to define, understand and describe risk. Reliab. Eng. Syst. Saf. 2010, 95, 623–631. [Google Scholar] [CrossRef]
  26. Wideman, R.M. Project and Program Risk Management: A Guide to Managing Project Risks and Opportunities. Ph.D. Thesis, Univerza v Ljubljani, Ljubljana, Slovenia, 1992. [Google Scholar]
  27. Lowrance, W.W. Of Acceptable Risk: Science and the Determination of Safety; William Kaufmann, Inc.: Los Altos, CA, USA, 1976. [Google Scholar]
  28. Guide 73: 2002: Risk Management Vocabulary Guidelines for use in standards. Int. Conf. Risk Assess. Manag. 2002, 24, 25.
  29. El-Sayegh, S.M. Risk assessment and allocation in the UAE construction industry. Int. J. Proj. Manag. 2008, 26, 431–438. [Google Scholar] [CrossRef]
  30. Aven, T. An emerging new risk analysis science: Foundations and implications. Risk Anal. 2018, 38, 876–888. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  31. Nesticò, A.; He, S.; De Mare, G.; Benintendi, R.; Maselli, G. The ALARP principle in the Cost-Benefit analysis for the acceptability of investment risk. Sustainability 2018, 10, 4668. [Google Scholar] [CrossRef] [Green Version]
  32. Amir-Heidari, P.; Farahani, H.; Ebrahemzadih, M. Risk assessment of oil and gas well drilling activities in Iran–a case study: Human factors. Int. J. Occup. Saf. Ergon. 2015, 21, 276–283. [Google Scholar] [CrossRef]
  33. Pritchard, D.M. Drilling Hazards Management—Excellence in Drilling Performance Begins with Planning (Part 1 of DHM Series); Deepwater Horizon Study Group: Berkeley, CA, USA, 2010. [Google Scholar]
  34. Gala, D.M.; York, P.; Pritchard, D.M.; Rosenberg, S.M.; Dodson, J.K.; Utama, B. Drilling Hazard Mitigation Technologies Key in Eliminating Non-Productive Time in Challenging Wells. In Proceedings of the SPE Oil and Gas India Conference and Exhibition; Society of Petroleum Engineers, Mumbai, India, 9–11 January 2010. [Google Scholar]
  35. Yasseri, S. Drilling Risk Identification, Filtering, Ranking and Management. Int. J. Coast. Offshore Eng. 2017, 1, 17–26. [Google Scholar] [CrossRef] [Green Version]
  36. Saha, L.; Bauddh, K. Characteristics of mining spoiled and oil drilling sites and adverse impacts of these activities on the environment and human health. In Phytorestoration of Abandoned Mining and Oil Drilling Sites; Elsevier: Amsterdam, The Netherlands, 2021; pp. 87–101. [Google Scholar]
  37. Tewari, S.; Dwivedi, U.D.; Biswas, S. Intelligent Drilling of Oil and Gas Wells Using Response Surface Methodology and Artificial Bee Colony. Sustainability 2021, 13, 1664. [Google Scholar] [CrossRef]
  38. Edition, P.G. A Guide to the Project Management Body of Konwledge; Project Management Institute: Newtown Square, PA, USA, 2018. [Google Scholar]
  39. Barkley, B. Project Risk Management; McGraw Hill: New York, NY, USA, 2004; ISBN 007143691X. [Google Scholar]
  40. Van Thuyet, N.; Ogunlana, S.O.; Dey, P.K. Risk management in oil and gas construction projects in Vietnam. Int. J. Energy Sect. Manag. 2007, 1, 175–194. [Google Scholar] [CrossRef]
  41. Rezaei, J. Best-worst multi-criteria decision-making method: Some properties and a linear model. Omega 2016, 64, 126–130. [Google Scholar] [CrossRef]
  42. Rezaei, J.; Nispeling, T.; Sarkis, J.; Tavasszy, L. A supplier selection life cycle approach integrating traditional and environmental criteria using the best worst method. J. Clean. Prod. 2016, 135, 577–588. [Google Scholar] [CrossRef]
  43. Rezaei, J.; Wang, J.; Tavasszy, L. Linking supplier development to supplier segmentation using Best Worst Method. Expert Syst. Appl. 2015, 42, 9152–9164. [Google Scholar] [CrossRef]
