新疆石油地质 ›› 2022, Vol. 43 ›› Issue (1): 42-47.doi: 10.7657/XJPG20220106

• 油藏工程 • 上一篇    下一篇

前置蓄能压裂中的CO2在玛湖凹陷砾岩油藏中的作用

易勇刚1(), 黄科翔2, 李杰1, 牟善波3, 于会永1, 牟建业2(), 张士诚2   

  1. 1.中国石油 新疆油田分公司 工程技术研究院,新疆 克拉玛依 834000
    2.中国石油大学(北京) 石油工程学院,北京 102249
    3.新疆正通石油天然气股份有限公司,新疆 克拉玛依 834000
  • 收稿日期:2021-07-07 修回日期:2021-08-09 出版日期:2022-02-01 发布日期:2022-01-24
  • 通讯作者: 牟建业 E-mail:yiyg@petrochina.com.cn;moujianye@cup.edu.cn
  • 作者简介:易勇刚(1979-),男,四川仁寿人,高级工程师,稀油油藏提高采收率,(Tel)0990-6890596(E-mail) yiyg@petrochina.com.cn
  • 基金资助:
    国家油气重大专项(2017ZX05070)

Effect of CO2 Pre-Pad in Volume Fracturing of Conglomerate Reservoirs in Mahu Sag, Junggar Basin

YI Yonggang1(), HUANG Kexiang2, LI Jie1, MOU Shanbo3, YU Huiyong1, MOU Jianye2(), ZHANG Shicheng2   

  1. 1. Research Institute of Engineering Technology, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China
    2. School of Petroleum Engineering, China University of Petroleum, Beijing 102249, China
    3. Xinjiang Zhengtong Petroleum and Natural Gas Co., Ltd., Karamay, Xinjiang 834000, China
  • Received:2021-07-07 Revised:2021-08-09 Online:2022-02-01 Published:2022-01-24
  • Contact: MOU Jianye E-mail:yiyg@petrochina.com.cn;moujianye@cup.edu.cn

摘要:

准噶尔盆地玛湖凹陷砾岩储集层致密,渗流能力差,油藏产量递减快,稳产难度大。CO2前置蓄能压裂比水力压裂效果好,但对CO2与玛湖凹陷原油及储集层岩石间的作用规律尚未有系统研究。因此,对CO2水溶液的置换能力及其对岩心矿物的溶蚀、岩心孔隙度和渗透率的改变等进行了研究。对于玛湖凹陷砾岩油藏,CO2水溶液置换原油率高于纯CO2或水。玛湖凹陷砾岩油藏储集层碳酸盐岩含量较高,CO2水溶液的溶蚀作用明显,可提高储集层孔隙度和渗透率。实验结果表明,孔隙度平均增加了27%,渗透率平均增加了110%。在地层中,CO2水溶液优先溶蚀方解石,其次是白云石,对绿泥石也有一定溶蚀作用;矿物溶蚀主要发生在前5天,约5天后溶蚀量较少。

关键词: 玛湖凹陷, 砾岩油藏, CO2, 置换原油, 溶蚀, 孔隙度, 渗透率, 矿物成分, 前置蓄能压裂

Abstract:

The conglomerate reservoirs in the Mahu sag of Junggar basin are tight and the reservoir fluid has a poor flow capacity, resulting in rapid decline and unsteady production. Although the effect of CO2 pre-pad fracturing is better than that of hydraulic fracturing, no systematic study has been carried out on how CO2 affects the crude oil and reservoir rocks in Mahu sag. In this study, the displacement ability of CO2 aqueous solution, the dissolution of core minerals and the changes in core porosity and permeability are analyzed. It is found that in the Mahu conglomerate reservoirs, the crude oil displacing rate by CO2 aqueous solution is higher than that by pure CO2 or water. The Mahu conglomerate reservoir has a higher carbonate content, so CO2 aqueous solution can play a stronger dissolution role and increase the porosity and permeability of the reservoir. Experimental results show that the porosity has increased by 27% on average, and the permeability has increased by 110% on average. The injected CO2 aqueous solution prefers dissolving calcite first, then dolomite and last chlorite. Mineral dissolution mainly occurs in the first 5 days, and then becomes less after 5 days.

Key words: Mahu sag, conglomerate reservoir, CO2, crude oil displacement, dissolution, porosity, permeability, mineral composition

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