威荣深层页岩储层水力压裂多井压窜现象及机理  

Phenomenon and mechanism of multi-well frac hits hydraulic fracturing in Weirong deep shale reservoir

作　　者：胡永章[1] 唐煊赫 朱海燕 钟敬敏[1] 慈建发[1] 林世立 何永生 杨海心 HU Yongzhang;TANG Xuanhe;ZHU Haiyan;ZHONG Jingmin;CI Jianfa;LIN Shili;HE Yongsheng;YANG Haixin(Petroleum Engineering Technology Institute,Southwest Oil and Gas Company,SINOPEC,Deyang 618000,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;College of Energy,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]中国石化西南油气分公司石油工程技术研究院,四川德阳618000 [2]成都理工大学油气藏地质及开发工程国家重点实验室,四川成都610059 [3]成都理工大学能源学院,四川成都610059

出　　处：《断块油气田》2024年第5期851-857,863,共8页Fault-Block Oil & Gas Field

基　　金：国家自然科学基金青年基金项目“深层页岩缝口暂堵压裂多簇复杂裂缝交错扩展机理研究”(52204005);四川省自然科学基金青年基金项目“四川盆地深层页岩气藏暂堵压裂缝网形成机理研究”(2023NSFSC0944)。

摘　　要：威荣深层页岩气田五峰组—龙马溪组储层埋藏深,地质构造复杂,强非均质性天然裂缝发育,地应力高且水平地应力差大,非连续性构造在高临界应力环境下易出现扰动失稳。在储层局部连续裂缝带发育和高应力环境的共同作用下,前期400 m井距条件下出现邻井压窜和多井巷道压窜现象,导致大量生产井产能下降、续建井井壁失稳及套变问题。针对以上问题,文中基于地质-工程一体化思路,考虑了多种复杂天然裂缝分布特征和复杂裂缝扩展应力干扰效应,建立了基于DFN-FEM的井组压裂复杂裂缝扩展模型。研究发现:1)天然裂缝带和大型断裂是多井巷道压窜的主要地质因素;2)天然裂缝面法向刚度越小,压裂应力扰动范围越大,压窜越严重;3)内摩擦角和内聚力越小,岩石越容易破裂并诱发压窜;4)井组压裂顺序对压窜类型和程度均有显著影响,交错压裂最优。该研究结果可为威荣页岩储层水平井井间干扰防治与产能恢复提供依据,进而有效支撑以威荣为代表的深层页岩气田的安全高效开发。The reservoirs of Wufeng Formation and Longmaxi Formation in Weirong deep shale gas field have deep burial depth,complex geological structure,strong heterogeneous natural fractures,high ground stress and large horizontal ground stress difference,and discontinuous structures are prone to disturbance and instability under high critical stress environment.Under the joint action of local continuous fracture zone development and high stress environment,frac hits in adjacent wells and multi-well roadway occurred under the condition of 400 m well spacing in the early stage,which led to the decrease of productivity of a large number of production wells,borehole instability and casing change of continuous wells.In view of the above problems,based on the idea of geological-engineering integration,the distribution characteristics of multiple complex natural fractures and the disturbance effect of complex fracture propagation stress are taken into account,and a well group fracturing complex fracture propagation model based on DFN-FEM is established in this paper.The results show that:(1)Natural fracture zone and large fracture are the main geological factors of multi-well roadway pressure channeling.(2)The smaller the normal stiffness of natural fracture surface,the larger the fracturing stress disturbance range and the more serious the frac hits.(3)The smaller the internal friction angle and cohesive force,the easier the rock is to break and induce frac hits.(4)The fracturing sequence of well group has a significant influence on the type and degree of frac hits,and the staggered fracturing is the best.The research results can provide a basis for the prevention and control of inter-well interference and productivity recovery of Weirong shale gas horizontal wells,and then effectively support the safe and efficient development of deep shale gas fields represented by Weirong.

关 键 词：井间干扰 多井压裂 复杂构造 深层页岩气 威荣气田 

分 类 号：TE37[石油与天然气工程—油气田开发工程]