大宁—吉县区块深层煤岩气赋存产气特征与储量估算方法指标探讨  

Gas occurrence and production characteristics of deep coal measure gas and reserve estimation method and indicators in Daning-Jixian block

作　　者：李明宅 曹毅民 丁蓉 邓泽[2] 蒋轲 李永洲 姚晓莉 侯淞译 惠卉 孙晓光 伊伟 孙潇逸 曹昕欣 Li Mingzhai;Cao Yimin;Ding Rong;Deng Ze;Jiang Ke;Li Yongzhou;Yao Xiaoli;Hou Songyi;Hui Hui;Sun Xiaoguang;Yi Wei;Sun Xiaoyi;Cao Xinxin(PetroChina Coalbed Methane Company Limited;PetroChina Research Institute of Petroleum Exploration&Development;China United Coalbed Methane National Engineering Research Center Co.,Ltd.)

机构地区：[1]中石油煤层气有限责任公司 [2]中国石油勘探开发研究院 [3]中联煤层气国家工程研究中心有限责任公司

出　　处：《中国石油勘探》2024年第4期142-155,共14页China Petroleum Exploration

基　　金：中国石油天然气股份有限公司前瞻性基础性科技课题“国内已开发气田储采平衡分析与SEC增储技术研究”(2022DJ7902)。

摘　　要：深层煤岩气是煤层气勘探新领域,如何科学地估算深层煤岩气储量成为面临的新问题。从总结大宁—吉县区块深层煤岩气勘探开发成果出发,通过论证深层煤岩气的成藏特征、赋存模式、产气规律和生产特点,分析深层煤岩气独特的吸附气+游离气赋存特征、游离气→游离气+吸附气→吸附气的产气机制及其与浅—中浅层煤层气的明显差异,进而指出现行储量规范在估算方法、单元划分、估算参数、起算下限、资料录取等方面对估算深层煤岩气储量存在的不适应性。在上述研究的基础上,提出深层煤岩气储量估算建议:采用体积法和容积法两种方法估算储量,并根据游离气占比选择相应的估算方法;游离气需单独划分储量估算单元;夹矸起扣厚度为0.3~0.5m;R_(o)≤1.0%,煤层净厚度下限大于或等于1.0m;R_(o)>1.0%,煤层净厚度下限大于或等于0.8m;按深度段和井型分别确定单井产气量下限;勘探早期阶段,直井采收率为30%~45%,水平井采收率为35%~55%。研究为开展深层煤岩气勘探开发和储量估算提供了技术参考。The deep coal measure gas is a new field of CBM exploration,and the scientific estimation of deep coal measure gas reserves is a new challenge.By summarizing the exploration and development achievements in Daning-Jixian block,and analyzing gas accumulation characteristics,occurrence pattern,gas production laws and performance of deep coal measure gas,the unique occurrence characteristics of adsorbed gas+free gas,gas production mechanism of free gas→free gas+adsorbed gas→adsorbed gas,and its significant differences from shallow and medium-shallow coal measure gas have been studied.Furthermore,the inadaptability of the current reserve estimation standards for deep coal measure gas has been pointed out in terms of estimation methods,unit division,estimation parameters,threshold for calculation,and data collection.Based on the above research,the following suggestions are put forward for estimating deep coal measure gas reserves.The volume and volumetric methods can be used to estimate reserves,and the appropriate method should be selected based on the proportion of free gas;The reserve calculation units for free gas should be divided separately;The lower limit for coal gangue thickness deduction is 0.3-0.5 m;When R_(o)is less than 1.0%,the lower limit for net coal seam thickness should be greater than 1.0 m;When R_(o) is larger than 1.0%,the lower limit for net coal seam thickness should be greater than 0.8 m;The lower limit for single well gas production should be determined by well depth range and well type;In the early exploration stage,the recovery factor of vertical wells was 30%-45%,while that of horizontal wells was 35%-55%.This study provides technical references for the exploration and development,as well as reserve estimation of deep coal measure gas.

关 键 词：深层煤岩气 地质特征 吸附气 游离气 产气规律 储量参数 采收率 

分 类 号：TE122.2[石油与天然气工程—油气勘探]