考虑天然裂缝的页岩储集层多裂缝竞争扩展三维模拟  

Three-Dimensional Simulation of Competitive Multi-FracturePropagation in Shale Reservoirs with Consideration of Natural Fractures

作　　者：凌兴杰 陈琦 黄志强[3] Ling Xingjie;Chen Qi;Huang Zhiqiang(School of Materials and Chemistry,Southwest University of Science and Technology,Mianyang,Sichuan 621010,China;College of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249,China;School of Petroleum Engineering,Yangtze University,Wuhan,Hubei 430000,China)

机构地区：[1]西南科技大学材料与化学学院,四川绵阳621010 [2]中国石油大学(北京)石油工程学院,北京102249 [3]长江大学石油工程学院,湖北武汉430000

出　　处：《特种油气藏》2024年第5期136-145,共10页Special Oil & Gas Reservoirs

基　　金：中国石化科技部项目“川西中浅层致密砂岩气藏体积压裂关键技术”(P22047);中国石油川庆钻探工程有限公司项目“压裂靶向暂堵关键施工参数优化设计技术及现场试验”(CQCJ-2001-06)。

摘　　要：传统页岩裂缝扩展模拟大多局限于二维模型,且未考虑多裂缝同步竞争扩展机理,压裂施工方案大多基于统计分析和现场经验实施,无法有效筛选出强敏感性复杂缝网压裂效果影响参数。针对该问题,以威远区块W204H井区实际储层为例,构建了三维空间下裂缝性地质力学数值模型,考虑多簇压裂中裂缝同步竞争扩展,分析地应力对施工参数的影响,并定量研究地应力差、天然裂缝胶结强度、射孔参数及压裂液排量对复杂缝网体积的影响。结果表明:地应力差越大,天然裂缝激活概率和缝网复杂性越低;天然裂缝胶结强度越小,越容易激活并捕获水力裂缝,当其大于岩石基质强度时,水力裂缝将穿透天然裂缝沿缝高方向扩展;射孔组合密度越大,射孔压降越小,缓解簇间应力干扰能力越弱;压裂液注入速率越高,水力裂缝更倾向于沿天然裂缝扩展,布控密集射孔簇时,应采用大排量和高黏度压裂液以平衡多簇的均匀扩展。该研究可为裂缝性页岩储层的体积压裂优化设计提供理论依据。Traditional simulations of shale fracture propagation are mostly limited to two-dimensional models,and do not consider the mechanism of multi-fracture synchronous competitive propagation.Construction schemes for fracturing are mostly based on statistical analysis and field experience,which cannot effectively screen out the influence parameters of strong sensitivity in complex fracture network fracturing effects.To address this issue,a numerical model of fractured geomechanics in three-dimensional space is developed using the actual reservoir of W204H well area in the Weiyuan Block as a case study.The model takes into account the synchronous competitive propagation of fractures in multi-cluster fracturing and analyzes the impact of in-situ stress on construction parameters.Furthermore,the model quantitatively studies the influence of in-situ stress difference,cementing strength of natural fractures,perforation parameters,and fracturing fluid discharge on the volume of complex fracture networks.The results indicate that a higher in-situ stress difference leads to a lower activation probability of natural fractures and a less complex fracture network.Additionally,a lower cementation strength of natural fractures results in easier activation and capture of hydraulic fractures.When the cementation strength is less than that of the rock matrix,hydraulic fractures will penetrate natural fractures and propagate along the fracture height.Furthermore,a higher perforation combination density results in a smaller perforation pressure drop and a weaker ability to alleviate inter-cluster stress interference.The hydraulic fracture is more likely to propagate along natural fractures with an increase in the injection rate of fracturing fluid.To ensure the uniform propagation of multiple clusters when controlling dense perforation clusters,it is recommended to use large discharge and high viscosity fracturing fluid.This study provides a theoretical basis for the optimal design of volume fracturing in fractured shale reservoirs.

关 键 词：页岩 天然裂缝 多簇压裂 三维地质模型 缝网压裂体积 

分 类 号：TE357[石油与天然气工程—油气田开发工程]