川西南井研地区灯影组断裂对储集条件的影响

Influence of faults on reservoir conditions of Dengying formation in Jingyan area,southwest Sichuan

井研地区灯影组整体为局限台地沉积,有利储层为藻丘相的富藻白云岩及粒屑白云岩。近期钻井揭示灯影组含气性横向差异明显,气藏影响因素不明确。灯影组主要发育两类断裂体系,一类为桐湾运动形成的桐湾期断裂体系,多为小型断裂,由于该类断裂多为层间断裂或仅断至寒武系,因此不会成为油气散失通道,使沿断裂形成的储集体可能形成岩性圈闭;第二类为多期次继承性大断裂,大部分向上断至二叠系以浅,这类断裂易成为油气散失通道,不利于油气的聚集。通过研究认为,井区断裂发育情况对各井储层条件具有重要影响,并对井区气藏起重要控制作用。

Dengying formation in Jingyan area is a restricted platform deposit,and the favorable reservoirs are algae-rich dolomite and granular dolomite of algal mound facies.The recent drilling results show that the gas bearing property of Dengying formation has obvious lateral difference,and the influencing factors of gas reservoir are not clear.Two kinds of fault systems are mainly developed in Dengying formation,one is Tongwan stage fault system formed by Tongwan movement,and most of them are small faults.Because most of these faults are interbedded or only break to Cambrian,they will not become oil and gas loss channels,so that the reservoirs formed along the faults may form diagenetic traps.The second type is multi-stage inherited large faults,most of which break upward to the shallow of Permian system.This kind of faults are easy to become oil and gas loss channels,which is not conducive to oil and gas accumulation.The study shows that the development of faults in the well area has an important impact on the reservoir conditions of each well and plays an important role in controlling the gas reservoir in the well area.