Multi-Criteria Decision Analysis for Sustainable Oil and Gas Infrastructure Decommissioning: A Systematic Review of Criteria Involved in the Process

Abstract

The decommissioning of oil and gas (O&G, hereafter) facilities presents complex challenges when addressing the diverse needs of stakeholders. By synthesizing information from previous Multi-Criteria Decision Analysis (MCDA, hereafter) studies on decommissioning projects, this study aims to do the following: (a) formulate a structured set of criteria adaptable to MCDA for both offshore and onshore O&G decommissioning, (b) identify and analyze the evolving trends and regional disparities in MCDA for decommissioning, and (c) explore current O&G onshore decommissioning procedures and map specific criteria to these processes. Following a systematic literature review approach, this study analyzed 63 references across four stages from 2006 to 2024 and identified 158 criteria. These criteria were consolidated into a framework of 22 factors across dimensions comprising technical, environmental, societal, financial, health and safety considerations, and additional concerns from stakeholders. This study observed a significant focus shift from technical aspects to environmental considerations in decommissioning practices from 2011 onwards, reflecting growing awareness of sustainability. It also revealed regional differences, such as the technical emphasis in the North Sea and environmental concerns in Australia. Furthermore, this study refined O&G onshore decommissioning procedures and identified criteria gaps for further research, particularly in societal impact regarding public resource availability, recreational opportunities, and operating company reputation. The study provides a robust foundation for the development of future MCDA frameworks tailored to O&G infrastructure decommissioning projects, thus supporting long-term environmental and social sustainability.

1. Introduction

Decommissioning is the final stage in the life-cycle of offshore oil and gas (O&G, hereafter) platforms, initiated when operations are no longer economically viable [1,2]. The decommissioning process primarily focuses on reversing the installation process, from well closure to seabed cleaning, while also adapting to specific challenges such as minimizing impacts on finances, human safety, and the environment [3,4,5]. Globally, around 2000 platforms are expected to be decommissioned by 2040 [4]. The decision to decommission an offshore O&G platform is influenced by various uncertainties such as hydrocarbon prices, maintenance costs, environmental load, and structural deterioration [6]. Facilities with annual revenues under $5 million are often deemed unfeasible due to excessive operational costs, including staff, maintenance, and logistics [7].

This complex and expensive process is governed by a robust framework of national and international laws and regulations to ensure environmental protection [8,9]. Multiple studies have acknowledged five dimensions that should be considered in preparing the installation decommissioning program, including technical, environmental, societal, financial, and health and safety concerns [10,11,12]. None of the dimensions in isolation should be considered decisive for defining the alternative [12]. Together, the required criteria, technologies, and equipment form a comprehensive system for the practical execution of decommissioning operations [5]. These same dimensions have previously been emphasized in other assessments and decisions about alternatives to the closure of an O&G production unit, such as scientific studies [1,13] and technical reports [10,11].

The study of O&G platform decommissioning encompasses a range of critical aspects. Mathematical models that support decision-making have been designed to navigate the complexities of this field [7,14]. Environmental considerations are also addressed, with studies focusing on the ecological impacts of decommissioning activities [15,16]. Furthermore, extensive analyses have been conducted to ensure the best decommissioning outcomes based on various criteria [17,18,19]. The effectiveness of decision support tools has also been reviewed to guide the decommissioning process [20]. Additionally, research into the ranking of different decommissioning alternatives provides insights into the prioritization of approaches and influences strategic decisions in the field [19].

Despite the existence of previous studies on criteria for O&G decommissioning, several practical challenges continue to confront current practices. First, the current criteria are not consolidated enough to meet the diverse needs and interests of various stakeholders. For instance, coastal property owners may prioritize unobstructed ocean views [1,17,21], while others may value recreational fishing, diving, and boating opportunities [4,12,22]. These criteria could influence the effectiveness and fairness of the outcomes during the decommissioning process, yet they are often overlooked. Multi-Criteria Decision Analysis (MCDA, hereafter) has been developed to address this issue by incorporating the varied perspectives of stakeholders such as governments and energy companies [1,17,18,23]. This approach ensures that decisions are scientifically robust and account for long-term environmental safety and the interests of marine users [5]. Another problem is the limited study of O&G onshore decommissioning practices. Most studies have predominantly focused on offshore decommissioning, highlighting its environmental, economic, and societal dimensions [1,2,4,5]. In contrast, the study of onshore decommissioning procedures is limited and lacks a systemic procedure to guide the practices [10,11,24]. It overlooks the unique challenges associated with onshore decommissioning, such as logistical complexities in remote areas and the necessity of coordinating with local regulations and community interests [24]. Furthermore, the criteria used in onshore decommissioning need further exploration to better address the specific requirements and impacts of O&G decommissioning projects.