  44. Javad, M.O.M.; Darvishi, M.; Javad, A.O.M. Green supplier selection for the steel industry using BWM and fuzzy TOPSIS: A case study of Khouzestan steel company. Sustain. Futur. 2020, 2, 100012. [Google Scholar] [CrossRef]
  45. Youssef, A.E. An Integrated MCDM Approach for Cloud Service Selection Based on TOPSIS and BWM. IEEE Access 2020, 8, 71851–71865. [Google Scholar] [CrossRef]
  46. Bonyani, A.; Alimohammadlou, M. A new approach for evaluating international EPC contractors in Iran’s energy sector. Int. J. Constr. Manag. 2020, 20, 775–782. [Google Scholar] [CrossRef]
  47. Hashemi, H.; Mousavi, S.M.; Zavadskas, E.K.; Chalekaee, A.; Turskis, Z. A new group decision model based on grey-intuitionistic fuzzy-ELECTRE and VIKOR for contractor assessment problem. Sustainability 2018, 10, 1635. [Google Scholar] [CrossRef] [Green Version]
  48. Maghsoodi, A.I.; Rasoulipanah, H.; López, L.M.; Liao, H.; Zavadskas, E.K. Integrating interval-valued multi-granular 2-tuple linguistic BWM-CODAS approach with target-based attributes: Site selection for a construction project. Comput. Ind. Eng. 2020, 139, 106147. [Google Scholar] [CrossRef]
  49. Stević, Ž.; Pamučar, D.; Subotić, M.; Antuchevičiene, J.; Zavadskas, E.K. The location selection for roundabout construction using Rough BWM-Rough WASPAS approach based on a new Rough Hamy aggregator. Sustainability 2018, 10, 2817. [Google Scholar] [CrossRef] [Green Version]
  50. Torabi, S.A.; Giahi, R.; Sahebjamnia, N. An enhanced risk assessment framework for business continuity management systems. Saf. Sci. 2016, 89, 201–218. [Google Scholar] [CrossRef]
  51. Chang, T.-W.; Lo, H.-W.; Chen, K.-Y.; Liou, J.J.H. A novel FMEA model based on rough BWM and rough TOPSIS-AL for risk assessment. Mathematics 2019, 7, 874. [Google Scholar] [CrossRef] [Green Version]
  52. Saaty, T.L. A scaling method for priorities in hierarchical structures. J. Math. Psychol. 1977, 15, 234–281. [Google Scholar] [CrossRef]
  53. Saaty, T.L. Decision Making for Leaders: The Analytic Hierarchy Process for Decisions in a Complex World; RWS Publications: Pittsburgh, PA, USA, 1990; ISBN 1888603135. [Google Scholar]
  54. Vargas, L.G. An overview of the analytic hierarchy process and its applications. Eur. J. Oper. Res. 1990, 48, 2–8. [Google Scholar] [CrossRef]
  55. Rezaei, J. Best-worst multi-criteria decision-making method. Omega 2015, 53, 49–57. [Google Scholar] [CrossRef]
  56. Rezaei, J.; Hemmes, A.; Tavasszy, L. Multi-criteria decision-making for complex bundling configurations in surface transportation of air freight. J. Air Transp. Manag. 2017, 61, 95–105. [Google Scholar] [CrossRef]
  57. PMBOK. A Guide to the Project Management Body of Knowledge (PMBOK® Guide), 6th ed.; Project Management Institute: Newtown Square, PA, USA, 2017; ISBN 9781628253900. [Google Scholar]
  58. Xiang, P.; Zhou, J.; Zhou, X.; Ye, K. Construction project risk management based on the view of asymmetric information. J. Constr. Eng. Manag. 2012, 138, 1303–1311. [Google Scholar] [CrossRef]
  59. Jones, M.S. Offshore and Onshore Drilling Contracts. Energy Symp. 2011, 1, 1–18. [Google Scholar]
  60. Amir-Heidari, P.; Maknoon, R.; Taheri, B.; Bazyari, M. Identification of strategies to reduce accidents and losses in drilling industry by comprehensive HSE risk assessment—A case study in Iranian drilling industry. J. Loss Prev. Process Ind. 2016, 44, 405–413. [Google Scholar] [CrossRef]
