地面井卸压的煤层气开发新模式  

A new CBM development mode:Surface well pressure relief

作　　者：李瑞[1,2,3] 卢义玉[1,2,3] 葛兆龙[1,2,3] 夏彬伟[1,2,3] 孙晗森 钟栋梁[1,3] 周雷[1,3] 周军平[1,3] 柳先锋 LI Rui;LU Yiyu;GE Zhaolong;XIA Binwei;SUN Hansen;ZHONG Dongliang;ZHOU Lei;ZHOU Junping;LIU Xianfeng(State Key Laboratory of Coal Mine Disaster Dynamic and Control//Chongqing University,Chongqing 400044,China;National&Local Joint Engineering Laboratory of Gas Drainage in Complex Coal Seam//Chongqing University,Chongqing 400044,China;School of Resources and Safety Engineering,Chongqing University,Chongqing 400044,China;CNOOC Research Institute Company Limited,Beijing 100028,China)

机构地区：[1]煤矿灾害动力学与控制国家重点实验室·重庆大学 [2]复杂煤气层瓦斯抽采国家地方联合工程实验室·重庆大学 [3]重庆大学资源与安全学院 [4]中海油研究总院有限责任公司

出　　处：《天然气工业》2022年第7期75-84,共10页Natural Gas Industry

基　　金：国家自然科学基金联合基金项目“煤层气及煤系气合采基础研究”(编号:U19B2009);国家杰出青年科学基金项目“水力化网格碎裂煤层增透理论与实践”(编号:51625401);重庆市自然科学基金项目“煤层气排采诱导有效应力变化的裂隙系统压降量化反演模型”(编号:cstc2020jcyj-bshX0035)。

摘　　要：中国煤层气资源丰富,分布广泛,勘探开发利用前景广阔。为了增强煤层气开发技术与我国复杂煤层气地质条件的匹配性,提高煤层气单井产量,在深入分析我国煤层气产量低的普遍性和差异性地质制约因素的基础上,对煤层气开发模式进行了研究,并提出了一种地面井卸压的煤层气开发新模式。研究结果表明:①地面排水降压采气开发模式对浅部硬煤层及含水煤层具有良好适应性,煤层气与煤炭协调开发模式仅适用于煤矿区煤层气开发;②基于煤层切割卸压原理,综合地面煤层气开发方式与矿井下瓦斯抽采方式,创新提出了地面井卸压的煤层气开发模式,该模式在地面进行定向钻孔并沿井筒创造卸压空间,充分改变地应力状态进而诱导岩层移动,改善储层渗流条件,提高储层压降传递效率,促进煤层气解吸、运移和产出;③地面井卸压开发模式可适用于松软破碎煤层以及高地应力的深部煤层气开发,具有良好的技术基础以及广泛地质适应性等优势;④在地面井卸压开发模式基础上,提出了针对我国不同煤层地质条件的煤层气开发模式布局。结论认为,地面井卸压的煤层气开发模式在定向井分段切割卸压开发煤层气以及大直径定向井卸压联合垂直井开发煤层气方面具有较好的应用前景,该煤层气开发模式有助力我国煤层气产业的发展。Coalbed methane(CBM)resources in China are rich and widely distributed with promising exploration,development and utilization prospect.To enhance the compatibility of CBM development technology with complex CBM geological conditions in China and improve the single-well CBM production rate,this paper deeply analyzes the universality and differentiated geological constraints of low CBM production rate in China.And based on this,CBM development modes are studied and a new CBM development mode of surface well pressure relief is put forward.And the following research results are obtained.First,the CBM development mode of surface drainage and depressurization is adaptable to shallow hard coal seams and water-bearing coal seams,and the CBM-coal coordinated development mode is only suitable for the CBM development in coal mine areas.Second,this new CBM development mode is innovatively put forward based on the principle of pressure relief by coal seam cutting,combined with the surface CBM development method and the subsurface mining gas extraction method.In this mode,directional drilling can be carried out on the ground and pressure relief space can be formed along the wellbore,which can sufficiently change the state of in-situ stress,so as to induce strata movement,increase reservoir permeability,improve transmission efficiency of reservoir pressure drop and promote CBM desorption,migration and production.Third,this mode is applicable to softbroken coal seams and deep coal seams with high in-situ stress,and it has the advantages of favorable technical basis and wide geological adaptability.Fourth,the layout scheme of CBM development modes for different geological conditions of coal seams in China is put forward based on this mode.In conclusion,this new CBM development mode has better application prospect in the CBM development of pressure relief by sectional cutting of directional well and the CBM development of pressure relief by large-diameter directional well combined with vertical well,and it is conducive to the deve

关 键 词：煤层气 复杂地质条件 地面井 地应力 卸压 储层压降 定向井 开发模式 

分 类 号：TE37[石油与天然气工程—油气田开发工程]