Therefore, this study aims to develop a comprehensive framework adaptable to decommissioning both offshore and onshore O&G facilities. By synthesizing information from MCDA, it considers the diverse concerns of all stakeholders, ensuring decisions are scientifically robust and consider economic, environmental, and societal impacts comprehensively. Furthermore, this study delves deeper into evolving trends and regional variations in MCDA decommissioning practices. It also refines onshore decommissioning procedures and identifies specific criteria used in onshore decommissioning to capture the existing gaps. This will contribute to a more balanced, sustainable approach to decommissioning that aligns with global sustainable development goals and protects marine environments effectively.

The remainder of this study is structured as follows. Section 2 outlines the research method, including paper screening processes and a descriptive analysis of these articles. Section 3 identifies and groups multiple criteria for decommissioning O&G facilities. Section 4 interprets the findings and synthesizes outcomes. Finally, Section 5 presents the conclusions.

2. Research Methods

The systematic literature review is a critical study of a research theme, allowing the researcher to map and evaluate the research topic and specify the research question for a deeper understanding. The research procedure was developed using the adaptation of the method proposed by [25] and considered five steps, as shown in Figure 1.

Step 1. Formulating the problem for a research synthesis: the problem for the research synthesis is clearly defined and presented in the Section 1.

Step 2. Searching the literature: the literature search adheres to a predefined protocol, which details the methodical approach to sourcing relevant literature, as described below.

The papers related to the decommissioning of offshore O&G platforms were searched mainly from databases: Scopus, Web of Science, and Science Direct. The research was structured with a combination of the following keywords: “decommission* AND decision mak*”, “decommission* AND decision analysis”, “decommission* AND multi-criteria”. Studies published in English between 2006 and 2024 were analyzed, which are in journals like Science of the Total Environment, Marine Structures, Ocean and Coastal Management, and Journal of Environmental Management. It is important to note that the methodology also encompassed non-O&G decommissioning, which includes topics such as waste management and the decommissioning of nuclear facilities. These broad references enable a comprehensive analysis of decommissioning criteria across various scenarios.

The systematic screening process depicted in the flow diagram (Figure 2) commenced with 542 records sourced from databases, search engines, and various organizational websites. These records underwent a two-level relevance assessment—firstly, titles and abstracts were scrutinized, followed by a thorough review of full texts. An initial exclusion of 143 records due to language, date range, and article type specifications reduced the pool to 399 records for preliminary screening. This phase culminated in the exclusion of duplicates and non-relevant articles, leaving 78 records for in-depth full-text evaluation. The rigorous assessment at this stage resulted in the further exclusion of 15 records based on duplication and irrelevance, resulting in 63 relevant papers used in this research. Finally, each paper was analyzed, the relevant information was gathered, and the results were systematized.

Step 3. Identifying and grouping criteria: In this step, 158 third-level criteria that influence the decommissioning process of offshore O&G platforms have been identified in the literature, and these have been grouped into 22 secondary factors across 6 dimensions. It is later analyzed in Section 3 for the detailed framework construction.

Step 4. Statistical analysis: a descriptive analysis of the selected articles was performed regarding several aspects, such as research sources, distribution of references over time, study regions, whether the focus was onshore or offshore, and criteria dimensions, as depicted in the Sankey diagram (Figure 3).

Most of these references (n = 60) focus on O&G facility decommissioning, while a smaller portion (n = 3) examines general decommissioning practices for non-O&G facilities. The literature spans four stages from 2006 to 2024, indicating an evolving focus on decommissioning practices, with 2016–2020 and 2021–2024 being active periods. Geographically, the North Sea and USA-California regions are prominently featured in the review, reflecting their significant roles in decommissioning activities. The literature mainly discusses offshore facilities (53 citations), onshore facilities (3 citations), and both contexts (7 citations), which reflects a broader research spectrum that includes both offshore and onshore facilities. The primary decommissioning dimensions are environmental, technical, and financial, while also considering safety, social issues, and other concerns. It shows an emphasis on environmental and technical aspects that align with the industry’s focus on sustainable and efficient decommissioning strategies.

Step 5. Interpreting and outcomes synthesis: The main points presented in the literature on decommissioning offshore and onshore platforms were analyzed and discussed, including the evolving trends and regional disparities in MCDA for decommissioning. The analyses are detailed in Section 4. The concluding remarks are in Section 5.

3. Multiple Criteria for Oil and Gas Decommissioning

The selection criteria list is crucial in the decision-making process as it determines the basis for making informed decisions [4,23]. From these 63 relevant references, this study identified 158 criteria. The results show that implementation expenditures, health and safety of offshore decommissioning personnel, effects on commercial fisheries, safety risk to onshore personnel, and energy consumption are the top main criteria. These priorities underscore the need for balanced and responsible decommissioning practices that protect both ecological and human health.

