杭锦旗地区低阻气层成因及测井评价方法

杭锦旗地区上古生界的勘探和生产资料证实该区发育较多低阻气层，但低阻成因目前尚不明确，给该区低阻气层的流体识别和测井评价，尤其是含水饱和度的计算带来较大困难。为此，利用分析化验资料和测井资料，分析并总结出该区低阻气层的成因为黏土矿物附加导电、微孔隙发育和地层水矿化度的影响；并基于该区低阻成因，总结了影响地层水导电性能的3类导电流体，即泥质(束缚水)、微孔隙导电流体(毛细管水)和大孔隙导电流体(自由水)，建立了改进的“双水模型”及相关参数估算方案来计算低阻气层的饱和度。实际应用结果表明，该方法在杭锦旗地区低阻气层的测井解释评价中效果良好，与测试结果符合较好；可为低阻气层测井评价提供一种技术方案。

Low-resistivity gas reservoir genesis and log evaluation method in Hangjinqi area

The exploration and production data in Hangjinqi area confirmed that there are many low-resistivity gas reservoirs.However,the genesis of low-resistivity is not clear,this situation affects the fluid identification and log evaluation,especially the calculation of water saturation.Thus,by using the laboratory measurements and well logs,genesis of the low-resistivity is analyzed and summarized as three reasons.They are additional conductivity of clay mineral,micro-pore development and the influence of formation water salinity.By using the “core scale logging” method,the conventional log calculation models of reserve parameters are established.Based on the genesis of low-resistivity gas reservoir,three conductive fluids,which can affect the electrical conductivity of formation water,are summarized such as shale (the bound water),micro-pore conductive fluid (the capillary water) and macro-pore conductive fluid (the free water).Therefore,the improved “dual-water saturation model” and the estimation solutions of the corresponding parameters are proposed to calculate the saturation in low-resistivity gas reservoir.Field examples confirmed that,by using the method,the reliable evaluation results,which matched well with the test results,can be obtained in the low-resistivity gas reservoir in Hangjinqi area.It can provide a technology solutions for log evaluation in low-resistivity gas reservoir.