特种油气藏 ›› 2026, Vol. 33 ›› Issue (2): 72-78.DOI: 10.3969/j.issn.1006-6535.2026.02.008

• 油藏工程 • 上一篇    下一篇

页岩油藏CO2前置压裂对裂缝网络的影响

崔传智1,2, 钱银1,2, 吴忠维3, 王俊康1,2, 张世明4, 吕琦4, 程紫燕4   

  1. 1.中国石油大学(华东)石油工程学院,山东 青岛 266580;
    2.中国石油大学(华东)深层油气全国重点实验室,山东 青岛 266580;
    3.长江大学石油工程学院,湖北 武汉 430100;
    4.中国石化胜利油田分公司,山东 东营 257015
  • 收稿日期:2025-02-20 修回日期:2026-01-14 发布日期:2026-07-30
  • 作者简介:崔传智(1970—),男,教授,博士生导师,1993年毕业于石油大学(华东)油藏工程专业,2005年毕业于中国地质大学(北京)矿产普查与勘探专业,获博士学位,现从事油气渗流理论、油气田开发技术方面的教学与研究工作。
  • 基金资助:
    国家自然科学基金“致密油藏多段压裂水平井时空耦合流动模拟及参数优化方法”(51974343);中国石化科技部科研项目“东营凹陷页岩油立体开发优化设计关键技术”(P23026)

Effect of CO2 pre-fracturing on fracture networks in shale oil reservoirs

CUI Chuanzhi1,2, QIAN Yin1,2, WU Zhongwei3, WANG Junkang1,2, ZHANG Shiming4, LYU Qi4, CHENG Ziyan4   

  1. 1. School of Petroleum Engineering,China University of Petroleum(East China),Qingdao,Shandong 266580,China;
    2. State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao,Shandong 266580,China;
    3. School of Petroleum Engineering,Yangtze University,Wuhan,Hubei 430100,China;
    4. Shengli Oilfield Company,Sinopec, Dongying,Shandong 257015,China
  • Received:2025-02-20 Revised:2026-01-14 Published:2026-07-30

摘要: 为研究页岩油藏CO2前置压裂对裂缝网络规模与形态的影响,结合东营凹陷页岩油藏储层地质特征,应用Petrel软件建立了包含天然裂缝的三维地质模型,将裂缝网络体积和裂缝网络复杂度作为储层压裂改造效果评价指标,分析了不同天然裂缝密度、水平应力差下前置CO2注入量对裂缝网络体积和复杂度的影响。研究表明:天然裂缝密度对裂缝网络体积影响较小,CO2注入量增加使裂缝网络体积先减小后增大,当单段CO2注入量超过约120 t时,其低黏度、高扩散性的优势才得以体现,裂缝网络体积快速增大。天然裂缝密度越高,裂缝网络复杂度也越高;对于天然裂缝发育的储层,CO2注入量增加使裂缝网络复杂度先增大后趋于平缓。水平应力差对裂缝网络复杂度影响显著,低应力差条件下更容易形成分支缝。该研究可为页岩油储层水平井CO2前置压裂设计提供理论指导。

关键词: CO2前置压裂, 页岩油藏, 天然裂缝, 水平应力差, 裂缝网络体积, 裂缝网络复杂度

Abstract: To investigate the influence of CO2 pre-fracturing on the scale and morphology of fracture networks in shale oil reservoirs,a three-dimensional geological model that includes natural fractures was constructed using Petrel software,based on the reservoir characteristics of a shale oil formation in the Dongying Sag.By using the fracture network volume and network complexity as evaluation indices of fracturing effectiveness,analysis was made on the impact of CO2 pre-injection volumes on these indices under different natural fracture densities and horizontal stress differences.The results showed that natural fracture density had little effect on fracture network volume;increasing CO2 injection volume first reduced and then increased the network volume,with a sharp increase occurring once the CO2 injected per stage exceeded about 120 t which point the low viscosity and high diffusivity of CO2 dominated.Higher natural fracture density led to higher network complexity;in reservoirs with well-developed natural fractures,increasing CO2 injection caused network complexity to rise and then level off.Horizontal stress difference significantly affected network complexity:branching fractures formed more readily under low stress-difference conditions.This study provides theoretical guidance for designing horizontal-well CO2 pre-fracturing in shale oil reservoirs.

Key words: CO2 pre-fracturing, shale oil reservoir, natural fracture, horizontal stress difference, fracture network volume, fracture network complexity

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