This review refines the existing five decommissioning criteria dimensions, including technical, environmental, societal, financial, and health and safety concerns [10,11,12] to better align with the specific requirements of O&G practices. For instance, while exogenous events such as hurricanes impact project costs and planning [4], this study emphasizes their effects on personnel safety, thereby categorizing them under the health and safety dimension. Similarly, the impact of the trawling industry and the growth of overfishing are considered mainly in environmental terms [1,26,27]. In this study, they are analyzed for their financial implications on fisheries and placed within the financial dimension. Furthermore, although local house prices are viewed from a societal perspective [28], this study evaluates them from the perspective of economic incentives and challenges, thus incorporating them into the financial consideration dimension. These adjustments ensure a more targeted and relevant application of criteria to the evolving demands of decommissioning in the O&G field.

As O&G decommissioning evolves, additional concerns, such as the level of interest from proponents and the services provided by contractors, also need to be factored into the decision-making process [4,29]. These additional concerns are essential to align the decommissioning strategies with the current market dynamics and stakeholder expectations. As shown in Figure 4, the framework constructed for this purpose integrates criteria relevant to decommissioning derived from an extensive analysis of existing literature. This thorough review has led to the categorization of 158 criteria into 22 factors, spanning six dimensions, with additional concerns included. This comprehensive framework serves as a robust tool for stakeholders to better evaluate decommissioning decisions, providing a holistic view of the potential impacts and benefits. It facilitates informed decision-making by ensuring that all relevant aspects are considered, thereby optimizing outcomes and mitigating risks associated with the complex nature of decommissioning projects.

4. Interpreting and Outcomes Synthesis

This section mainly explores how decommissioning criteria have evolved across different time periods. It also examines the specific concerns and variations in decommissioning practices across different regions.

4.1. Identify Dimension Changes over Time

The analysis of O&G decommissioning practices from 2006 to 2024 underscores evolving trends, as shown in Figure 5. Financial considerations have been the consistent focus since 2006. This emphasis highlights the critical role of budgeting, cost management, and financial planning in ensuring the feasibility and success of decommissioning operations [17,18,30]. Between 2006 and 2010, technical considerations dominated the focus of decommissioning projects, with an initial emphasis on developing specialized tools and methods to manage complex offshore operations effectively [31,32]. From 2011 onwards, there was a notable shift towards environmental concerns, prioritizing the mitigation of ecological impacts on marine ecosystems [2,26,33]. From 2016 to 2024, there has been an increased emphasis on societal impacts, health and safety concerns, and stakeholder involvement [1,34]. This trend reflects a deeper recognition of the social implications, such as public ocean access, recreational fishing, boating, and diving opportunities, of decommissioning. It also reflects a heightened commitment to upholding stringent safety standards for all personnel involved.

4.1.1. 2006–2010: Establishing the Foundation

This early period in decommissioning research established a robust foundation that integrated technical, environmental, societal, and financial dimensions, laying the groundwork for subsequent advancements. The focus was on the technical aspect, and the research area was both offshore and onshore projects in regions such as the North Sea [31,35] and Thailand [32].

From 2006 to 2010, decommissioning research focused on establishing a robust technical foundation for O&G facilities dismantlement. This period marked an increased emphasis on developing sophisticated tools and methodologies to address the complex requirements of decommissioning operations. The industry prioritized technical aspects such as logistics, specialized cutting tools, structural integrity, and the technical feasibility of decommissioning operation activity [31,32,35,36,37,38]. This focus on technical innovation highlighted the necessity for advanced solutions that could safely manage the intricate processes involved in both offshore and onshore decommissioning. During this phase, environmental considerations also began to gain prominence, driven by a growing recognition of the ecological impacts associated with decommissioning activities. Key environmental concerns included atmospheric impacts related to greenhouse gas emissions, energy consumption, and marine ecosystem disturbances [32,35,36,37]. These concerns underscored the need for strategies that balanced technical efficiency with environmental stewardship. The research explored the direct and indirect economic impacts, such as the implementation expenditures, the effects on local industries, and employment opportunities [35,36,37]. Societal impact discussions revolved around improving public access and ensuring clear seabed scenery, reflecting an increasing awareness of social responsibilities tied to environmental practices [35]. Furthermore, health and safety concerns focused on safeguarding both offshore and onshore operational personnel, as well as safety risks to other users of the sea [31,35,36,37,38]. The period emphasized stakeholder engagement and recognized the need for inclusive and transparent decision-making processes [32,37].

4.1.2. 2011–2015: Diversification and Depth

From 2011 to 2015, the focus of O&G decommissioning research shifted towards environmental impact, reflecting a global trend towards sustainability. The theme of decommissioning was primarily about offshore facilities, and covered regions like Malaysia [39] and USA-California [17,18,22,40,41].

