埋深对深部煤层气储层物性及开发效果的影响--以鄂尔多斯盆地东南缘延川南区块为例  

Effect of burial depth on reservoir petrophysical properties and development performance of deep coalbed methane reservoirs:A case of Yanchuannan Block in southeastern margin of Ordos Basin

作　　者：赵景辉[1] ZHAO Jinghui(Institute of Exploration&Development,SINOPEC East China Oil&Gas Company,Nanjing City,Jiangsu Province,210000,China)

机构地区：[1]中国石化华东油气分公司勘探开发研究院,江苏南京210000

出　　处：《油气地质与采收率》2022年第3期62-67,共6页Petroleum Geology and Recovery Efficiency

基　　金：中国石化科技部项目“延川南深层煤层气稳产技术研究”(P19019-4)和“低压煤系气藏地质工程一体化高效开发技术”(P20074-1)。

摘　　要：基于鄂尔多斯盆地东南缘延川南区块室内实验数据和开发数据,研究埋深对煤层气储层物性、开发效果及煤层气富集高产的影响,提出了深部煤层气储层富集高产区定量评价指标和计算公式。结果表明:埋深越大,煤层气越富集,研究区最大镜质组反射率随着埋深增加而增大,古地温随埋深增加持续升高,因此生烃能力随着埋深(古地温)增加持续增加,再加上高温热液烘烤,该区古地温明显高于正常值,利于煤层气大量生成,导致研究区CH_(4)含量随埋深增加而增加。埋深对煤层气井产量具有双重影响,储层渗透率随埋深增加呈负指数降低,当埋深达到1500 m左右时,渗透率降至约为0.1 mD;但吸附时间随埋深增加而降低,即埋深越大,解吸效率越高,这是深部煤层气开发的有利因素。利用含气量、渗透率和吸附时间3个参数计算的产气指数表明,其与单井产量具有良好的相关性,能够对研究区煤层气富集高产区进行有效预测;研究区产气指数随埋深先增加后降低,在埋深为1100 m附近达到最高,为最有利开发区。Based on the laboratory test and development data of Yanchuannan Block in the southeastern margin of the Or⁃dos Basin,this paper studied the role of burial depth in the reservoir petrophysical properties,development performance,as well as the enrichment and production of coalbed methane reservoirs.The quantitative evaluation index and calculation for⁃mula were put forward for the enrichment and high-production zone of deep coalbed methane reservoirs.The results show that the deeper burial depth can lead to the more enriched coalbed methane and the greater maximum vitrinite reflectance.It indicates that the paleo-geotemperature continues to increase with the greater burial depth,resulting in the constant growth in hydrocarbon generation capacity.Coupled with the high-temperature hydrothermal baking,the paleo-geotemper⁃ature is rather higher than the normal value,leading to massive coalbed methane;thus the CH4 content tends to be higher with the greater burial depth in the study area.Burial depth has a dual influence on the production of coalbed methane wells.On one hand,an exponential decrease is observed in the reservoir permeability with the greater burial depth,down to about 0.1 mD at 1500 m around.On the other hand,however,the adsorption time declines with the greater burial depth,namely that the desorption efficiency grows,which is favorable for the development of deep coalbed methane reservoirs.Based on the gas content,permeability and adsorption time,the calculation formula for the gas production index is devised,and this index has a good correlation with the single well production.The enrichment and high-production zone of coalbed methane in the study area can be correctly predicted.The gas production index of the study area rises first and then drops with the greater burial depth.It reaches the highest at the burial depth around 1100 m,revealing the most favorable devel⁃opment zone in the study area.

关 键 词：煤层气 储层物性 富集高产区 开发效果 鄂尔多斯盆地 

分 类 号：TE122[石油与天然气工程—油气勘探]