  61. Skogdalen, J.E.; Vinnem, J.E. Quantitative risk analysis of oil and gas drilling, using Deepwater Horizon as case study. Reliab. Eng. Syst. Saf. 2012, 100, 58–66. [Google Scholar] [CrossRef]
  62. Aboumasoudi, A.S.; Behvandi, O. Identification and ranking risks of horizontal directional drilling for oil & gas wells by using fuzzy analytic network process: A case study for Gachsaran oil field wells. J. Ind. Syst. Eng. 2019, 12, 46–60. [Google Scholar]
  63. Lenkova, O.V. Risk management of oil and gas company in terms of strategic transformations. Risk Manag. 2018, 39, 30. [Google Scholar]
  64. Abimbola, M.; Khan, F.; Khakzad, N. Dynamic safety risk analysis of offshore drilling. J. Loss Prev. Process Ind. 2014, 30, 74–85. [Google Scholar] [CrossRef]
  65. Yanting, Z.; Liyun, X. Research on Risk Management of Petroleum Operations. Energy Procedia 2011, 5, 2330–2334. [Google Scholar] [CrossRef] [Green Version]
  66. Gierczak, M. The quantitative risk assessment of MINI, MIDI and MAXI horizontal directional drilling projects applying fuzzy fault tree analysis. Tunn. Undergr. Sp. Technol. 2014, 43, 67–77. [Google Scholar] [CrossRef]
  67. Ketabchi, R.; Ghaeli, M. An application of fuzzy BWM for risk assessment in offshore oil projects. J. Proj. Manag. 2019, 4, 233–240. [Google Scholar] [CrossRef]
  68. Chan, M. Fatigue: The most critical accident risk in oil and gas construction. Constr. Manag. Econ. 2011, 29, 341–353. [Google Scholar] [CrossRef]
  69. Stumpf, A.J. Drilling Hazards. In Encyclopedia of Engineering Geology; Bobrowsky, P.T., Marker, B., Eds.; Springer International Publishing: Cham, Switzerland, 2018; pp. 244–248. ISBN 978-3-319-73568-9. [Google Scholar]
  70. Shahriar, A.; Sadiq, R.; Tesfamariam, S. Risk analysis for oil & gas pipelines: A sustainability assessment approach using fuzzy based bow-tie analysis. J. Loss Prev. Process Ind. 2012, 25, 505–523. [Google Scholar]
  71. Mirzaie Aliabadi, M.; Mohammadfam, I. Risk Assessment of Oil and Gas Exploration Well Blowout in Drilling Operations Using Bow Tie Analysis and Bayesian Network. J. Occup. Hyg. Eng. 2018, 4, 59–69. [Google Scholar]
  72. Lavrov, A. Lost Circulation: Mechanisms and Solutions; Gulf Professional Publishing: Houston, TX, USA, 2016; ISBN 0128039418. [Google Scholar]
  73. Abimbola, M.; Khan, F.; Khakzad, N.; Butt, S. Safety and risk analysis of managed pressure drilling operation using Bayesian network. Saf. Sci. 2015, 76, 133–144. [Google Scholar] [CrossRef]
  74. Saleem Qadir Tunio, S.; Abdul Haque Tunio, A.H.; Naveed Ahmed Ghirano, N. Is It Possible to Ignore Problems Rising During Vertical Drilling? A Review. Res. J. Appl. Sci. Eng. Technol. 2011, 3, 1331–1336. [Google Scholar]
  75. Zhang, L.; Wu, S.; Zheng, W.; Fan, J. A dynamic and quantitative risk assessment method with uncertainties for offshore managed pressure drilling phases. Saf. Sci. 2018, 104, 39–54. [Google Scholar] [CrossRef]
  76. Corden, C.; Whiting, R.; Luscombe, D.; Power, O.; Ma, A.; Price, J.; Sharman, M.; Shorthose, J. Study on the Assessment and Management of Environmental Impacts and Risks Resulting from the Exploration and Production of Hydrocarbons; Final Report; Publications Office of the European Union: Luxembourg, 2016. [Google Scholar]
  77. International Finance Corporation. Environmental, Health, and Safety Guidelines for Onshore Oil and Gas Development; International Finance Corporation: Washington, DC, USA, 2017; p. 47. [Google Scholar]
Figure 1. The five main markets of the drilling industry [6].