In this period, decommissioning research matured with significant advancements in offshore technologies and methodologies, marking a transition towards more complex and environmentally conscious decommissioning strategies. The environmental issues broadened to include a comprehensive analysis of benthic disturbance, energy consumption, contamination, and the potential for creating artificial reefs, highlighting the growing complexity of environmental considerations in decommissioning operations [17,18,41,42]. Zawawi et al. [39] and Bernstein [41] explored decision-making tools and frameworks for assessing the feasibility and value of alternative decommissioning methods, highlighting sophisticated approaches. Financial aspects continued to be a central theme, with discussions on costs related to personnel, material replacement, and the broader impacts on local industries such as commercial fishing [17,18,22,41]. Social implications also received increased attention, emphasizing the importance of public ocean access, clear seabed scenery, and opportunities for recreational activities [17,18,22]. Health and safety concerns were also addressed, with a focus on minimizing risks to decommissioning personnel and public safety issues like navigation hazards [17,42]. While additional stakeholder concerns were not explicitly stated during this period, it suggested a need for greater stakeholder involvement and evaluation of decommissioning practice constraints to take appropriate actions.

4.1.3. 2016–2020: Comprehensive Insights

Between 2016 and 2020, environmental impact was the most important consideration in O&G decommissioning projects. Throughout this period, the research on decommissioning was indicative of a trend toward integrating diverse considerations into comprehensive decision-support frameworks. The decommissioning studies focused on both offshore and onshore across various regions and countries, such as North Sea [15,20,43,44], USA-California [30,45,46,47], Brazil [48,49,50], Australia [51,52], Malaysia [19,26], Mexico [33,53], and Thailand [54].

Environmental impact remained a central focus, with studies extensively discussing the marine ecosystem’s health. The research addressed a variety of impacts, from fish productivity to benthic disturbances, emphasizing the importance of minimizing ecological damage and enhancing biodiversity through potential initiatives like artificial reefs [1,15,20,21,26,28,30,33,43,44,45,46,50,52,53,54,55]. Technical aspects were rigorously evaluated, with studies concentrating on operational equipment and platform integrity. The research focused on elements like weight management, logistics, and diving equipment, with a particular emphasis on technical feasibility and time viability to ensure efficient decommissioning processes [1,19,21,33,45,46,47,49,51]. Predictive risk detection technologies were also highlighted to mitigate the risks of major project failures and enhance monitoring systems [1,21,44]. Financial considerations and the economic implications of decommissioning were discussed in detail, with particular attention to the costs of implementation, impacts on commercial fisheries, and broader economic stimuli, such as employment and taxation [1,13,20,21,26,28,30,33,43,44,45,46,50,52,56]. Societal impacts were also significantly addressed, particularly focusing on enhancing recreational opportunities such as fishing and diving, alongside maintaining clear seabed scenery and unobstructed ocean views, which reflects the growing societal expectations tied to decommissioning activities [1,21,26,30,33,43,52]. As for health and safety, significant emphasis was placed on minimizing risks to personnel, addressing both offshore and onshore safety concerns, such as wellbore integrity and accidental oil spills, to ensure the well-being of all individuals involved [1,13,20,21,28,33,43,50,51,56,57]. Stakeholder involvement became increasingly notable, with studies emphasizing the interest levels of proponents in the decommissioning process [45,46,47]. Perko et al. [58] also investigated societal constraints and the importance of stakeholder engagement in environmental remediation projects.

4.1.4. 2021–2024: Towards Sustainability

From 2021 to 2024, the O&G decommissioning sector increasingly focused on environmental impacts, ensuring the sustainability and responsibility of decommissioning practices. The research predominantly emphasized offshore decommissioning activities together with onshore operations and covered various regions and countries, such as the North Sea [27,29,59,60,61,62], USA-California [23], Brazil [12,34,63,64], Australia [2,65,66], Italy [14], Vietnam [24], and Indonesia [67].

Environmental considerations were particularly prominent, with a major focus on marine ecosystems and the productivity of fish populations. Researchers investigated the broader environmental footprint of decommissioning, including benthic disturbances, habitat changes, and potential contamination that could affect marine life [23,27,65,68]. Technical feasibility remained important, with studies delving into operational equipment, platform integrity, and logistical requirements to ensure the technical viability of decommissioning projects [2,4,5,29,60,62,63]. Innovations in predictive risk detection and the technical training of decommissioning teams were also highlighted to manage complex operations effectively [34,61,66]. Financial considerations continued to be a central theme, with discussions surrounding the economic stimuli from decommissioning, such as effects on local fisheries and broader economic contributions through employment and taxation [2,4,16,27,69]. Societal impacts were explored through public ocean access, public sentiment, and the implications for local communities, emphasizing the need for clear and beneficial engagement with affected populations [4,5,34,63,66]. Health and safety aspects were rigorously addressed, focusing on minimizing risks to decommissioning personnel and public safety, including addressing hazards associated with leftover structures and navigational risks [4,5,27,60,62]. Stakeholder values and engagement were increasingly highlighted, suggesting a more inclusive and transparent practice in decommissioning decision-making [2,29,70,71]. This reflects a mature approach to decommissioning, integrating a wider range of considerations to ensure that projects are technically feasible, environmentally sound, and socially and economically beneficial.

