中国深层煤层气地质特征与勘探实践

Geological features and exploration practices of deep coalbed methane in China

郭旭升 赵培荣 申宝剑 刘曾勤 罗兵 赵石虎 张嘉琪 贺甲元 付维署 魏海鹏 刘炯 陈新军 叶金诚

Xusheng GUO Peirong ZHAO Baojian SHEN Zengqin LIU Bing LUO Shihu ZHAO Jiaqi ZHANG Jiayuan HE Weishu FU Haipeng WEI Jiong LIU Xinjun CHEN Jincheng YE

中国深层煤层气资源丰富，近年勘探工作取得了积极进展，是非常规天然气的战略接替领域，但效益开发面临复杂的地质-工程挑战。本文研究了中国典型地区深层煤层气地质特征，总结了理论与技术研究进展，提出了深层煤层气的发展前景。研究结果表明：①与浅层对比，深层煤层气具有“非均质性强、游离气-吸附气双富、塑性强”的地质-工程特点。②深层中-低煤阶煤储集空间大，以原生植物组织孔为主，中-高煤阶煤微孔与裂隙发育，孔隙以有机质气孔为主，裂隙以割理和外生裂隙为主。③经过多年攻关，中国石化已经初步形成了深层煤层气选区评价、甜点预测、水平井钻井与有效支撑压裂改造技术系列，为深层煤层气的勘探突破提供了有效支撑。④建议进一步加强深层煤层气富集规律与“甜点”及开发技术政策与排采规律研究，研发薄煤层水平井优快钻完井与压裂改造降本增效技术。

China boasts abundant deep coalbed methane （CBM） resources. Positive progress in the exploration in recent years has established CBM as a strategic replacement for current unconventional natural gas in the future. However， the commercial exploitation of deep CBM faces challenges of complex geological and engineering conditions. In this study， we investigate the geology of deep CBM in typical regions across China and review advances in relevant theoretical and technical study， proposing the prospects for the exploration and production of deep CBM. The results indicate that deep CBM reservoirs exhibit the geological and engineering characteristics of strong heterogeneity， enrichment in both free and adsorbed gas， and high plasticity compared to their shallow counterparts. Deep medium- to low-rank coal reservoirs provide substantial storage space dominated by primary plant tissue pores. In contrast， deep medium- to high-rank coal reservoirs contain micropores and fissures， with the former dominated by organic pores and the latter consisting primarily of cleats and exogenetic fractures. Over years of addressing technological challenges， SINOPEC has preliminarily developed a series of technologies for the selection and assessment of deep CBM target areas， sweet spot prediction， horizontal well drilling， and hydraulic fracturing with fractures effectively propped， which serve to provide effective support for breakthroughs achieved in deep CBM exploration. It is recommended to focus on the accumulation patterns， sweet spot identification， production technologies and policies， and production rules of deep CBM in future study. Additionally， it is advisable to develop efficient drilling and completion technologies for horizontal wells in thin coal seams， along with technologies for fracturing with reduced cost and enhanced efficiency for reservoir stimulation.

10.11743/ogg20240601