Next Article in Journal
Sliding Mode-Based Robust Control for Piezoelectric Actuators with Inverse Dynamics Estimation
Previous Article in Journal
Is It Possible to Supply Norwegian Apartment Blocks with 4th Generation District Heating?
Previous Article in Special Issue
A Thermo-Hydro-Mechanical-Chemical Coupling Model and Its Application in Acid Fracturing Enhanced Coalbed Methane Recovery Simulation
Article Menu
Issue 5 (March-1) cover image

Export Article

Open AccessArticle
Energies 2019, 12(5), 942; https://doi.org/10.3390/en12050942

Uncertainty Evaluation of Safe Mud Weight Window Utilizing the Reliability Assessment Method

1
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China
2
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
*
Authors to whom correspondence should be addressed.
Received: 8 January 2019 / Revised: 26 February 2019 / Accepted: 8 March 2019 / Published: 12 March 2019
Full-Text   |   PDF [6858 KB, uploaded 12 March 2019]   |  

Abstract

Due to the uncertainty of formation properties and improper wellbore stability analysis methods, the input parameters are often uncertain and the required mud weight to prevent wellbore collapse is too large, which might cause an incorrect result. However, the uncertainty evaluation of input parameters and their influence on safe mud weight window (SMWW) is seldom investigated. Therefore, the present paper aims to propose an uncertain evaluation method to evaluate the uncertainty of SMWW. The reliability assessment theory was introduced, and the uncertain SMWW model was proposed by involving the tolerable breakout, the Mogi-Coulomb (MG-C) criterion and the reliability assessment theory. The influence of uncertain parameters on wellbore collapse, wellbore fracture and SMWW were systematically simulated and investigated by utilizing Monte Carlo simulation. Finally, the field observation of well SC-101X was reported and discussed. The results indicated that the MG-C criterion and tolerable breakout is recommended for wellbore stability analysis. The higher the coefficient of variance is, the higher the level of uncertainty is, the larger the impact on SMWW will be, and the higher the risk of well kick, wellbore collapse and fracture will be. The uncertainty of basic parameters has a very significant impact on SMWW, and it cannot be ignored. For well SC-101X, the SMWW predicted by analytical solution is 0.9921–1.6020 g/cm3, compared to the SMWW estimated by the reliability assessment method, the reliability assessment method tends to give a very narrow SMWW of 1.0756–1.0935 g/cm3 and its probability is only 80%, and the field observation for well kick and wellbore fracture verified the analysis results. For narrow SMWW formation drilling, some kinds of advanced technology, such as the underbalanced drilling (UBD), managed pressure drilling (MPD), micro-flow drilling (MFD) and wider the SMWW, can be utilized to maintain drilling safety. View Full-Text
Keywords: safe mud weight window; wellbore stability; reliability assessment method; uncertainty evaluation; collapse pressure; fracture pressure; pore pressure safe mud weight window; wellbore stability; reliability assessment method; uncertainty evaluation; collapse pressure; fracture pressure; pore pressure
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Ma, T.; Tang, T.; Chen, P.; Yang, C. Uncertainty Evaluation of Safe Mud Weight Window Utilizing the Reliability Assessment Method. Energies 2019, 12, 942.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Energies EISSN 1996-1073 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top