4.2. Regional Disparities and Specialized Focuses

As shown in Figure 6, in the North Sea, Brazil, and Malaysia, there is a continued emphasis on technical aspects. They have addressed operational complexities and logistics, along with exploring alternative barrier materials [26,50,62]. Australia has undergone an environmental shift, particularly evident from 2021 to 2024, with a notable focus on ecological impacts, including connectivity and toxicity assessment [2,65,66]. Italy has centered around societal considerations, particularly ethical dimensions related to decommissioning and the reuse of offshore gas platforms [14]. Furthermore, Thailand, Brazil, Indonesia, and Vietnam have shown increased concerns regarding onshore impacts across various periods, ranging from waste management to the ecological consequences of onshore activities [24,32,50,54,67].

4.2.1. Decommissioning Criteria in the North Sea

In the North Sea, various studies have focused on multiple aspects, from technical to environmental, societal, financial, health and safety, and additional concerns [15,20,27,29,31,35,43,44,59,60,61,62]. The technical aspect has been the most cited consideration, especially in 2023, which focused extensively on the technical elements [62]. This highlights the pivotal role of technological solutions in addressing the complex demands of offshore activities in the region.

Early studies set a precedent by focusing on the logistical and operational complexities of decommissioning [31,35]. The technical aspects, particularly operational equipment and feasibility, have been pivotal, indicating ongoing advancements in decommissioning technologies and methods. Environmental concerns have also been paramount, with an emphasis on the marine ecosystem’s health and productivity highlighted by Vuttipittayamongkol et al. [29], Fortune and Paterson [15], and Nicolette et al. [27]. These studies collectively underscore the critical need for minimizing ecological impacts, focusing on benthic disturbances, fish productivity, and broader marine biodiversity. Financial considerations have been detailed across various studies, with a focus on the economic implications of decommissioning on local fishery industries [20,27,35]. These analyses underscore the need for economic sustainability alongside environmental and technical feasibility. Health and safety concerns have also been addressed, focusing on minimizing risks to personnel and other sea users [31,35,62]. These studies highlight the importance of safety measures and evolving understandings of risks. Additional concerns have focused on stakeholder engagement [29]. They emphasize the need for strong collaborative relationships and high service standards in marine operations to ensure project success.

4.2.2. Decommissioning Criteria in the USA

In California, USA, decommissioning research encompasses a wide range of considerations, including technical, environmental, societal, financial, health, safety, and stakeholder concerns, significantly shaping the region’s approach to offshore operations [17,18,22,23,30,40,41,45,46,47]. These studies illustrate the comprehensive challenges and strategic needs of decommissioning, with financial considerations initially highlighted as a primary focus in 2014 [17].

Technical feasibility and the potential for alternative uses of decommissioned platforms have been key themes, reflecting efforts to enhance efficiency and innovate in the use of offshore structures [41,45]. These studies have addressed risks associated with project failures, underscoring the importance of robust risk management strategies [23]. Environmental impacts have received substantial attention, addressing a broad spectrum of ecological concerns, from benthic disturbances to effects on marine wildlife and habitat [17,18,30]. This research advocates for measures to mitigate adverse effects and promote environmental stewardship. Financial implications remain a significant focus, with analyses detailing the economic impacts on local communities and fishery industries [17,18,22]. This ensures financial strategies are informed and sustainable, addressing both immediate costs and long-term benefits. Societal impacts address public access to ocean resources, recreational opportunities, and the aesthetic value of marine environments [17,22,23,30]. These aspects ensure decommissioning aligns with public interests and community well-being. Health and safety mainly focus on protecting personnel and the public from decommissioning risks [17,23]. Research highlights the need for stringent safety measures and transparent decision-making frameworks aligned with diverse stakeholder values [45,46,47]. This approach ensures that decommissioning efforts are efficient, socially responsible, and widely supported.

4.2.3. Decommissioning Criteria in Brazil

In Brazil, decommissioning research comprehensively covers technical, environmental, societal, financial, and health and safety aspects, reflecting a multi-dimensional approach to offshore and onshore operations [12,34,48,49,50,63,64].

Technical aspects have been a primary focus, particularly in 2023, with studies analyzing operational equipment, logistics, and structural integrity for safe and efficient decommissioning [12]. Environmental concerns have also been prominent, focusing on marine ecosystems, including the effects on marine wildlife and the spread of invasive species [12,34,50,63]. These studies highlight the interconnectedness of marine and terrestrial ecosystems and advocate for strategies to mitigate the ecological impacts of industrial activities. Financial considerations in Brazilian research have centered around the economic viability and broader economic impacts of decommissioning, such as effects on local employment and the fishing industry [12,34,48,50,63]. Societal impacts have addressed enhancing public ocean access and ensuring that decommissioning activities do not compromise the recreational and economic benefits that marine spaces provide to local communities [12,34,63,64]. These aspects highlight the balance between industrial activities and public interests. Health and safety concerns have also been addressed, with studies focusing on the risks associated with offshore operations and the necessary precautions to ensure safety for all involved parties [12,34,49,50,63]. This includes detailed assessments of operational risks and the development of safety protocols to protect both personnel and the broader public.

