气测录井全量正演计算方法判别低孔低渗储层含气性

摘要

低孔低渗储层流体性质识别一直是东海盆地西湖凹陷近年勘探中的一大难题.分析认为,此类储层渗透率低,钻进过程中孔隙内的气体不易被钻井液滤液驱替,地下破碎岩石中的气量与Flair录井仪实测气测全量值有很好的一致性.基于此,本文提出通过测井总孔隙度、含气饱和度,结合地层压力和钻井参数进行气测录井全量正演计算,并与实测气测全量值进行对比,从而实现快速准确判别低孔低渗储层流体性质和直接评价低孔低渗储层含气性的目标.东海盆地西湖凹陷应用表明,本文提出的气测录井全量正演计算方法合理可行且具有通用性,可进一步推广应用.%Reservoir fluid identification is a big challenge in the exploration of low porosity and low permeability formation in Xihu sag, East China Sea basin.Analyses show that the gas volume in the drilling cutting has a good correlation with that of measured from Flair mud logging equipment because the gas bearing in the low porosity and permeability formation is difficult to be displaced by drilling fluid.Base on these analyses, a forward calculation method of gas logging data is proposed based on integrating the total porosity, saturation, formation pressure and drilling parameters, and the calculation total gas volume is compared with actual measured total gas volume from Flair data.The method can evaluate fluid property and gas saturation in low porosity and low permeability reservoir rapidly and accurately.The application in Xihu sag of the East China Sea shows that the total gas forward calculation method is feasible and universal, and can be further applied.