川南深层页岩气藏压裂裂缝导流能力影响因素分析  

Analysis of Factors Affecting the Fracture Conductivity in Deep Shale Gas Reservoirs of Southern Sichuan

作　　者：杨亚东 邹龙庆 王一萱 朱静怡[2] 李小刚[2] 熊俊雅 Yang Yadong;Zou Longqing;Wang Yixuan;Zhu Jingyi;Li Xiaogang;Xiong Junya(CNPC Chuanqing Drilling Engineering Company Limited,Chengdu,Sichuan 610500,China;State Key Laboratory of Oil&Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China)

机构地区：[1]中国石油川庆钻探工程有限公司,四川成都610500 [2]西南石油大学油气藏地质及开发工程全国重点实验室,四川成都610500

出　　处：《特种油气藏》2024年第5期162-167,共6页Special Oil & Gas Reservoirs

基　　金：四川省青年基金“耐高温自生泡沫压裂液生成规律及其携砂机理研究”(2022NSFSC1036)。

摘　　要：深层页岩油藏具有高闭合压力、高地层温度、高弹性模量的特点,通过压裂获得高导流能力裂缝的难度较大。为实现对深层页岩气藏压裂缝的有效支撑与维持,以四川威远区块深层页岩为例,基于自主改进的API裂缝导流能力测试平台,研究了高闭合压力(82.8 MPa)和高地层温度(160℃)对支撑裂缝导流能力的影响规律,对比了不同支撑剂类型和组合方式下导流能力的差异,分析了自支撑裂缝在深层页岩条件下的适应性。研究表明:高闭合压力是支撑裂缝导流能力降低的主控因素,在82.8 MPa的高闭合压力下,增加铺砂浓度对导流能力的正向效果已不再明显;高温环境会增大支撑剂的破碎与嵌入程度,温度越高,导流能力越低;40/70目陶粒支撑剂的裂缝导流能力明显大于70/140目石英砂和微纳米支撑剂的导流能力;石英砂与陶粒(质量比为1∶1)分段铺置比全域混合铺置的导流能力高,更具有经济性;自支撑裂缝壁面的凸起点在高闭合压力下易被压碎,导流能力呈现较强的应力敏感,不利于生产后期导流能力的维持。该研究结果可为深层页岩气藏压裂参数的设计和导流能力的优化提供理论支撑。Deep shale reservoirs are characterized by high closure pressure,high formation temperature,and high elastic modulus,making it challenging to achieve high conductivity fractures through fracturing.To effectively support and maintain pressure fractures in deep shale gas reservoirs,taking the deep shale of the Weiyuan Block in Sichuan as an example,based on an self-developed testing platform of API fracture conductivity,this study investigated the impact of high closure pressure(82.8 MPa)and high formation temperature(160℃)on the conductivity of supported fractures.The differences in conductivity under different types and combinations of proppants are compared,and the adaptability of self-supported fractures under deep shale conditions is analyzed.The results indicates that the high closure pressure is the main controlling factor for the decrease of fracture conductivity.Under the high closure pressure of 82.8 MPa,the positive effect of increasing sand concentration on conductivity is no longer evident;the high-temperature environment increases the degree of proppant breakage and embedment,with higher temperatures resulting in lower conductivity;the fracture conductivity of 40/70 mesh ceramsite proppant is significantly greater than that of 70/140 mesh quartz sand and micro-nano proppants;the conductivity of quartz sand and ceramsite(mass ratio of 1∶1)placed in sections is more economical and has higher conductivity than the whole mixed placement;the convex points on the wall of self-supported fractures are easily crushed under high closure pressure,showing strong stress sensitivity in conductivity,which is not conducive to maintaining conductivity in the later stages of production.The results of this study provide theoretical support for the design of fracturing parameters and optimization of conductivity in deep shale gas reservoirs.

关 键 词：深层页岩 导流能力 高闭合压力 高储层温度 自支撑裂缝 

分 类 号：TE37[石油与天然气工程—油气田开发工程]