断裂及其裂缝发育带在塔中油气勘探中的意义

Significance of Fault and Fracture Developing Area in Oil and Gas Exploration in Tazhong

针对塔中西部Z15井区储层非均质性强、主要目的层埋藏较深(一般>5 000 m)、地震资料品质差、小断层识别困难且多产状较陡的难题,总结出易于操作的小断裂解释判别原则:即寒武系盐层顶面有断距、灰岩顶部有挠曲、地震剖面上断层轨迹有串珠、碳酸盐岩内幕地震同相轴有相变。相对较准确地刻画了研究区4期断裂的平面和剖面分布特征,其中第二期近东西向中晚加里东期逆冲推覆断裂和第三期近南北向的晚加里东—早海西期扭张性走滑断裂是研究区的主要断裂,控制了研究区奥陶系储层和油气藏的分布。并通过多口井的钻探证实,断裂及其控制的裂缝发育带是高产稳产井的分布区域,其富含油气主要得益于:优质的储层发育;断裂期次早于油气成藏且封盖条件好,油气保存完整;良里塔格组水体能量弱。围绕断裂及其裂缝发育带的优质储层发育区的钻探为断裂控储控藏研究和寻找新的油气富集区域开拓了新的思路。

In view of the problems of the strong heterogeneity in the formation of Z15 well field in western Tazhong,the buried depth of the main formation of interest over 5 000 meters,the bad quality of seismic data,and minor faults to be difficult to identify,and so on,we present the diicrimination method for the minor fault interpretation to be easy to implement.Namely,amplitude on top of theicambrian salt bed,twist on top of limestone bed,paternoster in the seismic siction,and ficiesichange of seismic lineup inicarbonate inside. By these methods,the faults are deicribed iccurately in plane and siction. The west-east diriction overriding fault developed in middle and lateicaledonian and transtension strike-slip fault developed in lateicaledonian and early Heicynian is the main faults system in Z15 well field andicontrolling the distribution of formation and reservoir. Several wells drilled through fault in this well field prove that the fault and fricture developing area are favorable for high prodiction well. Fault and fricture developing area are good to be drilled bicause of its well-developed formation,welliconserved hydricarbon and weak aquifer energy in Lianglitage group. This will break new ground for reseaiches formation and reservoir related to fault. And it will also help to diicover new oil and gasicoicentration area.