Figure 1. The five main markets of the drilling industry [6].
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Figure 2. Objectives, methods, and outputs in each stage of the research methodology.
Figure 2. Objectives, methods, and outputs in each stage of the research methodology.
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Figure 3. Hierarchical view of the proposed risk breakdown structure (RBS) for drilling projects (level 0, 1, 2, and 3 of branch 01).
Figure 3. Hierarchical view of the proposed risk breakdown structure (RBS) for drilling projects (level 0, 1, 2, and 3 of branch 01).
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Figure 4. (a) Overall top 19 most effective risks, (b) Top 10 risks for cost objective.
Figure 4. (a) Overall top 19 most effective risks, (b) Top 10 risks for cost objective.
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Figure 5. (a) Top 10 risks for time objective, (b) Top 10 risks for quality objective.
Figure 5. (a) Top 10 risks for time objective, (b) Top 10 risks for quality objective.
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Figure 6. (a) Top 10 risks for environment objective, (b) Top 10 risks for for safety objective.
Figure 6. (a) Top 10 risks for environment objective, (b) Top 10 risks for for safety objective.
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Table 1. The comparison scale of the Analytical Hierarchy Process (AHP) method.
Table 1. The comparison scale of the Analytical Hierarchy Process (AHP) method.
1Equal importance
3Weak importance of one over another
5Essential or strong importance
7Very strong importance
9Absolute importance
2, 4, 6, 8Intermediate values between the two adjacent judgments
Reciprocals of previous valuesIf factor “i” has one of the previously mentioned numbers assigned to it when compared to factor “j,” then j has the reciprocal value when compared with i
Table 2. The list of risks with the highest RII.
Table 2. The list of risks with the highest RII.
Risk CodeDescription of RiskRBS CodeProbabilityImpacts on Project ObjectivesRII
R1Blow out of project contingency 66010.555.2064.2504.3273.3314.0824.239
R2Tight hole of the well and casing run problems 61090.423.1982.7532.8082.4742.9392.834
R3Pipe failure 62010.453.8054.4183.1560.9531.7022.807
R4Changes in the size of the inner diameter of the casing in some parts due to impact61060.423.7363.8772.7001.9071.4212.728
R5Lack of well rehabilitation before casing running operations and the resulting problems61010.453.9883.6023.2331.3491.4002.714
R6Collapsing formation and wellbore instability 67010.453.6403.9613.4440.3620.9712.476
R7Poor design and late changes to well design and procedures 14030.464.1084.8752.8300.1240.2412.436
R8Loss of circulation 64010.423.6783.0333.0550.0690.9402.155
R9Sanctions and special bans42050.352.2352.5471.6600.8522.7822.015
R10Incompetence of project team 16010.353.5982.8063.1040.1330.1111.951
R11Equipment failure 68090.352.2622.7642.6810.7071.3371.950
R12Blocking of the drilling pipe or product pipe installation due to the swelling of clay and silt62080.393.6633.2742.3440.2370.1731.938
R13Exchange rate changes31040.352.4952.9972.0380.7331.1541.883
R14Weakness in planning and scheduling and initial project resources13010.312.0951.9982.2151.4801.5251.863
R15Infiltration of drilling mud into wells65010.322.4982.6071.5750.8000.4671.589
R16Excessive delays due to late decisions making by project participants16060.312.4132.7041.0710.4810.7811.490
