等速型砂泥岩区自然伽马反演可信度探讨:以YQ2井三维地震区为例  

A Reliability of GR Inversion Technique Performanced in Iso-velocity Sandstone and Shale Reservior:An Example of Well YQ2 in 3D Survery Area

作　　者：武岳[1,2] 蒲仁海[1] 郭向东[2] 刘宝平 刘朋波[1] 

机构地区：[1]西北大学大陆动力学国家重点实验室,西安710069 [2]西北大学地质学系,西安710069 [3]延长石油股份有限公司勘探部,陕西延安716000

出　　处：《地质科技情报》2011年第5期132-138,共7页Geological Science and Technology Information

基　　金：延油气勘发项目(2008字第115号)

摘　　要：工区目的层的岩性主要为低速煤层、高速灰岩和等速砂泥岩,地震资料中波阻抗和强振幅主要反映了低速煤层和高速灰岩,由于砂泥岩为等速,所以利用速度反演和波阻抗不能有效解决该类型砂岩储层的识别问题。通过孔隙度反演和有争议的自然伽马反演探讨了砂岩厚度和有利储层预测的可信度。3种反演的结果对比表明,在砂泥岩等速和存在煤层、灰岩等异常速度岩性的干扰下,波阻抗反演的砂岩厚度与实钻砂岩厚度吻合率最低,自然伽马反演吻合率最高,孔隙度反演吻合率居中。本次研究还将自然伽马反演的砂岩厚度图与人工手绘以及计算机克里金内插法所得的砂岩厚度图进行了对比,自然伽马反演与钻井的吻合率要高于人工手绘和克里金内插法结果,并且自然伽马反演砂岩厚度图的砂体展布形态和物源方向明显且唯一。The principal rocks in the study area are mainly composed of low-velocity coal layer,high-velocity carbonates and iso-velocity sandstone and shale layers.Seismic acoustic impedance and high amplitude are caused by low-velocity coal and high-velocity carbonate layers.Since sandstone shares the same feature as shale in velocity in this area,it is not effective to utilize acoustic impedance and velocity inversion techniques to identify the sandstone reservoir.This study covers the reliability of predicting sandstone thickness and favorable reservoir based on porosity inversion and Gamma-Ray log inversion.In comparison with three inversion methods above,the results show that Gamma-Ray log inversion matches the field data well and porosity inversion moderately.In contrast,the worst performance is found by acoustic impedance inversion and drilling sandstone thickness.This research also compares the sandstone contour maps drawing by Gamma-Ray log inversion,manually depicting and Kriging interpolation methods,respectively.Similarly,the Gamma-Ray log inversion method presents a better answer than the other two.Also,iso-thickness of sandstone derived from Gamma-Ray log inversion technique exhibits an identical distributed pattern with source direction.

关 键 词：等速砂泥岩 自然伽马反演 波阻抗反演 孔隙度反演 储层预测 

分 类 号：P631.4[天文地球—地质矿产勘探]