柴达木盆地三大气田可采储量标定

COAL-BED METHANE DEVELOPMENT EVALUATION AT WUPU REGION

天然气可采储量在天然气开发中具有重要的作用。文章分别运用容积法和水驱法对柴达木盆地东部三大主力气田的采收率进行了预测 ,针对影响可采储量计算的几个重要参数进行系统分析 ,并对参数的取值作出具体要求 ,以提高可采储量计算的精度 ,更好地指导气田的开发。

Wupu region is one of the regions beneficial to coal-bed methane exploration and develpment,which were choosed out by CNPC through evaluating.This region is located in the eastern slope zone of E′erduosi Basin,where two sets of coal measure strata of the Shanxi Formation of the Lower Permian and the Taiyuan Formation of the Upper Carboniferous are mainly developed.The coal-bed methane showings were wide found in the wells within this region and the gas rush occurred in more than ten coal wells drilled.Well Wushi-1 is a coal-bed methane evaluation well drilled at this region.A production test work after fracturing in the well was being carried out for near six months,during which time a large number of testing data were being logged and a maximum coal-bed methane production of 1129 m 3 a day was reached.Through summarizing and analyzing the coal-bed geological conditions and coal-bed fluid properties of Wupu region and the performance characteristics of the production test in well Wushi-1,it is thought that the production test performance in well Wupu-1 may basically represent the typical performance characteristics of coal-bed methane wells and the major factors affecting the desorption by depressurizing in the coal measure strata at this region are the low coal-bed pressure,poor fluid deliverability and deficient fracturing scale.Meanwhile,through analyzing foreign examples it is considered that except the intrinsic factors as coal-bed thick,permeability and porosity etc.,the coal-bed damage and well-completion quality are the major factors affecting the drainge-production effectiveness of coal-bed methane wells;and that the repeated fracturing in coal-bed methane wells and the redrilling or lateral drilling in barefoot interval are the important measures for raising coal-bed methane well productivity.Finally,the meanes of improving coal-bed methane development effectiveness and some ideals of draining and producing the coal-bed methane at Wupu region are proposed in the paper.