贵州省盘关向斜煤层气储层地质特征及开发效果评价

Geological characteristics and development effect evaluation of coalbed methane reservoirs in Panguan syncline, Guizhou Province

胡海洋 阳富芹 陈捷 娄毅 万玉亭

HU Haiyang YANG Fuqin CHEN Jie LOU Yi WAN Yuting

1. 贵州省煤层气页岩气工程技术研究中心, 贵阳 550081; 2. 贵州省煤田地质局 地质勘察研究院, 贵阳 550081; 3. 贵州盘江煤层气开发利用有限责任公司, 贵阳 550081; 4. 中国石油大学(华东) 石油工程学院, 山东 青岛 266000

1. Guizhou Research Center of Shale Gas and CBM Engineering Technology, Guiyang, Guizhou 550081, China; 2. Geological Exploration Research Institute, Guizhou Bureau of Coal Geological Exploration, Guiyang, Guizhou 550081, China; 3. Guizhou Panjiang Coalbed Methane Development and Utilization Co., Ltd., Guiyang, Guizhou 550081, China; 4. School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, Shandong 266000, China

贵州省上二叠统龙潭组煤层多，煤层气资源丰度高，具备煤层气开发的资源基础，但煤层渗透率较低，影响气、水产出，需探索适应贵州省低渗、多煤层条件下的煤层气开发关键技术。根据盘关向斜煤储层地质特征及煤层气井工程资料，从地质、压裂、排采指标3个维度开展研究分析，总结低渗、多煤层的煤层气开发技术。盘关向斜工程实践表明：①该向斜12#、18#煤层合层开发煤层气，渗透率、储层温度、破裂压力、每米煤层的加液量及加砂量、压降速率、提产速率对煤层气井产气的影响较大；②提高每米煤层的加液量及加砂量指标，能够显著提高压裂改造后的储层渗透率，YP-1井改造后渗透率达到64.158×10-3 μm2，提高1 304倍；③控制合适的压降速率、提产速率能够提高煤层气井的压裂液返排率及扩大压降漏斗半径，YP-1井排采210 d后压裂液累计返排率达到82.53%，产水半径达到压裂影响半径的91%，对扩大有效解吸半径及提高产气效果有利。针对盘关向斜低渗、多煤层的地质条件，建议采取“选层射孔、分段压裂、合层排采”的工艺技术进行煤层气开发，从而提高煤层气开发的地质及工程潜力。

The Upper Permian Longtan Formation in Guizhou Province contains multiple coal seams with abundant coalbed methane (CBM) resources, providing a solid base for CBM development. However, the low permeability of the coal seams hinders gas and water production, necessitating the development of key technologies for CBM development under conditions of low permeability and multiple coal seams in Guizhou. Based on the geological characteristics of coal reservoirs in the Panguan syncline and CBM well engineering data, the study analyzed geological, fracturing, and drainage and production parameters, and summarized development technologies for low-permeability and multi-seam CBM reservoirs. Engineering practices in Panguan syncline show that: (1) For commingled development of coal seams 12# and 18# in the syncline, factors such as permeability, reservoir temperature, fracture pressure, liquid and sand addition per meter of coal seam, pressure drop rate, and production enhancement rate significantly influence gas production of CBM wells. (2) Increasing the liquid and sand addition per meter of coal seam can significantly increase the reservoir permeability after fracturing. The permeability of well YP-1 after fracturing reached 64.158×10-3 μm2, 1 304 times higher than before. (3) Controlling pressure drop rate and production enhancement rate to appropriate levels can improve the fracturing fluid flowback rate and expand the pressure drop funnel radius of CBM wells. The cumulative fracturing fluid flowback rate of well YP-1 reached 82.53% after 210 days of drainage and production, with the water production radius reaching 91% of the fracturing influence radius. This helps to expand effective desorption radius and improve the effectiveness of gas production. For the Panguan syncline with low permeability and multiple coal seams, the study suggests adopting the technical approach of “selected layer perforation, segmented fracturing, and commingled drainage and production” to improve the geological and engineering potential of CBM development.

贵州省科技计划项目(黔科合支撑[2024]一般054，黔科合战略找矿[2022]ZD001-03，黔科合平台人才-CXTD[2022]016)联合资助。

https://doi.org/10.11781/sysydz2025010213