4.2.4. Decommissioning Criteria in Australia

In Australia, decommissioning research spans a spectrum of technical, environmental, societal, financial, health and safety, and other considerations, reflecting a holistic approach to managing maritime operations [2,51,52,65,66]. Environmental considerations have been the most cited in various environmental elements, especially in 2021 [2,65]. This highlights the pivotal role of environmental solutions in addressing the complex demands of offshore activities in the region.

Technical aspects of Australian maritime operations focus on the design and implementation of offshore structures, emphasizing the need for robust structural integrity and innovative engineering solutions to enhance safety and efficiency [2,51,66]. These studies highlight the critical role of advanced technologies in adapting to harsh marine conditions [51,66]. Environmental research addresses the impacts of decommissioning on marine ecosystems, exploring concerns like fish productivity, biodiversity, and invasive species [2,52,65,66]. Melbourne-Thomas et al. [2] offered insights into contamination, habitat changes, and broader ecological dynamics. Financial considerations focus on the economic impacts of maritime operations, particularly on the fishing industry. Studies explored the effects of restricted fishing activities and overfishing, emphasizing sustainable practices for long-term viability [52,65]. Societal impacts highlight the importance of public ocean access and supporting recreational activities like fishing and diving, which are vital for local communities and the economy [2,52,65]. Health and safety concerns address the risks of offshore decommissioning and the need for stringent safety protocols to protect personnel. Chandler et al. [51] and Janjua and Khan [66] discussed the challenges of managing hazardous materials and the structural integrity of decommissioning operations, stressing the importance of comprehensive safety measures. Melbourne-Thomas et al. [2] highlighted the importance of stakeholder involvement in maritime operations management. This focus reflects a broader trend towards participatory governance, recognizing that effective management requires a collaborative approach that considers complex stakeholder landscapes.

4.2.5. Decommissioning Criteria in Malaysia

In Malaysia, research in various domains related to offshore activities has been progressively undertaken, addressing technical aspects, environmental impacts, societal issues, financial implications, and additional concerns [19,26,39]. The focus on technical aspects, particularly highlighted in 2017, underscores the critical importance of technological solutions in ensuring the operational success and safety of offshore platforms [19].

Technical considerations have emphasized the optimization of operational equipment and platform integrity. Zawawi et al. [39] explored essential factors such as platform type selection and resource management. To ensure the durability and stability of offshore structures under operational and environmental stresses, Na et al. [19] further conducted a detailed analysis of platform types, weight management, logistics requirements, and structural integrity. Environmental concerns have focused on maritime operations’ impact on marine ecosystems, particularly fish productivity, and effects on fisheries and biodiversity [26]. This research highlights the need for sustainable practices that safeguard marine life. Financially, Al-Ghuribi et al. [26] examined the economic ramifications of maritime operations on commercial fisheries, addressing restricted fishing activities and overfishing. These insights are pivotal for understanding the economic impact of marine policies on local economies and fish stock sustainability. Societally, the impact of offshore activities extends to recreational fishing and the broader utilization of maritime spaces by local communities. Al-Ghuribi et al. [26] discussed how these activities influence the local quality of life and the attractiveness of marine areas for tourism and recreation, essential components of the local economy. These studies from Malaysia offer a multi-dimensional perspective on maritime operations, ensuring that offshore activities are technically feasible, environmentally responsible, economically beneficial, and socially conclusive [19,26,39].

4.2.6. Decommissioning Criteria in Other Countries

Research on offshore activities in Mexico has focused on the technical aspects, emphasizing the need for sophisticated technological solutions to enhance operational efficiency and safety in offshore projects [33,53]. As for environmental influence, Van Elden et al. [53] introduced the concept of novel ecosystems, highlighting significant human-altered ecosystems. Additionally, societal impacts, particularly on recreational fishing, have been noted for their cultural and economic importance to local communities [33]. Financial analyses have evaluated the economic effects on commercial fisheries, highlighting the broader economic footprint of maritime operations [33]. Health and safety perspectives are thoroughly covered, ensuring the well-being of personnel involved in offshore activities [33].

In Thailand, research has consistently addressed the technical and environmental aspects of offshore activities, reflecting the country’s focus on both onshore and offshore operations [32,54]. Tularak et al. [32] emphasized robust practices for dismantling and disposal processes, while Kankamnerd et al. [54] focused on managing end-of-life infrastructure. Both studies assessed environmental impacts, including marine biodiversity and artificial reefs. Financial considerations addressed taxation and finance security arrangements for managing aging infrastructure [32]. Stakeholder involvement is highlighted as essential for successful maritime operations [32]. It suggests a collaborative approach to decommissioning that considers various community and industry perspectives.

In Italy, the focus has been more on the societal and ethical aspects of offshore activities, particularly in the context of offshore decommissioning platforms [14]. The study provides a critical insight into how ethical considerations can guide the decommissioning or repurposing of offshore platforms [14]. By framing the decision-making process within an ethical context, the study offers a novel perspective on sustainable development challenges in the offshore O&G sector, advocating for decisions that are socially responsible.