R17Problems in casing cementing and Staying cement in casing63030.251.6531.6751.3250.8250.6911.234
R18Ambiguous conditions of contract21020.251.5201.8781.1830.6120.6931.177
R19Inappropriate choice of project implementation method15010.211.1291.4091.3830.3061.1521.076
R20Corrosion or wear of mechanical parts 68010.251.9531.4470.9810.1570.4721.002
R21Error in measuring the correct weight of cement63080.231.4451.3231.2690.6250.2900.990
R22Lack of skills of drilling staff (inadequate practice of skills)18010.231.4261.1991.1960.5150.5670.981
R23Work conditions deferring from contract 21040.161.1271.2940.8510.4430.7530.894
R24Change in rules and regulations 41070.221.4861.5380.7590.2700.1150.834
R25Improper cost calculations for the investment 32030.150.8180.7070.7151.0520.8340.825
R26Inadequate project organization structure 11010.211.5901.0590.6520.0890.5450.787
R27Unclear and imprecise delegation of responsibilities and roles and project charter 12030.161.0010.8910.6120.6150.7920.782
R28Change of organization ownership or management 11020.221.1051.1630.8470.0360.5470.739
R29Acidizing which causes cracking of lines and hitting people, acid spraying and severe acid burns71040.181.0831.0500.9470.0560.4600.719
R30New and complex technology (e.g., packers and liner hangers) 69010.160.9921.1040.6500.1050.6270.696
R31Geological structure and complexity of the region 51010.151.0110.8111.0350.1180.1070.616
R32Oil and gas leaks, toxic gas leaks, waste, or other environmental pollutants85010.141.0260.9290.3830.2810.4600.616
R33Disposal and discharge of wastewater and drilling fluid83010.150.7300.1440.0571.2130.0370.436
R34Lack of sufficient knowledge and information of field and reservoir structures52020.150.7660.0670.0101.2300.0720.429
R35Changing social responsibility rules and regulations43030.140.4400.6530.4850.1150.3360.406
Table 3. The top risks versus each objective of the drilling project.
Table 3. The top risks versus each objective of the drilling project.
Project ObjectiveRisk CodeDescription of the RiskRII
CostR1Blow out of project contingency5.206
R7Poor design and late changes to well design and procedures4.108
R5Pipe failure3.988
R3Tight hole of the well and casing run problems3.805
R4Loss of circulation3.736
R8Lack of well rehabilitation before casing running operations and the resulting problems3.678
R12Sanctions and special bans3.663
R6Changes in the size of the inner diameter of the casing in some parts due to impact3.640
R10Exchange rate changes3.598
R2Collapsing formation and wellbore instability3.198
TimeR7Poor design and late changes to well design and procedures4.875
R3Tight hole of the well and casing run problems4.418
R1Blow out of project contingency4.250
R6Changes in the size of the inner diameter of the casing in some parts due to impact3.961
R4Loss of circulation3.877
R5Pipe failure3.602
R12Sanctions and special bans3.274
R8Lack of well rehabilitation before casing running operations and the resulting problems3.033
R13Blocking of the drilling pipe or product pipe installation due to the swelling of clay and silt2.997
R10Exchange rate changes2.806
QualityR1Blow out contingency4.327
R6Changes in the size of the inner diameter of the casing in some parts due to impact3.444
R5Pipe failure3.233
R3Tight hole of the well and casing run problems3.156
R10Exchange rate changes3.104
R8Lack of well rehabilitation before casing running operations and the resulting problems3.055
