基于气测录井资料的灰色关联法识别储集层流体性质

Identification of reservoir fluid properties by grey correlation method based on gas logging data

塔木察格盆地南贝尔凹陷构造条件复杂,孔隙类型多样,非均质性强,目标区内南屯组储集层流体性质识别难度较大,传统测井、录井图板解释结果均不理想。对储集层流体性质的准确判别,已成为南贝尔凹陷勘探、开发亟待解决的重点问题。为了探讨储集层流体性质识别的有效方法,将加权灰色关联分析应用到流体性质解释工作中。在试油证实的南贝尔凹陷南屯组储集层中,分别选出不同流体性质所对应的7项气测参数,统计高频气测参数值的平均值构建标准序列,使用待识别的储集层对应的气测参数构建比较序列,作加权灰色关联分析,得到待识别储集层与标准流体类型的关联度,根据最大隶属度原则实现待识别储集层流体性质的正确归属。其中,各气测参数权重的求取是建立在对应分析和熵函数两者严格的数学基础之上,克服了其他方法存在的不足。对南贝尔凹陷的28个待识别储集层含油气类型的实例判别分析表明,基于气测录井的加权灰色关联识别储集层流体性质模式的方法计算过程简单,正判率约为82.14%,为该地区流体识别提供了可供参考的依据。

The structural condition in Nanbeier sag of Tamtsag Basin is complicated with various types of pores and strong heterogeneity,the identification of reservoir fluid properties of Nantun formation in target area is difficult.The chart interpretation results of conventional well logging and mud logging are not ideal.The accurate discrimination of reservoir fluid properties has become a key problem to be solved urgently in the exploration and development in Nanbeier sag.In order to study effective methods to identify the reservoir fluid properties,the weighted grey correlation analysis was applied to the fluid property interpretation.In the reservoirs proved by oil test in Nantun formation of Nanbeier sag,seven parameters corresponding to different fluid properties were selected respectively,and the average value of statistical highfrequency gas logging parameters can construct the standard sequence.A comparative sequence is constructed by using gas logging parameters corresponding the reservoir to be identified,making weighted grey correlation analysis can obtain the degree of association between the reservoir to be identified and the type of standard fluid.The correct attribution of the fluid property of the reservoir to be identified is achieved according to the principle of maximum subordinate degree.In this paper,the weighting is based on the rigorous mathematical foundations of the corresponding analysis and entropy function,which can overcome the shortcomings of other methods.The discriminant analysis of oil and gas types of 28 reservoirs to be identified in Nanbeier sag indicated that the calculation process for the method of the weighted grey correlation identification of the reservoir fluid property based on gas logging is simple and the positive discriminant rate was about 82.14%.It provides a reference for fluid identification in this area.