鄂尔多斯盆地延川南区块深部地应力状态及其对煤层气开发效果的影响  

Stress state of deep seam and its influence on development performance of CBM wells in South Yanchuan Block,Odors Basin

作　　者：赵景辉[1] 高玉巧[1] 陈贞龙[1] 郭涛[1] 高小康[1] ZHAO Jinghui;GAO Yuqiao;CHEN Zhenlong;GUO Tao;GAO Xiaokang(Institute of Exploration&Development,Sinopec East China Oil&Gas Company,Nanjing 210011,Jiangsu,China)

机构地区：[1]中国石化华东油气分公司勘探开发研究院,江苏南京210011

出　　处：《中国地质》2021年第3期785-793,共9页Geology in China

基　　金：中国石化科技部项目(P19019-4);国家科技重大专项(2011ZX05035006)联合资助。

摘　　要：延川南区块煤储层埋深在700~1500 m,多数深于900 m。基于该区块压裂施工压降数据,计算最大、最小水平主应力和垂向应力,划分储层地应力类型,分析了地应力及其类型对渗透率和压裂效果的影响。结果表明,研究区整体处于拉张状态,最大、最小水平主应力和垂向应力与埋深呈正相关线性关系。地应力类型以Ⅰa类为主,Ⅲ类其次,Ⅱ类最少。Ⅰa类地应力储层以垂直裂缝为主,裂缝指数最低,但应力敏感性弱,应力敏感性系数仅为0.479,且压裂缝半长最短,产气量最低,产水量最高。Ⅱ类地应力储层主次裂缝宽分别为16μm和11μm,宽度最大,但储层应力敏感性最强。压裂以水平裂缝为主,裂缝指数最高,且压裂缝最长,改造效果最好,产气量最高。Ⅲ类地应力储层裂缝复杂,渗透性和应力敏感性居中,压裂缝长居中,但产量相对较低,不能实现效益开发。The buried depth of the coal seams of South Yanchuan block is between 700 m and 1500 m.And for the most area,the depth is deeper than 900 m.In order to clarify the in-situ stress state of deep coal-bed methane reservoir and its influence on the development of CBM wells,the maximum and minimum horizontal principal stress and the vertical stress are calculated based on the pressure drop data of hydraulic fracturing.The results show that the whole area is in the state of tension.The maximum horizontal principal stress,the minimum horizontal principal stress and the vertical stress are positively correlated with the buried depth.The type of the ground stress is mainly typeⅠa,followed byⅢtype andⅡtype.The reservoir with typeⅠa ground stress is dominated by vertical fractures with the lowest fracture index.However,the stress sensitivity is weak,and the stress sensitivity coefficient is only 0.479.The main and secondary fractures of typeⅠstress reservoir are 16μm and 11μm respectively,with the largest width and the strongest reservoir stress sensitivity.TypeⅠfractures are mainly horizontal fractures,with the highest fracture index,the longest compression fracture,the best reconstruction effect and the highest gas production.Reservoirs with typeⅢin-situ stress develop complex fractures,with medium permeability,stress sensitivity and hydraulic fracture length.However,the production for typeⅢis relatively low,and cannot achieve economic development.

关 键 词：深部煤层 煤层气 地应力 压裂效果 渗透率 油气地质调查工程 延川区块 鄂尔多斯盆地 

分 类 号：TE112.2[石油与天然气工程—油气勘探]