沁水盆地寿阳区块煤层气井产水差异性原因分析及有利区预测  

Reasons for water production difference of CBM wells in Shouyang Block, Qinshui Basin, and prediction on favorable areas

作　　者：王金[1] 康永尚[1,2] 姜杉钰 张守仁[3,4] 叶建平[3,4] 吴见[3,4] 张兵[3,4] 郭明强[3,4] 

机构地区：[1]中国石油大学(北京)地球科学学院 [2]油气资源与探测国家重点实验室 [3]中海石油(中国)有限公司非常规油气分公司 [4]中联煤层气有限责任公司

出　　处：《天然气工业》2016年第8期52-59,共8页Natural Gas Industry

基　　金：国家科技重大专项"深煤层煤层气开发技术研究及装备研制"(编号:2011ZX05042)

摘　　要：沁水盆地寿阳区块多数煤层气井在排采过程中呈现出"高产水、低产气"的特点,较高的产水量严重制约了煤层气单井产能。为此,基于该区64口煤层气井的排采动态资料和相关的地质、钻井及压裂资料,从断裂构造、压裂缝类型和煤层顶底板岩性组合三方面综合分析了煤层气井产水差异性的原因,并据此提出了"避水采气"层次分析方法,预测了该区"避水采气"的有利区。研究认为,该区煤层气井产水差异性主要存在两大原因:(1)部分煤层气井位于断层附近,断层沟通了煤层顶底板的砂岩含水层,导致单井产水量较高;(2)区域地应力类型决定了该区煤层在压裂过程中会产生垂直压裂缝,其压穿岩性组合类型较差的煤层顶底板,从而沟通含水层导致单井产水量较高。结论认为:(1)煤层气生产过程中应进行"避水采气"有利区预测,其层次分析步骤为"一看断裂构造,二看应力类型,三看岩性组合";(2)该区块西部、东北部和中北部为煤层气开发的"避水采气"有利区。The CBM （coalbed methane） wells in Shouyang Block, Qinshui Basin, are mostly characterized by ＂high water yield but low gas output＂ in the process of drainage gas recovery. High water production restricts single-well CBM production. Therefore, 64 wells in Shouyang Block were investigated in terms of their dynamic production performance, geologic, drilling and fracturing data. Then the reasons for water production difference of CBM wells were comprehensively analyzed from the aspects of faulted structure, hydraulic fracture type and lithological combination types of coal roof and floor. Finally, the analytical hierarchy process of ＂water evading and gas producing＂ was accordingly put forward, and the favorable ＂water-evading and gas-producing＂ areas were predicted. It is shown that there are two key reasons for water production difference of CBM wells in Shouyang Block. First, some CBM wells are located near faults, which connect the sandstone aquifers between coal roof and floor, leading to higher single-well water production. And second, the region- al ground stress in Shouyang Block determines that vertical hydraulic fractures will be generated in the process of coalbed fracturing in this block and they penetrate the coal roof and floor where lithological combinations are poor, so aquifers are connected and single-well water production is increased. It is recommended to predict favorable ＂water evading and gas producing＂ areas in the process of CBM production. And the analytical hierarchy process should be performed subsequently based on faulted structure, stress type and lithological combination. It is concluded that the favorable ＂water-evading and gas-producing＂ areas for CBM development are located in the western, northeastern and north central Shouyang Block.

关 键 词：沁水盆地 寿阳区块 煤层气 产水差异性 断裂构造 压裂缝类型 岩性组合 有利区预测 

分 类 号：TE37[石油与天然气工程—油气田开发工程]