煤层气井低产水期产量预测模型  

Production prediction model of coalbed methane wells in low water production period

作　　者：刘金海 刘世界[1] 董建宏 杨宇光 张知斌 LIU Jinhai;LIU Shijie;DONG Jianhong;YANG Yuguang;ZHANG Zhibin(CNOOC Energy Technology&Services-Oil Production Services Co.,Tianjin 300452,China;China United Coalbed Methane Corporation Ltd.,Beijing 100011,China)

机构地区：[1]中海油能源发展股份有限公司采油服务分公司,天津300452 [2]中联煤层气有限责任公司,北京100011

出　　处：《油气井测试》2023年第3期1-5,共5页Well Testing

基　　金：国家科技重大专项“临兴—神府地区煤系地层煤层气、致密气、页岩气合采示范工程”(2016ZX05066)。

摘　　要：煤层气产量高低直接关系到区块或气井的开发价值,准确预测煤层气产量是选区、井位部署的关键环节。针对煤层气藏气井生产后期产水较少的情形,根据煤层气渗流连续性方程、煤层气解吸模型,推导得出煤层储层压力分布半解析解。结合压降叠加原理,推导建立了菱形井网中心井的产量预测模型。采用博文盆地Duckworth井组储层基础参数,预测气井产量,并与实际产量进行对比。结果表明,气井生产初期煤储层含水高,受该因素影响,该模型对煤层气生产初期产量预测效果差,预测相对误差达56%;但后期产水量较低时,实际产气量0.19×10^(4) m^(3)/d,预测产气量0.18×10^(4) m^(3)/d,预测相对误差仅5%,预测精度较高;该模型可在产水量较低的煤层气井产量预测中推广应用。The output of coalbed methane is directly related to the development value of blocks or gas wells.Accurate prediction of coalbed methane output is a key link in selecting areas and deploying well locations.According to the coalbed methane seepage continuity equation and coalbed methane desorption model,a semi analytical solution of coalbed reservoir pressure distribution is derived in view of the situation that the gas wells in coalbed methane reservoirs produce less water in the late production period.Based on the principle of pressure drop superposition,the production prediction model of the central well with rhombic well pattern is established.The basic reservoir parameters of Duckworth well group in Bowen Basin are used to predict the production of gas wells and compare it with the actual production.The results show that the coal reservoir has high water content at the initial stage of gas well production.Affected by this factor,the prediction effect of this model on the initial production of coalbed methane is poor,and the relative error of prediction is 56%;However,when the water yield is low in the later period,the actual gas yield is 1900 m^(3)/d,predicted gas production 1800 m^(3)/d,the relative error of prediction is only 5%,and the prediction accuracy is high;The model in this paper can be applied to the production prediction of coalbed methane wells with low water production.

关 键 词：煤层气井 封闭气藏 吸附 低产水期 储层压力 半解析解 产量预测 

分 类 号：TE377[石油与天然气工程—油气田开发工程]