MOEKey Lab of Marine Reservoir Evolution and Qil and Gas Enrichment Mechanism,China University ofGeosciences ( Beijing) MOLR Key Lab of Shale Gas Resources Survey and Strategic Evaluation,China University of Geosciences ( Beijing ) China United Coalbed Methane Corporation Limitec

为了研究排采制度对柿庄南区块煤层气井产气量的影响,通过对柿庄南区块4口高产井排采曲线进行对比分析,探索总结了高产井排采曲线的共同特征,优选出了适合柿庄南区块的排采制度。结果表明:高产井的排采曲线呈现阶梯状变化规律特征。产气后井底流压的变化分为4个阶段,即:缓慢下降阶段、逐级降压阶段、迅速下降阶段和稳定阶段;缓慢降压阶段为排采初期排水降压阶段到不稳定产气阶段的过渡阶段;逐级降压阶段储层压力逐渐下降,压降漏斗稳定向远端延伸;在迅速下降阶段,出现了井间干扰使得压降漏斗相互叠加并向深处扩展,产气量陡增;稳定阶段,是井底流压下降到一个较低水平并保持长期稳定,气体稳定解吸,产气量稳定在一个较高水平。迅速下降阶段之前稳定套压,之后缓慢释放套压,有利于储层防护。井底流压见气前平缓下降,见气后阶梯状变化的排采制度有利于柿庄南区块排采井的高产。

in order to study the drainage system aff cted to the gas production of the coalbed mnethane wells in the South Block of Shizhuang.a compaiscn anaysis was conducted on the drainage curves of four high producton wells in the south bfock of Shizhuang. The paer d scovered and summaized th common fetues of he gas drainage curves from the high producton wells and optimized the drainage system suitable to the south block of Shihuang .The resuis showed that the drainage curves of the igh producion wells had ladderstyle vaiation law and features. After the wels in the gas producton.the vaiation of th botiom fowing pressure had four stages and they were a slow pressure drap stage,steady pressure reduction stagerapid drop stage and stable stage.The s ow pressure drop stage was atrnstionalstae fom the water pumping and prssure drop stage to the instablegas producton stage in the gas drainageintal perod. The reservoir prssure at the steadly pressure reduction stage would be steadili reduced and the pressure drop hopper would be stably extended to a far end. /n th pressure rapid drop stage.the inerierences occurred between the wells would make the pressure drop hoppers overlapping and expanded to the deep section and thegasproduction would be sharply increased.The stable stage would mean the botom f1owing pressure drop to a low lvel and keeing a long erod stabl ,the gas would be stably desorbed and the gas productiowould be stable at a high level. Before the rapid pressure drop stage.thecasing pressure should be kept in stable,th n thecasing pressure coult be slovwl released and would be favorable to protect the reservoir.The boton fowing pressure should be seadil reduced before the gas occured in the well and afer th gas occured inthe well the drainage system with a ladder-style variation would be favorable to the high production of the gas drainage wells in the study area.

国家科技重大专项资助项目(2011ZX05060；2011ZX05034-003)；