深层页岩气井拉链式压裂裂缝扩展及窜通规律  

The law of fracture propagation and connection interference in zipper fracturing of deep shale gas wells

作　　者：王强[1] 王玉丰 胡永全[1] 赵金洲[1] 宋毅 沈骋 WANG Qiang;WANG Yufeng;HU Yongquan;ZHAO Jinzhou;SONG Yi;SHEN Cheng(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Shale Gas Research Institute,PetroChina Southwest Oil&Gas Field Company,Chengdu 610051,China)

机构地区：[1]西南石油大学油气藏地质与开发工程全国重点实验室,成都610500 [2]中国石油西南油气田页岩气研究院,成都610051

出　　处：《石油勘探与开发》2024年第5期1141-1149,共9页Petroleum Exploration and Development

基　　金：国家自然科学基金联合基金项目“深层超深层页岩气水平井压裂缝网高效建造理论与方法研究”(U21B2071);国家自然科学基金“天然气水合物储层蠕变和出砂作用下支撑裂缝导流模型与衰减机理研究”(52304041)。

摘　　要：针对深层页岩气井工厂开发模式下拉链式压裂裂缝扩展及窜扰规律认识不清的问题,基于有限元-离散元方法,建立了考虑天然裂缝带影响的拉链式压裂裂缝扩展流-固耦合模型,采用实验数据与现场监测压力涨幅数据验证了模型的可靠性,并以川南深层页岩气储层为例,研究了不同特征天然裂缝带影响下压裂裂缝的扩展及窜扰规律。结果表明:大逼近角裂缝带对压裂裂缝正向扩展及井间窜通具有阻挡作用,停泵期间水力裂缝在净压力驱动下存在继续扩展行为;高应力差下,随裂缝带逼近角增加,响应井压力涨幅、压裂裂缝总长度分别呈先减小再增加及先增加再减小的趋势;与小逼近角裂缝带相比,大逼近角天然裂缝带发生窜通所需时间更长,窜通难度更大;响应井压力涨幅与裂缝带带宽负相关,与天然裂缝长度正相关;窜通时间、压裂裂缝总长及压裂效率则与裂缝带带宽正相关,与天然裂缝长度负相关;随布孔错位距离增加,裂缝窜通概率减小,但错位距离与响应井压力涨幅、裂缝总长度之间的规律性不明显。In response to the unclear understanding of fracture propagation and intersection interference in zipper fracturing under the factory development model of deep shale gas wells,a coupled hydro-mechanical model for zipper fracturing considering the influence of natural fracture zones was established based on the finite element–discrete element method.The reliability of the model was verified using experimental data and field monitoring pressure increase data.Taking the deep shale gas reservoir in southern Sichuan as an example,the propagation and interference laws of fracturing fractures under the influence of natural fracture zones with different characteristics were studied.The results show that the large approaching angle fracture zone has a blocking effect on the forward propagation of fracturing fractures and the intersection of inter well fractures.During pump shutdown,hydraulic fractures exhibit continued expansion behavior under net pressure driving.Under high stress difference,as the approaching angle of the fracture zone increases,the response well pressure increase and the total length of the fractured fracture show a trend of first decreasing and then increasing,and first increasing and then decreasing,respectively.Compared to small approach angle fracture zones,natural fracture zones with large approach angles require longer time and have greater difficulty to intersect.The width of fractures and the length of natural fractures are negatively and positively correlated with the response well pressure increase,respectively,and positively and negatively correlated with the time required for intersection,the total length of hydraulic fractures,and fracturing efficiency,respectively.As the displacement distance of the well increases,the probability of fracture intersection decreases,but the regularity between displacement distance and the response well pressure increase and the total length of fractures is not obvious.

关 键 词：深层页岩气 拉链式压裂 有限-离散单元 天然裂缝带 裂缝扩展与窜扰规律 

分 类 号：TE345[石油与天然气工程—油气田开发工程]