储集层非均质性分析的计算机方法:以西弗吉尼亚州下密西西比系油田为例

COMPUTER METHODS FOR ANALYSIS OF RESERVOIR HETEROGENEITY: EXAMPLE FROM A LOWER MISSISSIPPIAN OIL FIELD IN WEST VIRGINIA

摘要:

本文使用几种计算法和统计法研究美国西弗吉尼亚洲中部格兰尼克里克油田大Injun砂岩储集层的结构及其与采油量的关系。计算机程序根据已出版的资料编写,以适合(1)计算渗透率对孔隙度的回归;(2)标绘三维孔隙度;(3)确定和标绘根据地球物理测井记录推断的相;(4)估算原始储量、累积产量和采油率。因为回归分析显示出测井记录和岩心孔隙度及岩心渗透率间微弱但重要的相关,所以,孔隙度可用于地层渗透率中以构成储集层的模式。也使用定量地层对比和多维定算法来估算在缺乏可用数据的情况下构造的影响。于井间使用克里格法内插绘制的剖面,突出了孔隙度较高的地带。使用地球物理测井资料和岩心描述,用聚类分析确定导电相。原始储量的估算结果与累计产量数据相结合,得出采油率的估算值。这些采油量变量图通常呈现在岩相图上观察到的相同的南北走向。

Abstract:

Several computational and statistical methods were used in the study of reservoir architec-ture and its relationship to oil production from the Mississippian Big Injun sandstone in Granny Creek field,central West Virginia(USA). Computer programs were written or adapted from published sources to:1)calculate the regression of permeability on porosity;2)map porosity in three dimensions;3)define and map facies inferred from geophysical logs;and 4)estimate origi-nal oil in place,cumulative production,and recovery efficiency. Because regression analysis showed a weak but significant relationship between log and core porosity,and core permeabili-ty,porosity could be used in place of permeability to construct models of the reservoir. Quantita-tive stratigraphic correlation and multidimensional scaling were used to eliminate the effects of structure in the absence of a usable datum. Kriging was used for interpolation between wells, and the results were drawn as cross sections to highlight zones of relatively high porosity. Geo-physical log data and core descriptions were used to define electrofacies by cluster analysis. Esti-mates of original oil in place were combined with cumulative production data to yield estimates of recovery efficiency. Maps of these oil production variables generally showed the same north-south trend observed on lithofacies maps.