石油学报 ›› 2025, Vol. 46 ›› Issue (5): 938-952.DOI: 10.7623/syxb202505007

• 油田开发 • 上一篇    

低渗透非均质储层压驱注水井非稳态压力特征

崔传智1,2, 王俊康1,2, 吴忠维3, 李惊鸿1,2, 李静1,2, 钱银1,2   

  1. 1. 深层油气全国重点实验室(中国石油大学(华东)) 山东青岛 266580;
    2. 中国石油大学(华东)石油工程学院 山东青岛 266580;
    3. 长江大学石油工程学院 湖北武汉 430100
  • 收稿日期:2024-06-02 修回日期:2025-01-06 发布日期:2025-06-10
  • 通讯作者: 崔传智,男,1970年1月生,2005年获中国地质大学(北京)博士学位,现为中国石油大学(华东)石油工程学院教授,主要从事油气渗流理论与开发技术研究。Email:ccz2008@126.com
  • 基金资助:
    国家科技重大专项(2016ZX05011-002-003)和国家自然科学基金项目(No.51974343)资助。

Analysis of unsteady pressure characteristics of fracturing-flooding water injection wells in low-permeability heterogeneous reservoirs

Cui Chuanzhi1,2, Wang Junkang1,2, Wu Zhongwei3, Li Jinghong1,2, Li Jing1,2, Qian Yin1,2   

  1. 1. State Key Laboratory of Deep Oil and Gas, China University of Petroleum, Shandong Qingdao 266580, China;
    2. College of Petroleum Engineering, China University of Petroleum, Shandong Qingdao 266580, China;
    3. School of Petroleum Engineering, Yangtze University, Hubei Wuhan 430100, China
  • Received:2024-06-02 Revised:2025-01-06 Published:2025-06-10

摘要: 针对低渗透油藏压驱注水井关井压力降落测试曲线特征认识不清、储层非均质和裂缝属性难以确定的问题,基于黑油模型和位移不连续法,考虑启动压力梯度、应力敏感效应等储层特性,建立并求解了裂缝动态变化的压驱试井模型。将其应用于压驱典型地质模型,得到压驱试井的曲线特征。研究结果表明,压驱试井曲线可被分为6个典型流动阶段:井筒储集阶段、第一过渡流动阶段、裂缝流动阶段、第二过渡流动阶段、径向流动阶段和边界反映阶段;其中,裂缝流动阶段流动形态的差异主要与裂缝的长度、开度和导流能力有关;随着非均质储层中注水井附近渗透率逐渐降低,裂缝流动阶段经历了拟径向流、双线性流、线性流的转变。选取实际区块压驱注水井开展试井曲线拟合的反演结果表明,实例井位于渗透率渐变带中心,反演可得到该井的压驱裂缝半长和最高裂缝导流能力。

关键词: 低渗透油藏, 非均质储层, 压驱注水, 数值试井, 裂缝扩展, 位移不连续法

Abstract: This study aims to address the challenges in characterizing pressure falloff test curves during the shut-in period of fracturing-flooding water injection wells in low-permeability reservoirs, and the difficulty in determining reservoir heterogeneity and fracture properties. Based on the black-oil model and displacement discontinuity method (DDM), in combination with the reservoir characteristics such as threshold pressure gradient and stress sensitivity effects, a fracturing-flooding well testing model was developed and solved to account for dynamic fracture variations. Application of the model to a typical fracturing-flooding geological model revealed the fracturing-flooding well testing curve characteristics. The results show that the fracturing-flooding well testing curve can be divided into six typical flow stages: I. wellbore storage stage; Ⅱ. first transitional flow stage; Ⅲ. fracture-dominated flow stage; Ⅳ. second transitional flow stage; Ⅴ. radial flow stage; Ⅵ. boundary reflection stage. Among these, the differences in flow regime during Stage Ⅲ are mainly governed by the fracture length, aperture, and conductivity. With a gradual decrease in the permeability of heterogeneous reservoirs near the water injection well, Stage Ⅲ undergoes a transition from pseudo-radial flow to bilinear flow, and then to linear flow. A well testing curve fitting was performed on a fracturing-flooding water injection well in a target block, and the inversion results indicate that the well is located at the center of the permeability transition zone, with the fracturing-flooding fracture semi-length and maximum conductivity of the fracture being determined. This research offers technical support for the analysis of fracturing-flooding well testing curves and the formulation of post-stimulation development strategies.

Key words: low-permeability reservoirs, heterogeneous reservoirs, fracturing-flooding, numerical well testing, facture propagation, displacement discontinuity method

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