煤炭工程 ›› 2026, Vol. 58 ›› Issue (5): 117-124.doi: 10.11799/ce202605015

• 生产技术 • 上一篇    下一篇

基于油管-环空联合注入的软硬复合煤层水平井分段压裂强化抽采技术研究

徐建军,许耀波   

  1. 中煤科工西安研究院(集团)有限公司,陕西 西安 710054

  • 收稿日期:2025-06-23 修回日期:2025-08-07 出版日期:2026-05-15 发布日期:2026-05-27
  • 通讯作者: 徐建军 E-mail:782356383@qq.com

Research on enhanced gas extraction technology through multi-stage fracturing in soft-hard interbedded coal seams using tubing-casing annulus co-injection #br#

  • Received:2025-06-23 Revised:2025-08-07 Online:2026-05-15 Published:2026-05-27

摘要:

针对我国软硬复合煤层渗透性差异显著、常规压裂技术适应性差导致的煤层气抽采效率低等问题,以晋城矿区3号软硬煤复合层为对象,提出“地质-工程一体化”开发理念,创新研发套管外不固井水平井分段压裂技术。通过“油管+环空”双通道联合注入压裂工艺(排量8.0 ~9.0m3/min,加砂强度6~8m3/m),结合自主研发的扩张式封隔器(耐压70 MPa)、 防砂水力锚(抗拉强度>200kN)及大排量水力喷射-压裂联作工具,形成“射孔-压裂”联作模式,实现软硬煤层的分段均衡改造。现场试验表明,单井日产气量突破5000m3,软煤层产气贡献率提升至35%,抽采2a后瓦斯含量降幅达24.2%,施工成本降低10万元/段,效率提升30%。该技术有效解决了井壁失稳、煤粉堵塞等难题,显著提升了泄压体积与抽采效率,为煤矿瓦斯灾害防治、煤层气规模化开发及“双碳”目标下的绿色矿山建设提供了技术支撑。

关键词:

煤层气, 软硬复合煤层, 水平井分段压裂, 油管-环空联合注入, 瓦斯抽采效率

Abstract:

Aiming at the challenges of low coalbed methane (CBM) extraction efficiency caused by significant permeabil-ity differences in soft-hard interbedded coal seams and poor adaptability of conventional fracturing technolo-gies in China, this study focuses on the No. 3 soft-hard interbedded coal seam in the Jincheng mining area. A "geology-engineering integration" development concept is proposed, and an innovative staged fracturing tech-nology for horizontal wells with uncemented casing outside the coal seam is developed. By adopting a tub-ing-annulus co-injection fracturing process (injection rate: 8.0–9.0 m3/min, proppant concentration: 6–8 m3/m), combined with self-developed expandable packers (pressure resistance: 70 MPa), sand-control hydraulic an-chors (tensile strength >200 kN), and high-displacement hydraulic jetting-fracturing integrated tools, a "perfo-ration-fracturing" collaborative mode is established to achieve balanced staged stimulation of soft and hard coal layers. Field tests demonstrate that the single-well daily gas production exceeds 5,000 m3, the gas contri-bution rate of soft coal seams increases to 35%, and the gas content reduction reaches 24.2% after two years of extraction. Additionally, the construction cost is reduced by 100,000 yuan per stage, with a 30% improvement in efficiency. This technology effectively resolves issues such as wellbore instability and coal fines blockage, significantly enhances pressure relief volume and extraction efficiency, and provides technical support for coal mine gas hazard prevention, large-scale CBM development, and green mine construction under the “du-al-carbon” goal.

中图分类号: