scholarly journals Wellbore stability analysis to determine the safe mud weight window for sandstone layers

2019 ◽  
Vol 46 (5) ◽  
pp. 1031-1038 ◽  
Author(s):  
Ayoub DARVISHPOUR ◽  
Masoud CHERAGHI SEIFABAD ◽  
David Anthony WOOD ◽  
Hamzeh GHORBANI
Keyword(s):  
Stability Analysis ◽  
Wellbore Stability ◽  
Weight Window

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

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 942 ◽  
Author(s):  
Tianshou Ma ◽  
Tao Tang ◽  
Ping Chen ◽  
Chunhe Yang
Keyword(s):  
Stability Analysis ◽  
Field Observation ◽  
Reliability Assessment ◽  
Assessment Method ◽  
Wellbore Stability ◽  
Advanced Technology ◽  
Uncertainty Evaluation ◽  
Weight Window ◽  
Input Parameters ◽  
The Impact

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.

Wellbore Geomechanics of Extended Drilling Margin and Engineered Lost-Circulation Solutions

SPE Journal ◽  
2017 ◽  
Vol 22 (04) ◽  
pp. 1178-1188 ◽  
Author(s):  
Amin Mehrabian ◽  
Younane Abousleiman
Keyword(s):  
Mechanical Properties ◽  
Stability Analysis ◽  
Analytical Approach ◽  
Wellbore Stability ◽  
Tensile Failure ◽  
Mechanical Interaction ◽  
Lost Circulation ◽  
Drilling Operations ◽  
Secondary Fractures ◽  
Lost Circulation Materials

Summary Wellbore tensile failure is a known consequence of drilling with excessive mud weight, which can cause costly events of lost circulation. Despite the successful use of lost-circulation materials (LCMs) in treating lost-circulation events of the drilling operations, extensions of wellbore-stability models to the case of a fractured and LCM-treated wellbore have not been published. This paper presents an extension of the conventional wellbore-stability analysis to such circumstances. The proposed wellbore geomechanics solution revisits the criteria for breakdown of a fractured wellbore to identify an extended margin for the equivalent circulation density (ECD) of drilling. An analytical approach is taken to solve for the related multiscale and nonlinear problem of the three-way mechanical interaction between the wellbore, fracture wings, and LCM aggregate. The criteria for unstable propagation of existing near-wellbore fractures, together with those for initiating secondary fractures from the wellbore, are obtained. Results suggest that, in many circumstances, the occurrence of both incidents can be prevented, if the LCM blend is properly engineered to recover certain depositional and mechanical properties at downhole conditions. Under such optimal design conditions, the maximum ECD to which the breakdown limit of a permeable formation could be enhanced is predicted.

3-D Geomechanical Modeling and Wellbore Stability Analysis in Abu Butabul Field

2012 ◽  
Author(s):  
Qiuguo Li ◽  
Xing Zhang ◽  
Khalid Salim Al-Ghammari ◽  
Labib Mohsin
Keyword(s):  
Stability Analysis ◽  
Wellbore Stability

APPLICATION OF GUIDELINE CHARTS IN DECISIONMAKING ON WELL TRAJECTORY AND MUD WEIGHT PROGRAM

2001 ◽  
Vol 41 (1) ◽  
pp. 609
Author(s):  
X. Chen ◽  
C.P. Tan ◽  
C.M. Haberfield
Keyword(s):  
Stability Analysis ◽  
Case Studies ◽  
In Situ Stress ◽  
Wellbore Stability ◽  
Material Strength ◽  
Stress Regime ◽  
Wellbore Instability ◽  
Well Trajectory

To prevent or minimise wellbore instability problems, it is critical to determine the optimum wellbore profile and to design an appropriate mud weight program based on wellbore stability analysis. It is a complex and iterative decisionmaking procedure since various factors, such as in-situ stress regime, material strength and poroelastic properties, strength and poroelastic anisotropies, initial and induced pore pressures, must be considered in the assessment and determination.This paper describes the methodology and procedure for determination of optimum wellbore profile and mud weight program based on rock mechanics consideration. The methodology is presented in the form of guideline charts and the procedure of applying the methodology is described. The application of the methodology and procedure is demonstrated through two field case studies with different in-situ stress regimes in Australia and Indonesia.

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