数理统计法确定物性下限的方法优选  

Method optimization of determining the lower limit of physical properties by mathematical statistics

作　　者：李谋杰[1] 张豆娟 陈冬[3] 傅爱兵 袁瑞[1] LI Moujie;ZHANG Doujuan;CHEN Dong;FU Aibing;Yuan Rui(College of Geophysics and Petroleum Resources,Yangtze University,Wuhan 430100,Hubei;Research Institute of Exploration and Development,Shengli Oilfield Company,SINOPEC,Dongying 257015,Shandong;Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 100083)

机构地区：[1]长江大学地球物理与石油资源学院,湖北武汉430100 [2]中石化胜利油田分公司勘探开发研究院,山东东营257015 [3]中石化石油勘探开发研究院,北京100083

出　　处：《长江大学学报（自然科学版）》2024年第6期45-50,共6页Journal of Yangtze University(Natural Science Edition)

基　　金：国家自然科学基金项目“基于偏正态混合模型和支持向量机的粒度分布数据挖掘”(42202113)。

摘　　要：针对数理统计法确定物性下限的一些问题进行了分析。在有效样本和非有效样本个数大致相当的情况下,依据不同含油产状岩心物性分析数据分别采用自然分布百分比法、块数折合百分比法、正逆累积法确定物性下限,结果基本一致,但受物性分类区间影响,精度不高。考虑样本数据体差异过大的影响,引入有效样本的折合系数或者样本归一化处理的百分比正逆累积法,在一定程度上克服了自然分布统计法中因有效样本占绝对优势而使统计出的下限偏低的问题,但仍然受物性分类区间的影响,精度不够高。为了更好地压制有效样本与非有效样本的统计数据体差异较大问题,提高精度,提出利用百分比正逆累积散点曲线法进行逐点绘图。经过A油田某目的层段岩心样本数据对比分析,利用百分比正逆累积散点曲线图确定孔隙度下限为7.4%,与实测油层最低孔隙度值7.4%一致;对B油田某目的层段岩心样本数据对比分析,百分比正逆累积散点曲线图确定渗透率下限为400 mD,与实测油层最低渗透率410 mD基本一致。两个实例均显示百分比正逆累积散点曲线法更可靠,确定的物性下限精度更高。Some problems of determining the lower limit of physical properties by mathematical statistics are analyzed.Under the condition that the number of valid samples and non-valid samples is roughly equal,the natural distribution percentage method,block number conversion percentage method and forward and inverse accumulation method are used to determine the lower limit of physical properties according to the analysis data of different oil-bearing core properties,their results were roughly consistent,but the accuracy is not high due to the influence of physical properties classification interval.Considering the influence of large differences in sample data bodies,the conversion coefficient of valid samples or the percentage forward and inverse accumulation method of sample normalization is introduced to overcome the problem of low lower limit of statistics due to the absolute advantage of valid samples in natural distribution statistics,but it is still affected by the physical property classification interval,and the accuracy is not high enough.In order to suppress the large difference of statistical data between valid and invalid samples and improve the accuracy,a point-by-point plot is proposed by using the percentage forward and inverse cumulative scatter graph method.By comparing and analyzing the core analysis data in target layer of A oilfield,the lower limit of porosity is determined to be 7.4%by using the percentage forward and inverse cumulative scatter graph method,which is consistent with the measured minimum porosity value of 7.4%.By comparing and analyzing the core analysis data in target layer of B oilfield,the lower limit of permeability determined by the percentage forward and inverse cumulative scatter graph method is 400 mD,which is roughly consistent with the measured minimum permeability value of 410 mD.Both examples show that the method of percentage forward and inverse cumulative scatter graph method is more reliable,the lower limit of physical properties is more accurate.

关 键 词：数理统计法 百分比正逆累积散点曲线图法 物性下限 

分 类 号：TE122.23[石油与天然气工程—油气勘探] P618.130.21[天文地球—矿床学]