考虑孔隙压缩及煤基质收缩效应的煤层气井产能预测模型及影响因素  

Coalbed methane well productivity prediction model considering pore compressibility and coal matrix shrinkage effect and influencing factors analysis of well productivity

作　　者：李福堂[1] 黄卫 陈海霞[1] 仲学哲 LI Futang;HUANG Wei;CHEN Haixia;ZHONG Xuezhe(Exploration and Development Reasearch Institute of PetroChina Jidong Oilfield Company,Tangshan 063000,China)

机构地区：[1]中国石油冀东油田公司勘探开发研究院,河北唐山063000

出　　处：《大庆石油地质与开发》2023年第5期168-174,共7页Petroleum Geology & Oilfield Development in Daqing

摘　　要：煤层气井产能预测中仅考虑应力敏感效应而忽略基质孔隙收缩效应导致产能评价误差较大。在分析非达西作用、煤基质收缩作用的基础上,建立了考虑孔隙压缩及煤基质收缩效应的煤层气产能预测模型。结果表明:考虑非达西效应的煤层气井产量明显低于不考虑非达西效应的产量,并且随着生产压差的增大,二者之间的产量差异逐渐扩大;煤层气井井底流压的减小会导致生产压差增加,相应煤层气井的产量增大幅度下降;无论考虑非达西效应与否,随着生产压差的增大,产量差值逐渐增大;随着孔隙压缩系数的增大,煤层相对渗透率逐渐降低,并且相对渗透率与生产压差呈线性关系。实例验证表明,新的产能预测模型比Eclipse模型更接近实际产气量。研究成果可为煤层气井产能预测影响因素分析提供理论指导与技术参考。Coalbed methane well productivity prediction only considering stress sensitivity effect while ignoring ma-trix pore shrinkage effect result in much error in productivity evaluation.Based on analysis of non-Darcy effect and coal matrix shrinkage,coalbed methane productivity prediction model is established considering pore compressibili-ty and coal matrix shrinkage.The results show that coalbed methane well production considering non-Darcy effect is significantly lower than that without considering non-Darcy effect,and the production difference between them in-creases gradually with the increase of production pressure difference.Bottom hole pressure decrease of coalbed methane well causes increase of production pressure difference and reduction of production increase range of corre-sponding coalbed methane well.Whether taking non-Darcy effect into account or not,production difference increas-es gradually as production pressure difference increases.With the increase of pore compressibility coefficient,rela-tive permeability of coal bed decreases gradually,appearing as linear relationship with production pressure differ-ence.Case verification shows that productivity prediction by the new mode is closer to actual gas production than Eclipse model.The research provides theoretical guidance and technical reference for analysis of influencing factors of coalbed methane well productivity prediction.

关 键 词：孔隙压缩 煤基质收缩 非达西效应 产能方程 煤层气 

分 类 号：TE132.2[石油与天然气工程—油气勘探]