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wellbore-stability
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A transient fully coupled thermo-poroelastic finite element analysis of wellbore stability
, Article Arabian Journal of Geosciences ; Volume 8, Issue 6 , 2014 , Pages 3855-3865 ; ISSN: 18667511 ; Goodarznia, I ; Shadizadeh, S. R ; Sharif University of Technology
Abstract
Stress variations around wellbores and in the reservoirs are of much interest in subsequent drilling operations, future production, and petroleum reservoir development. Stress variations induced by in situ stresses, pore pressure, and temperature changes during drilling operations may lead to various modes of instabilities in forms of induced fractures and borehole breakouts. Previous studies of thermally induced stresses were primarily based on either assumptions of heat conduction through rock matrix or heat convection, in this case, without considering the effect of solid grain thermal conductivity. To analyze wellbore stability, in the present work, a thermo-poro-mechanical model that is...
Stresses at the Bottom of a Borehole and its Effect on Wellbore Stability
, M.Sc. Thesis Sharif University of Technology ; Goodarznia, Iraj (Supervisor)
Abstract
Instability means that when wellbore is out of circle due to any reasons in which it may be associate with fracture or falling of wellbore wall. Wellbore instability problem in production and exploration wells cause high costs over than 100 million dollars in all over the world in which these costs can be increased to 1 billion dollars so, necessary forecasts for preventing of instability is essential. Up to now, a lot of methods are suggested for investigation of wellbore instability, but in this study, analytical investigation with the help of triaxial tension is considered. Failure criterion and rock behavioral model are two important factors in wellbore stability modeling. In this study,...
Geomechanical Model for Well Path Optimization Based on Inclination, Azimuth and ROP
, M.Sc. Thesis Sharif University of Technology ; Shad, Saeed (Supervisor)
Abstract
The wellbore instability increases the cost of drilling operations due to problems such as pipe sticking and lost circulation, so it is important to find the optimal well path. In this research, building a one-dimensional geomechanical model is investigated, and then the wellbore stability during drilling in different layers is evaluated. The geomechanical model is constructed using available data (well log data, mud logging unit data, and drilling reports) in a study reservoir and the optimal well path is determined by the appropriate inclination and azimuth using the geomechanical properties of the field and the stress regime, taking into account the wellbore stability and shear failure...
Simulation of wellbore stability with thermo-hydro-chemo-mechanical coupling in troublesome formations: an example from Ahwaz oil field, SW Iran
, Article Arabian Journal of Geosciences ; Volume 8, Issue 1 , 2015 , Pages 379-396 ; 18667511 (ISSN) ; Jalayeri, H ; Ghotbi, C ; Pishvaie, M. R ; Sharif University of Technology
Abstract
Wellbore stability is a main concern in drilling operation. Troublesome drilling issues are chemically active formations and/or high-pressure–high-temperature environments. These are mainly responsible for most of wellbore instabilities. Wellbore failure is mostly controlled by the interaction between active shales and drilling fluid in shale formations. The factors influencing this interaction consist of fluid pressure, temperature, composition of drilling fluid, and exposure time. In this paper, a non-linear fully coupled chemo-thermo-poroelasticity model is developed. At first, a fully implicit finite difference model is presented to analyze the problem, and then, it is verified through...
The Effects of Various Parameters on Wellbore Stability During Drilling Through Shale Formations
, Article Petroleum Science and Technology ; Volume 33, Issue 12 , 2015 , Pages 1275-1285 ; 10916466 (ISSN) ; Ghotbi, C ; Pishvaie, M. R ; Sharif University of Technology
Taylor and Francis Inc
2015
Abstract
Field evidence indicates that the thermal and chemical regimes in wellbore considerably affect the wellbore stability. This study presents a general coupled model for transport of solute, solvent and heat including their combined effects on the wellbore stability. Optimization of drilling fluid parameters is crucial for wellbore stability analysis particularly in high pressure-high temperature environments. The coupled effects of chemical potential and temperature gradients on fluid flow significantly change the pore pressure and stress around a borehole. The effects of various parameters such as mud weight, solute concentration gradient, shale properties, and temperature gradient on...
Comparison of wellbore stability of UBD in the case of laser drilling and conventional operation
, Article 76th European Association of Geoscientists and Engineers Conference and Exhibition 2014: Experience the Energy - Incorporating SPE EUROPEC 2014 ; 2014 , Pages 1736-1740 ; ISBN: 9781632666949 ; Nakhaee, A ; Koohian, A ; Irawan, S ; Habibpour, M ; Shahvar, M ; Sharif University of Technology
Abstract
In recent years, growing interest in underbalanced drilling has resulted in the rapid development of its associated equipment technology, practices, and procedures. Underbalanced drilling is used to avoid lost circulation, formation damage, and decreasing weight on bit. However, the risk of wellbore collapse due to lake of hydrostatic mud pressure is high; therefore, using good geo-mechanical model may avoid wellbore instability problems. In order to evaluate the potential for wellbore instability, it is necessary to use an elastoplastic model to compute the stresses and strains around the bore hole. Furthermore, it should be mentioned that the laser drilling process depends extremely on the...