In Vietnam, the research addresses technical and environmental aspects, focusing on onshore disposal facilities and waste production [24]. The study offered valuable insights into the technical intricacies of maritime operations in the region, emphasizing the importance of addressing critical elements such as the accessibility of disposal facilities and the handling of hazardous waste to ensure sustainable practices [24]. Additionally, the study underscores effective waste management in preventing pollution and minimizing the ecological footprint of maritime activities, highlighting the need for integrating sustainable practices throughout the life-cycle of operations [24]. These challenges emphasize the continual improvement in technology and processes to enhance environmental protection and operational efficiency in the region.

Meanwhile, in Indonesia, research has focused on technical and environmental aspects related to offshore activities, particularly emphasizing the importance of onshore disposal facilities and waste management [67]. This study provided insightful analysis regarding the technical challenges and requirements for onshore disposal facilities, stressing the need for well-located and adequately equipped facilities to ensure efficient and sustainable waste management practices. The research also highlights the significant environmental challenges posed by waste production and contamination, underscoring the importance of effective strategies to minimize waste generation and prevent the release of harmful substances into the environment.

4.3. Mapping Oil and Gas Decommissioning Criteria to Onshore Procedures

Considering the decommissioning of O&G facilities, the complexities extend beyond offshore to onshore operations, governed by stringent national and international regulations aimed at safeguarding environmental integrity [8,9]. For example, one significant challenge includes determining the extent of decommissioning obligations after the owner’s contract for a particular site has expired. Such complexities are particularly relevant in onshore projects, where legal and operational responsibilities might differ from those in offshore contexts.

Based on this analysis, this study organizes the key steps of onshore decommissioning into a clear framework, detailing procedures for the preparation and execution of O&G onshore decommissioning activities. As shown in Figure 7, the owner’s decommissioning obligations continue until all legal and environmental requirements are fully met, ensuring that the site is returned to a safe and stable condition.

Due to limited study of the onshore decommissioning of O&G, this study reviewed some research that addressed both offshore and onshore decommissioning of O&G [10,11,24,32,38,50,54,56,57,67]. It aims to capture the connection between the onshore decommissioning procedures within the identified six dimensions, as shown in Figure 8. Notable gaps persist in the dimensions of technical, environmental, societal, financial, and additional concerns. For technical aspects, operational equipment, platform integrity, waste handling, and service lifecycle evaluation are well-documented [32,38,50,54,56,67]. However, predictive risk detection remains underexplored. Environmental influence has centered on marine ecosystems [32,50,54,56]. For environmental influence, it is reasonable to consider the aquatic ecosystem during the preparation phase [54,56]. However, the terrestrial influence should also be considered in the preparation phase, in addition to onshore decommissioning execution and post-decommissioning phases [50,54,56]. Societal impact studies have addressed public emotion dynamics [56], yet public resource availability, recreational opportunities, and operating company reputation require further investigation. Financially, while liabilities, operational costs, and economic challenges are covered [32,50,56], impacts on onshore commercial fisheries need attention. Health and safety concerns focus on personnel and public safety risks [38,50,56,57]. While stakeholder concerns are assessed [32], other concerns, such as the interest level of the proponents and the service provided by contractors, remain to be explored.

To understand the duration of the onshore decommissioning process, this study further investigates the timelines of MCDA-based O&G decommissioning. It can vary significantly depending on several factors, including the complexity of the project, the regulatory environment, the specific criteria being evaluated, and the availability of data [4,5,12]. However, based on the decommissioning practices of Brent Field [10,11], the expected process comprises four main phases: Preparation and Planning (2–3 months), Option Evaluation (1–3 months), Decision-Making and Regulatory Approval (3–6 months), and Execution of Decommissioning (12–36 months). Consequently, the entire MCDA-based evaluation and decommissioning process can span from 1.5 to 4 years. It underscores the necessity for thorough planning, effective stakeholder engagement, and strict adherence to regulatory frameworks to ensure safe and efficient decommissioning outcomes.

5. Discussions and Recommendations

5.1. Discussions

This study provides a comprehensive analysis of the MCDA framework used in the decommissioning of O&G infrastructure, highlighting key trends, regional disparities, and evolving criteria. The shift from technical to environmental considerations reflects a growing global awareness of the environmental impacts of decommissioning activities [65]. This trend aligns with the broader sustainability goals and emphasizes the importance of integrating environmental criteria into decision-making processes [3].

The regional disparities observed, such as the technical focus in the North Sea and environmental emphasis in Australia, underscore the need for tailored decommissioning strategies that consider local conditions and stakeholder priorities [2,65]. For instance, the North Sea’s emphasis on technical aspects reflects the region’s mature decommissioning industry and the complex operational challenges it faces [62]. In contrast, Australia’s focus on environmental impacts aligns with its strong regulatory framework and commitment to marine ecosystem protection [2,52,65,66].

