石油学报 ›› 2022, Vol. 43 ›› Issue (6): 849-859.DOI: 10.7623/syxb202206009

• 油田开发 • 上一篇    下一篇

基于相场法的酸压裂缝连通孔洞数值模拟

侯冰1,2, 戴一凡1,2, 范濛3, 张鲲鹏1,2   

  1. 1. 中国石油大学(北京)油气资源与探测国家重点实验室 北京 102249;
    2. 中国石油大学(北京)石油工程教育部重点实验室 北京 102249;
    3. 中国石油勘探开发研究院 北京 100083;
    4. 莱布尼茨汉诺威大学应用数学研究室 德国汉诺威 30167;
    5. 佛罗里达州立大学数学系 美国佛罗里达 FL 32306-4510
  • 收稿日期:2021-02-05 修回日期:2022-02-27 出版日期:2022-06-25 发布日期:2022-06-28
  • 通讯作者: 侯冰,男,1979年5月生,2009年获中国石油大学(北京)博士学位,现为中国石油大学(北京)教授、博士生导师,主要从事石油工程岩石力学方向研究。
  • 作者简介:侯冰,男,1979年5月生,2009年获中国石油大学(北京)博士学位,现为中国石油大学(北京)教授、博士生导师,主要从事石油工程岩石力学方向研究。Email:binghou@vip.163.com
  • 基金资助:
    国家自然科学基金项目(No.U19B6003-05,No.52074311和No.51874328)资助。第一作者及

Numerical simulation of pores connection by acid fracturing based on phase field method

Hou Bing1,2, Dai Yifan1,2, Fan Meng3, Zhang Kunpeng1,2   

  1. 1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China;
    2. MOE Key Laboratory of Petroleum Engineering, China University of Petroleum, Beijing 102249, China;
    3. PetroChina Research Institute of Petroleum Exploration and Development, Beijng 100083, China;
    4. Institutfür Angewandte Mathematik, Leibniz Universität Hannover, Hannover 30167, Germany;
    5. Department of Mathematics, Florida State University, 1017 Academic Way, Tallahassee, FL 32306-4510, United States
  • Received:2021-02-05 Revised:2022-02-27 Online:2022-06-25 Published:2022-06-28

摘要: 碳酸盐岩孔洞连通成串、成群可以有效提高改造体积,但受到高应力差、非均质性和孔洞随机分布等影响,孔洞连通性通常较差。针对碳酸盐岩酸压孔洞连通成串的工程问题,考虑酸压过程中酸液对于岩石的动态影响,引入描述酸岩反应的相场参数,提出一种基于相场法的酸压裂缝扩展模拟方法,对碳酸盐岩储层酸压孔洞连通成串现象进行模拟。对比了酸压与滑溜水压裂的裂缝扩展特征,分析了不同孔洞大小与分布情况下孔洞结构对酸压裂缝扩展的影响。根据模拟分析结果可知:1与普通水力裂缝相比,酸压裂缝扩展时缝宽增大,缝长降低,裂缝扩展速度降低;同时裂缝表面岩石被酸液腐蚀,裂缝表面粗糙程度明显上升;2孔洞结构会诱导酸压裂缝扩展,裂缝在酸化区域扩展时,靠近孔洞处的扩展速度更高;3缝洞型储层酸压过程中,孔洞半径越大,距离裂缝原扩展路径越近,裂缝越易发生转向,且越容易沟通多个孔洞,多孔洞连通成串可以有效提高泄流面积。

关键词: 孔洞连通, 酸压, 碳酸盐岩储层, 裂缝扩展, 相场法

Abstract: Although the connection of carbonate rock pores in groups and clusters can effectively increase the transformation volume, the connectivity is poor due to high stress difference, non-homogeneity and random distribution of pores. To address the engineering problem of the connection of carbonate rock pores formed by acid fracturing, considering the dynamic influence of acid on rocks during acid fracturing, this paper introduces phase field parameters to describe the acid-rock reaction, and proposes a simulation method of acid fracturing propagation based on the phase field method to simulate the connection of carbonate rock pores. Moreover, the paper performs a comparison on the fracture propagation characteristics of acid fracturing and slick water fracturing, and analyzes the influence of pore structure on acid fracturing propagation under different pore sizes and distributions. According to the simulation analysis, it can be found as follows. (1)Compared with normal hydraulic fractures, acid fracturing features have an increase in fracture width, and a decrease in fracture length and fracture propagation rate. Meanwhile, the rock on the fracture surface is corroded by acid, and the roughness of fracture surface increases significantly. (2)The pore structure induces the acid fracturing propagation, and when the fracture expands in the acidized area, the propagation rate is higher near the pores. (3)The larger the radius of the pores it is, the closer it is to the original propagation path of the fracture, the easier it is for the fracture to turn, and the easier it is for the fracture to have multiple pores connected, which can effectively increase the drainage area.

Key words: pore connection, acid fracturing, carbonate reservoir, fracture propagation, phase field method

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