用多元逐步回归方法评价储层孔隙度的控制因素

储层岩石孔隙度受多种因素控制 ,对其进行定量分析是储层地质学中的难点之一。采用多元逐步回归分析方法对鄂尔多斯盆地 W地区某油层组的样品进行拟合 ,取不同的门槛值 ,得到不同的拟合方程。根据这些方程分析了其地质意义 ,并得出结论 :(1 )面孔率与各种地质因素之间存在很好的相关关系 ,复相关系数 R=0 .97885 (门槛值为 2 .8～ 0 .3 3时 ) ;(2 )通过实际应用的检验 ,说明在已知参数的情况下 ,逐步回归方程可以预测储层质量并评价其控制因素 ;(3 )在 W地区某油层组中 ,浊沸石溶蚀率和长石溶蚀率是对面孔率贡献最大的参数 ;(4 )压实作用 ,浊沸石、长石和石英的胶结作用是较重要的影响因素 ,碳酸盐胶结物和岩屑溶蚀率 ,埋藏深度 ,杂基含量 ,碎屑的分选和粒度等对面孔率的控制作用相对较弱 ;(5 )碳酸盐、浊沸石、长英质胶结作用和杂基含量不利于储层孔隙发育 ,长石溶蚀率、浊沸石溶蚀率、岩屑溶蚀率、粒间体积、颗粒直径和分选程度都有利于孔隙的发育。

ESTIMATION OF CONTROLLING FACTORS OF RESERVOIR POROSITY BY USING MULTIPLE STEPWISE REGRESSION ANALYSIS

The porosity of the clastic reservoir rocks is controlled by many different factors. In practice, because there are many variable factors, quantitative analysis is difficult to make in a general way. Based on the multiple stepwise regression analysis, this paper fit all of the data of Yanchang formation in some part of Ordos Basin. By selecting different threshold values, the authors get different regression equations. Through analyzing their geological significance of these equations, the authors get the following conclusions . (1) There exists good correlative connection between the porosity and the geological factors (correlation coefficient is 0.87563). (2) After the practical test, the authors know that the regression equation can be used to predict the quality of the clastic reservoirs, especially to estimate the control factors of the reservoirs after knowning the parameters. (3) The ratios of the corrosion of laumonite and feldspar are the two most important parameters to porosity. (4) The compaction and cementation of laumonite, feldspar and quartz are relatively important factors. Other factors such as carbonate cement, depth, the content of the matrix, sorting, grain size are relatively unimportant. (5) The cementation of carbonate, laumonite, feldspar, and quartz, and the matrix are unfavorable to reservoir quality, whereas the corrosion of feldspar, rock fragment and laumonite,the intergranular porosity, the diameter and sorting of grains are favorable to reservoir quality.