石油学报 ›› 2019, Vol. 40 ›› Issue (8): 965-974.DOI: 10.7623/syxb201908007

• 油田开发 • 上一篇    下一篇

压裂支撑剂在迂曲微裂缝中输送与分布规律

徐加祥1,2,3, 丁云宏1, 杨立峰2,3, 刘哲2,3, 高睿2,3, 王臻2,3   

  1. 1. 中国石油勘探开发研究院 北京 100083;
    2. 中国石油勘探开发研究院压裂酸化技术服务中心 河北廊坊 065007;
    3. 中国石油天然气集团公司油气藏改造重点实验室 河北廊坊 065007
  • 收稿日期:2018-08-22 修回日期:2019-05-29 出版日期:2019-08-25 发布日期:2019-08-28
  • 通讯作者: 杨立峰,男,1979年9月生,2002年获石油大学(华东)学士学位,2005年获中国石油大学(北京)硕士学位,现为中国石油勘探开发研究院高级工程师,主要从事储层增产改造技术的研究工作。Email:yanglf1979@163.com
  • 作者简介:徐加祥,男,1991年6月生,2014年获中国石油大学(华东)学士学位,2017年获中国石油大学(华东)硕士学位,现为中国石油勘探开发研究院博士研究生,主要从事储层增产改造技术的研究工作。Email:shigong101121@163.com
  • 基金资助:

    国家科技重大专项"致密油储层高效体积改造技术"(2016ZX05046-004)资助。

Transportation and distribution laws of proppants in tortuous micro-fractures

Xu Jiaxiang1,2,3, Ding Yunhong1, Yang Lifeng2,3, Liu Zhe2,3, Gao Rui2,3, Wang Zhen2,3   

  1. 1. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China;
    2. Fracturing and Acidizing Technology Service Center, PetroChina Research Institute of Petroleum Exploration and Development, Hebei Langfang 065007, China;
    3. CNPC Key Laboratory for Reformation of Oil and Gas Reservoirs, Hebei Langfang 065007, China
  • Received:2018-08-22 Revised:2019-05-29 Online:2019-08-25 Published:2019-08-28

摘要:

支撑剂在水力裂缝中的分布是影响压裂井产能的重要因素。通过对任意长度、孔隙度、迂曲度和方位角微裂缝的二维重构,利用COMSOL Multiphysics中的自由与多孔介质流动耦合模型,对压裂液在微裂缝中流动及向基质中滤失的情况进行模拟,在考虑支撑剂与压裂液相互作用的基础上,分析了支撑剂颗粒在输送过程中的受力情况,研究了不同砂比和支撑剂密度的情况下,支撑剂在迂曲微裂缝中的分布。研究结果表明,与规则裂缝相比,由于迂曲微裂缝壁面不规则,支撑剂不会均匀推进;在高砂比情况下,支撑剂大部分堆积在迂曲裂缝端部,无法有效支撑深部裂缝;降低砂比可以有效改善单条裂缝的支撑剂分布;不同砂比和支撑剂密度的组合可以改善相交裂缝的支撑剂分布,但是对于单条裂缝的作用不明显。

关键词: 迂曲微裂缝, 流固耦合, 压裂液滤失, 支撑剂分布, 粒子追踪

Abstract:

The distribution of proppants in hydraulic fractures has great influences on the productivity of the fractured reservoir. Using the MATLAB program self-developed by authors, this study achieves the two-dimensional reconstruction of any micro-fracture with different arbitrary length, porosity, tortuosity and azimuth. Then the free and porous medium flow coupling model in COMSOL Multiphysics is applied to simulate the flow of fracturing fluid in micro-fractures and filtering into matrix. Based on the consideration of the interaction between proppants and fracturing fluid, this paper analyzes the force condition of proppant particles during the transport process, and studies the distribution of proppant in the tortuous micro-fractures under different sand ratios and proppant densities. The results show that compared with the regular fractures, the proppant cannot be uniformly propelled due to the irregular wall surface of tortuous micro-fractures. In the case of high sand ratio, most of the proppant accumulates at the entrance of tortuous fracture, unable to effectively support the deep part of fractures. The reduction of sand ratio can effectively improve the proppant distribution in single fracture; the combination of different sand ratios and proppant density can improve the proppant distribution in intersecting fractures, but has no obvious effect on a single fracture.

Key words: tortuous micro-fractures, fluid-solid coupling, fracturing fluid loss, proppant distribution, particle tracing

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