The refined framework of criteria developed in this study provides a comprehensive tool for stakeholders to evaluate decommissioning options [17]. It ensures that decisions are scientifically robust and consider long-term environmental safety, economic viability, and societal impacts [18]. The framework’s adaptability to both offshore and onshore decommissioning projects marks a significant advancement in managing the complexities of decommissioning practices [19].

5.2. Recommendations

This study provides a systematic guide for decision-making in the decommissioning of oil and gas facilities. However, industry practitioners need to consider specific potential challenges when applying this framework in practice. For example, local communities may prioritize environmental protection, while industry stakeholders might be more focused on cost-effectiveness, leading to potential stakeholder conflicts. Additionally, varying regional regulations and legal requirements may complicate the application of a standardized framework. Technical aspects of decommissioning can also be challenging, such as the safe dismantling of infrastructure and waste management, especially in onshore decommissioning.

Based on the findings of this study, the following are some recommendations for industry practitioners:

(1) Future decommissioning projects are required to enhance their environmental focus

Decommissioning projects should prioritize environmental criteria, which reflects the global shift towards sustainability. This includes rigorous environmental impact assessments and the integration of ecological considerations into all stages of decommissioning [15,16]. By focusing on minimizing environmental impacts, companies can ensure that decommissioning activities do not harm marine and terrestrial ecosystems. Additionally, implementing best practices in environmental management can enhance the reputation of the industry and gain public support. Companies should invest in technologies that reduce environmental footprints and adopt strategies that promote biodiversity and habitat restoration.

(2) Tailoring the decommissioning strategies is necessary to strengthen regional effectiveness

Strategies should be tailored to regional specifics. For example, regions like the North Sea, which has a mature decommissioning industry, should focus on enhancing technical innovations, while regions like Australia should continue to emphasize environmental protection [2,65,66]. Understanding the unique regulatory, environmental, and operational contexts of different regions is crucial for effective decommissioning. In the North Sea, technological advancements can address complex operational challenges and improve efficiency. In contrast, Australia’s strategies should focus on preserving marine ecosystems and complying with strict environmental regulations. Tailored approaches ensure that decommissioning practices are not only compliant but also optimized for local conditions.

(3) Onshore decommissioning frameworks should be emphasized based on comprehensive studies

Onshore decommissioning presents unique challenges, such as managing land contamination, waste disposal, and community impacts [10,11,24,32,38,50,54,56,57,67]. Detailed studies can provide insights into best practices for mitigating these impacts and ensuring safe and sustainable decommissioning. Developing robust frameworks that address the full lifecycle of onshore decommissioning activities can improve project planning and execution. This focus will also support the creation of policies and regulations that protect terrestrial environments and public health.

6. Limitations and Further Study

This study highlights several points for consideration and improvement. A primary limitation is the delay in incorporating industry changes or emerging technologies into decommissioning practices due to publication timelines. Additionally, research on decommissioning in some regions, such as Gulf countries, Russia, and China, remains limited. To enhance the applicability of the theoretical framework, it is essential to include more case studies and empirical data. Future research should focus on developing a more detailed understanding of the environmental impacts of onshore decommissioning. Another area for further study is the economic assessment of decommissioning projects, examining the cost-effectiveness of various techniques and their financial implications for stakeholders. Furthermore, expanding research to include Gulf countries and other underrepresented regions will help capture the unique challenges and contributions of these areas to the field.

7. Concluding Remarks

Despite extensive research on criteria for O&G decommissioning, significant gaps remain in the post-decommissioning phase, including onshore procedures and corresponding criteria. This oversight can lead to suboptimal outcomes for stakeholders and hinder the implementation of sustainable practices. Therefore, this study undertakes a systematic literature review with a specific focus on MCDA studies on decommissioning practices. It also identifies and analyzes evolving trends and regional disparities in MCDA for decommissioning and maps the consolidated criteria to O&G onshore decommissioning procedures.

The research methodology was adapted from Cooper et al. [25] and structured into five steps. This approach allowed for a thorough aggregation and analysis of existing literature. After a screening process for scientific articles, 63 references were scrutinized, resulting in the identification of 158 criteria within 22 factors across 6 dimensions. The statistical analysis revealed significant trends and distribution patterns in the literature on decommissioning O&G facilities. Interpreting and outcomes synthesis explored how decommissioning criteria have evolved across different periods and examined the specific concerns across various regions. The focus shift from technical to environmental marks a growing global awareness of the environmental impacts of decommissioning activities. The regional variations emphasized technical aspects in the North Sea and environmental considerations in Australia. The study also constructed a systematic onshore decommissioning procedure and identified connections between these processes and consolidated criteria.

It further proposed suggestions for industry practitioners: (1) future decommissioning projects are required to enhance their environmental focus, (2) tailoring the decommissioning strategies is necessary to strengthen regional effectiveness, and (3) onshore decommissioning frameworks should be emphasized based on comprehensive studies. Limitations and possibilities for further study are also identified.