Journal of Petroleum & Environmental Biotechnology

Wellbore stability analysis model including poro-elastic, chemical and thermal effect during underbalanced drilling operation for fractured reservoir

3^rd International Conference and Expo on Oil and Gas

July 13-14, 2017 Berlin, Germany

Reda Rabiee Abdel Azim, Ahmed Elbagir and Saad Balhasan

American University of Ras Al Khaimah, UAE

Posters & Accepted Abstracts: J Pet Environ Biotechnol

Abstract:

Before drilling operation, rock stress is described by the in situ stress, which includes effective overburden stress, effective maximum horizontal stress and effective horizontal stress. As the drilling continues and the hole has been drilled the support provided by the rock will be removed as a result of the drilling operation and supposed to be replaced by the hydrostatic pressure. The statues of the rock surrounding the wellbore will be alter which will redistribute the in situ stress around the wellbore due to the excavation, causing mechanical wellbore stability problems such as hole enlargement, hole reduction, lost circulation and may leads to serious well control problems specially in fractured reservoirs. Therefore preventive measurement should be taken in order to planning stable wellbore and identification of stability problems in the field. In addition, to evaluate the potential for wellbore stability a realistic model is recommended to be used to calculate the stresses and strains around the borehole. Therefore, this paper presents an approach to simulate the wellbore stability under chemo-thermo-poro-elastic conditions. This approach incorporates finite element modeling technique and effective permeability tensor for small to medium generated fractures (length <20 m). The simulation of wellbore stability process is running in underbalance drilling (UBD) technique conditions. This is to prevent formation damage, avoid lost circulation and increase rate of penetration. Where, UBD is also dangerous and may lead to wellbore failure due to absence of positive support created by the hydrostatic of the drilling fluid column. Hence, the application of UBD should be assessed throughout the use of in situ stresses and rock mechanical properties to estimate under which hydraulic drilling conditions in the wellbore is stable. Analytical solutions for stress distribution for isotropic and anisotropic rocks are presented. In addition, a solution for the upper limit for the mud window to prevent tensile failure is developed.

Biography :

Email: reda.abdelazim@aurak.ac.ae