四川盆地灯影组酸压裂缝导流能力实验和模拟研究  

Experimental and simulation study on fracture conductivity of acid-fracturing in Dengying Formation of Sichuan Basin

作　　者：陈祥[1,2] 王冠 刘平礼[1,2] 杜娟 王铭[1,2] 陈伟华[3] 李金龙 刘金明[1,2] 刘飞[3] CHEN Xiang;WANG Guan;LIU Pingli;DU Juan;WANG Ming;CHEN Weihua;LI Jinlong;LIU Jinming;LIU Fei(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Petroleum Engineering School,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Engineering Technology Research Institute of PetroChina Southwest Oil and Gas Field Company,Chengdu,Sichuan 610017,China)

机构地区：[1]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 [2]西南石油大学石油与天然气工程学院,四川成都610500 [3]中国石油西南油气田分公司工程技术研究院,四川成都610017

出　　处：《油气藏评价与开发》2024年第4期569-576,共8页Petroleum Reservoir Evaluation and Development

基　　金：中国石油—西南石油大学创新联合体科技合作项目“深层超高温(200℃)碳酸盐岩气藏酸处理增产改造关键技术研究”(2020CX0105)。

摘　　要：酸压是深层、超深层海相碳酸盐岩油气藏增产的核心技术,而如何在超高温和高闭合应力下保持住酸蚀裂缝导流能力是酸压改造能否成功的关键。利用自研的高温高压酸蚀裂缝导流能力测试装置开展不同酸液及组合下灯影组岩样裂缝导流能力实验,使用三维激光扫描仪获取酸刻蚀裂缝形貌,基于此,采用Airy(艾里)应力函数和复变量法,描述酸蚀裂缝闭合程度,结合局部立方定律,耦合酸压模型,形成了酸蚀裂缝导流能力数值计算方法。结果表明:与低闭合应力(5MPa)相比,高闭合应力(90MPa)下多数酸液及其组合的导流能力降低了一个数量级;闭合应力增加,不同酸液及组合的导流能力降低模式有较大区别,可能会出现2次快速下降阶段;不同酸液组合注入可在一定程度上改善超高温和高闭合应力下酸蚀裂缝导流能力;酸蚀裂缝导流能力计算模型与实验结果平均误差较小,约10.6%,且能表征缝内各处导流能力分布及大小;相同工程参数条件下,四川盆地灯影组四段酸压裂缝导流能力较灯影组二段更高,可为四川盆地深层、超深层海相碳酸盐岩酸压改造方案优化设计提供理论指导。Acid fracturing is a critical stimulation technology for enhancing production in ultra-deep marine carbonate reservoirs.A significant challenge in this process is maintaining the conductivity of acid-etched fractures under ultra-high temperature and high closure stress conditions.To address this,conductivity experiments were conducted using various acid solutions and their combinations.The morphology of the acid-etched fractures was captured using a three-dimensional laser scanner.The degree of fracture closure was analyzed using the Airy stress function and the complex variable method,integrated with the local cubic law and an acid fracturing model to create a numerical calculation method for evaluating the conductivity of acid-etched fractures.The results show that under high closure stress(90 MPa),the conductivity of acids and their combinations decreases by an order of magnitude compared to low closure stress(5 MPa).As closure stress increases,different acids and combinations exhibit distinct patterns of conductivity reduction,with potential for two rapid decline phases.Furthermore,specific acid combinations have been identified that enhance the conductivity of fractures under extreme conditions of temperature and pressure.The average error between the conductivity values calculated by the model and those obtained from experimental results is relatively low,about 10.6%,indicating that the model can effectively characterize the distribution and magnitude of conductivity across different points within the fracture.In Sichuan Basin,under identical engineering parameters,the conductivity of acidetched fractures in the 4th member of Dengying Formation is higher than that in the 2nd member.This research provides valuable theoretical guidance for optimizing the design of acid fracturing stimulation schemes in ultra-deep marine carbonate rocks in Sichuan Basin.

关 键 词：碳酸盐岩 酸压 导流能力 酸液组合 数值模拟 

分 类 号：TE357[石油与天然气工程—油气田开发工程]