准噶尔盆地玛湖凹陷下三叠统百口泉组低渗砾岩储集层岩性复杂,黏土矿物复杂,非均质性强,现有测井方法均难以精确表征砾岩储集层的有效孔隙度.为此,在考虑了黏土矿物含量是储集层物性控制因素的基础上,利用中子测井孔隙度和核磁共振测井孔隙度之差与岩心分析黏土矿物含量建立黏土矿物含量表征模型;再用岩心分析黏土矿物束缚水孔隙度与黏土矿物含量,建立了黏土矿物束缚水孔隙度表征模型,据此利用核磁共振测井孔隙度减去黏土矿物束缚水孔隙度求得有效孔隙度.将该方法应用到研究区19口探井的有效孔隙度计算中,相对误差仅为6.8％,表明该方法应用效果较好,为今后利用核磁共振测井资料评价有效孔隙度提供了新的技术手段.%The low-permeability conglomerate reservoir in the Lower Triassic Baikouquan formation of Mahu sag,Junggar basin is characterized by complex reservoir lithology,complicated clay minerals and serious heterogeneity,so it is difficult to accurately characterize the effective porosity of the conglomerate reservoir with current logging methods.Considering that the clay mineral content is the controlling factor of reservoir physical properties,the paper uses the difference between neutron logging porosity and NMR logging porosity and clay mineral content obtained from core analysis to establish a clay mineral content characterization model;then uses clay bound water porosity and clay mineral content obtained from core analysis to establish a clay bound water porosity characterization model,based on which the effective porosity can be obtained by NMR porosity minus clay bound water porosity.The actual application of the method in 19 exploration wells in the study area shows that the relative error of effective porosity is only 6.8％,indicating that good effect has been gained by using the method,which could provide a new technological means for effective porosity evaluation with NMR logging data.
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