致密砂岩储集层物性下限确定方法浅析

Research on the Determination Method of the Porosity and Permeability Cutoffs for Tight Sandstone Reservoir

随着致密油资源勘探开发工作的不断推进,致密砂岩储集层物性下限的研究也变得重要,对已发现油藏有效储集层物性下限的研究可以帮助预测勘探有利区。对前人工作和成果的研究显示,致密储集层物性下限的确定方法可以分为三类:一是正向研究法,通过对岩心样品的各类实验来求取储集层物性下限,包括毛细管压力法、模拟充注法、束缚水饱和度法、最小流动孔喉半径法和吸附水膜厚度法;二是反向研究法,通过实际的生产资料来求取储集层物性下限,包括试油资料统计法、孔隙度-渗透率交会图法、含油产状法、分布函数曲线法;三是综合研究法,将多种方法相结合来求取储集层物性下限。对比三类研究方法发现,正向研究法所求得的物性下限结果小于反向研究法取得的结果,但其实验过程较为复杂,而反向研究法取得的结果受限于现今的经济和技术条件,结果高于正向法确定的物性下限值,但其对生产指导意义更大,因此需要综合使用来确定致密储集层的物性下限。

With the advancement of tight oil resource explorat ion and development , the research of the porosi ty and permeabi l i ty cutoffs for tight sandstone reservoir becomes important, which can be used to predict favorable areas for exploration. Based on the study of others work, the determinat ion method for the porosi ty and permeabi l i ty cutoffs can be divided into three categories, （1） Posi tive method, to calculate the porosi ty and permeabi l i ty cutoffs through various experiments on cores, including capi l lary pressure analysis, the simulation of filling, the irreducible water saturation, minimum flow pore throat radius and the adsorpt ion of water film thickness; （2 ） Reverse method, to calculate porosi ty and permeabi l i ty cutoffs according to actual production data, including oil testing data statistics, cp - K crossplot, oil bearing condi tion of the tight sandstone, the distribution function curve method; （ 3 ） Comprehensive study method, to calculate the porosi ty and permeabi l i ty cutoffs wi th combined methods. Through the comparison of the three methods, it is found that the resul ts of posi tive study are less than that of reverse method, however,the process is compl icated relatively. And the reverse method is l imi ted by current economic and technical condi tions and the resul ts are larger than the posi tive method wi th greater signi ficance to guide production. Thus, integrated appl ication shal l be conducted to identi fy the porosi ty and permeabi l i ty cutof fs.