An Analysis on Wellbore Collapse of Open Hole Completion in Carbonate Formation

Abstract

In TK oilfield, there is a large content of carbonatite in cambrian-ordovician, with great depth 4500m-6300m, high temperature 120oC -140oC, anisotropy, developed fracture system and complexity in geological structure. This paper is concerned about wellbore collapse in open hole completion of well R1 and other wells in the collepse well area, and trying to solve this problem through statistics of collapsed wells, and calculate with the mechanics model coupled with temperature field, fluid flow field and rock-mud physicochemical reactions. The result show that the development of hydration stress in planes of weakness, occurrence of nature fractures and technic stress are the most influential factors on wellbore stability. A wellbore in a formation with nature fractures around the wellbore has a testing pressure difference window of 21-28MPa.