沁水盆地南部深层高阶煤层气成藏特征  

Gas accumulation characteristics of high-rank coal in deep formations in the southern Qinshui Basin

作　　者：杨延辉 张鹏豹 刘忠 张永平 肖宇航 韩峰 赵良言 王小玄 杨洲鹏 白晓斌 刘振兴 胡家华 Yang Yanhui;Zhang Pengbao;Liu Zhong;Zhang Yongping;Xiao Yuhang;Han Feng;Zhao Liangyan;Wang Xiaoxuan;Yang Zhoupeng;Bai Xiaobin;Liu Zhenxing;Hu Jiahua(PetroChina Huabei Oilfield Company;Hebei Province Key Laboratory of Efficient Development of Coalbed Methane Resources;School of Energy Resources,China University of Geosciences(Beijing);PetroChina Research Institute of Petroleum Exploration&Development)

机构地区：[1]中国石油华北油田公司,062550 [2]河北省煤层气资源高效开发重点实验室 [3]中国地质大学(北京)能源学院 [4]中国石油勘探开发研究院

出　　处：《中国石油勘探》2024年第5期107-119,共13页China Petroleum Exploration

基　　金：中国石油华北油田公司重大科技专项“煤层气高效上产勘探开发关键技术攻关与应用”(2024HBYTZX05)。

摘　　要：沁水盆地南部中浅层已经建成年产能力达26×10^(8)m^(3)的煤层气田,但深层煤层气勘探程度较低,地质认识不足。为了深化区域深层煤层气成藏特征研究,根据研究区探井钻探、分析化验及试采资料,从煤储层特征、热演化及含气特征、保存条件、温压特征等4个方面开展了深层煤层气成藏特征研究。结果表明:(1)3号煤沉积稳定,总厚度为4.0~7.3m,具有镜质组含量高、灰分低、裂隙发育的有利条件;(2)3号煤R_(o)为2.41%~3.03%,为高煤阶,吸附能力强,吸附含气量大于20m^(3)/t;(3)3号煤排采水矿化度大于4000mg/L,水型为NaHCO_(3),处于弱径流环境。煤层气藏具有偏低温低压的特征,表明深层煤层气藏遭受一定的破坏,未明显影响深层吸附气,但是对游离气成藏不利。研究区深层煤层气相对于已评价建产的斜坡带中浅层煤层气成藏条件更加有利,深层3号煤资源量估算1200×10^(8)m^(3),勘探开发潜力好。A shallow-medium coalbed methane(CBM)field has been established in the southern Qinshui Basin with an annual production capacity of 26×10^(8) m^(3).However,the exploration of deep CBM is at a low level,and there is insufficient geological understanding.By using drilling,lab test,and trial production data of exploration wells in the study area,accumulation characteristics of deep CBM have been analyzed from four aspects,i.e.,coal reservoir characteristics,thermal evolution and gas-bearing property,preservation conditions,and temperaturepressure characteristics.The study results show that:(1)The No.3 coal seam is consistent,with a total thickness of 4.0-7.3 m,which has the favorable conditions of high vitrinite content,low ash content,and well-developed fissures;(2)R_(o) of the No.3 coal ranges in 2.41%-3.03%,showing a high-rank coal,which has strong adsorption capacity,with an adsorbed gas content of higher than 20 m^(3)/t;(3)The salinity of the produced water from No.3 coal is greater than 4000 mg/L,showing a NaHCO_(3) water type,and it is in a weak radial flow environment.The deep CBM reservoir has the characteristics of slightly low temperature and low pressure,indicating that it has suffered certain damage,which insignificantly affected the adsorbed gas,but was not conducive to the accumulation of free gas.The conclusion suggests that the accumulation conditions for deep CBM in the study area are more favorable than those of the shallow-medium CBM,which has already been appraised and developed in the slope zone.The estimated CBM resources of the deep No.3 coal are 1200×10^(8) m^(3),indicating good potential for CBM exploration and development.

关 键 词：沁水盆地南部 深层煤层气 成藏特征 成藏模式 资源潜力 

分 类 号：TE122.1[石油与天然气工程—油气勘探]