长宁页岩地层井下复杂及裂缝三维展布规律研究

A Study on Downhole Complex and Three Dimensional Distribution of Fractures in Changning Shale Formation

刘厚彬 于兴川 张震 万秀梅 孙航瑞

LIUHoubin YUXingchuan ZHANGZhen WANXiumei SUNHangrui

油气藏地质及开发工程国家重点实验室·西南石油大学, 四川 成都 610500 中国石油西南油气田公司页岩气研究院, 四川 成都 610051

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China Shale Gas Research Institute, PetroChina Southwest Oil and Gas Field Company, Chengdu, Sichuan 610051, China

长宁区块龙马溪组页岩气储量丰富，是中国石油天然气资源增产上产的重要支撑点。但长宁区块页岩储层钻井中井漏、阻卡事故频发，阻碍了该地区页岩气资源效益化开发进程。通过梳理长宁区块重点井区已钻井工程复杂信息数据，基于区块三维地震数据体利用蚂蚁追踪方法预测了页岩地层裂缝发育及三维空间展布规律，对比研究了井漏与裂缝发育之间响应关系，为长宁区块龙马溪组页岩水平钻井井下复杂预警及安全钻井奠定基础。研究结果表明，基于蚂蚁体的裂缝预测方法在长宁区块应用效果较好，井漏复杂与裂缝预测结果响应度高，裂缝发育、斜交缝与层理缝交叉贯通是诱发井漏事故的主要原因。茅口组-五峰组页岩裂缝发育具有三维空间差异性，构造高部位、大断层附近裂缝发育，岩体较为破碎，井漏复杂更为突出。研究成果解释了长宁区块井下复杂的主要原因，预测了长宁区块裂缝三维展布规律，可为长宁区块后期井下复杂预测及防治措施的制定提供科学依据。

The Changning Block is rich in shale gas reserves in the Longmaxi Formation and is an important support point for China's oil and gas resources to increase production. However, the frequent occurrence of well leaks and blocking accidents in the drilling of shale reservoirs in the Changning Block has hindered the process of beneficial development of shale gas resources in the area. By combing the complex information data of drilled wells in the key well areas of the Changning Block, the ant-tracking method was used to predict the fracture development and 3D spatial spreading pattern of the shale formation based on the 3D seismic data body of the block, and the response relationship between well leakage, jamming complexity and fracture development was comparatively studied to lay the foundation for early warning and safe drilling of horizontal shale drilling wells in the Longmaxi Formation of the Changning Block. The results show that the fracture prediction method based on ant body is better applied in the Changning Block, the response between well leakage complexity and fracture prediction results is high, and fracture development, cross penetration of oblique intersection and laminated joints are the main causes of well leakage and jamming accidents. The fracture development in the shale of the Maokou and Wufeng Formations has threedimensional spatial variability, and the well leakage and jamming complexity is more prominent in the high tectonic areas and near large faults where fractures are developed and the rock is more fragmented. The results of the study explain the causes of well leakage and blocking complexities in the Changning Block and predict the three-dimensional fracture spreading pattern in the Changning Block, which can provide a scientific basis for the prediction of downhole complexities and the formulation of prevention and control measures in the Changning Block at a later stage.

10.11885/j.issn.16745086.2021.04.29.05