R7Poor design and late changes to well design and procedures2.830
R2Collapsing formation and wellbore instability2.808
R4Loss of circulation2.700
R11Incompetence of project team2.681
EnvironmentR1Blow out contingency3.331
R2Collapsing formation and wellbore instability2.474
R4Loss of circulation1.907
R14Infiltration of drilling mud into wells1.480
R5Pipe failure1.349
R34Disposal and discharge of wastewater and drilling fluid1.230
R33Oil and gas leaks, toxic gas leaks, waste, or other environmental pollutants1.213
R25Acidizing which causes cracking of lines and hitting people, acid spraying, and severe acid burns1.052
R3Tight hole of the well and casing run problems0.953
R9Equipment Failure0.852
SafetyR1Blow out contingency4.082
R2Collapsing formation and wellbore instability2.939
R9Equipment Failure2.782
R3Tight hole of the well and casing run problems1.702
R14Infiltration of drilling mud into wells1.525
R4Loss of circulation1.421
R5Pipe failure1.400
R11Incompetence of project team1.337
R13Blocking of the drilling pipe or product pipe installation due to the swelling of clay and silt1.154
R19Lack of skills of drilling staff (inadequate practice of skills)1.152
Table 4. Criteria Best-to-Others (BO) Vector.
Table 4. Criteria Best-to-Others (BO) Vector.
Best Criterion.R1R2R3R4R5R6R7R8R9R10R11R12R13R14R15R16R17R18R19R20R21R22R23R24R25R26R27R28R29R30R31R32R33R34R35
Table 5. Criteria for Others-to-Worst (OW) Vector.
Table 5. Criteria for Others-to-Worst (OW) Vector.
Worst Criterion.R1R2R3R4R5R6R7R8R9R10R11R12R13R14R15R16R17R18R19R20R21R22R23R24R25R26R27R28R29R30R31R32R33R34R35
Table 6. Consistency index.
Table 6. Consistency index.
a B W 123456789
Consistency index0.000.441.001.632.303.003.734.475.23
Table 7. The risks′ weights.
Table 7. The risks′ weights.
ξ * 0.98356948
Consistency Ratio0.18
Table 8. Pair-wise comparison matrix for six alternatives.
Table 8. Pair-wise comparison matrix for six alternatives.
Pair-Wise Comparison Matrix for R1 CriterionDay-Rate (X1)Footage (X2)Turnkey (X3)Day-Rate Incentive (X4)Footage Incentive (X5)Turnkey Incentive (X6)
Day-rate (X1)1abcde
Footage (X2)1/afghij
Turnkey (X3)1/b1/g1klm
Day-rate Incentive (X4)1/c1/h1/k1no
Footage Incentive (X5)1/d1/i1/l1/n1p
Turnkey Incentive (X6)1/e1/j1/m1/o1/p1
Table 9. Priority results for the drilling contracts according to the drilling risks.
Table 9. Priority results for the drilling contracts according to the drilling risks.
Alternative Code.Contract TypeFinal Normalized Score
X4Day-rate Incentive0.69
X5Footage Incentive0.86
X6Turnkey Incentive0.78
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Faraji, A.; Rashidi, M.; Khadir, P.; Perera, S. A Risk Analysis‐Best Worst Method Based Model for Selection of the Most Appropriate Contract Strategy for Onshore Drilling Projects in the Iranian Petroleum Industry. Buildings 2021, 11, 97.

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Faraji A, Rashidi M, Khadir P, Perera S. A Risk Analysis‐Best Worst Method Based Model for Selection of the Most Appropriate Contract Strategy for Onshore Drilling Projects in the Iranian Petroleum Industry. Buildings. 2021; 11(3):97.

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Faraji, Amir, Maria Rashidi, Pegah Khadir, and Srinath Perera. 2021. "A Risk Analysis‐Best Worst Method Based Model for Selection of the Most Appropriate Contract Strategy for Onshore Drilling Projects in the Iranian Petroleum Industry" Buildings 11, no. 3: 97.

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