Wellbore instability mechanism of shale oil reservoir in Jinghe Oilfield
Aiming at the technical difficulties of wellbore instability in the Yanchang Formation of the Jinghe Oilfield in the southern part of the Ordos Basin,the mineral composition and micro-structure of shale were analyzed,the physical and chemical properties were tested,and the wellbore instability mechanism was re-vealed.The results indicate that the shale of Chang 7 member is characterized by well-developed stratigra-phy and fractures,which belongs to weak water sensitive hard brittle shale.Due to the damage of rock weak structural plane caused by stratigraphy and the reduction of rock structural strength caused by clay hydra-tion,the wellbore instability is caused.Meanwhile,a three pressure profile of shale formation was estab-lished,with an ideal drilling fluid density of 1.13 g/cm3,which has a good reference for＂safe,efficient,and economical＂drilling of shale oil in Jinghe Oilfield.
万方数据
维普
