G区长4+5致密砂岩储层非均质特征研究

Heterogeneity Characteristics of the Chang 4+5 Tight Sandstone Reservoirs in Area G

陕北斜坡东部致密油藏含油层位大多在延长组,通过岩心及测井资料等对G区长4+5储层的非均质性进行分析研究。不同渗透率韵律变化是不同沉积作用下各沉积相的直观体现,同时也反映了储集砂体的非均质性:层内非均质性主要体现为沉积韵律性、沉积构造、砂泥组合形式等方面的差别,层间非均质性通常用砂层钻遇率、单砂层厚度、砂地比等参数来描述,平面非均质性主要表现在孔隙度和渗透率的平面特征上。研究结果表明,从层内非均质性来看,G区长4+5层内非均质性相对较弱,平均夹层数长4+5-1~2最大,其次为长4+5_1~1、长4+5_2~2,长4+5_2~1最小;层间非均质性分析认为G区储层有相对较强的非均质性;平面非均质性反映了不同层段的孔渗变化较为明显,也说明了G区致密砂岩储层非均质性普遍较大,区内物性相对较差,油层相对不发育,平面上主要发育于分流河道砂体中心部位。

Oil-bearing formations in th formation mostly.The heterogeneity of e tight oil reservoirs in eastern Shanbei slope are developed in Yanchang the Chang4＋5 reservoirs in area G was studied by core and logging data.The rhythm variation of different permeability reflects the sedimentary facies under different sedimenta- tions.In the meantime,it reflects the heterogeneity of the sandbody：intraformational heterogeneity is the differ- ence on sedimentary rhythm,sedimentary structure, erogeneity is generally described by sand drilling and sand-mud combination form mainly,and interlayer het- rate ,single sand thickness and ratio of sand thickness and formation thickness,and plane heterogeneity is the plane characteristics of porosity and permeability.Research results present that the intraformational heterogeneity of Chang4＋5 reservoirs in area G is relatively weak,and the average interlayer number is in the descending order in Chang4 ＋5 1^2, Chang4 ＋5 1^1 and Chang4 ＋5 2^2, and Chang4 ＋5 2^1;the reservoirs in area G has relatively strong heterogenelty;the obvious variation of porosity and permeability in various layers and intervals the tight sandstone reservoirs generally.In the area G,the physical property is is not developed relatively.The reservoirs were developed at central position mainly on the plane. plane heterogeneity reflects the and the strong heterogeneity of relatively poor,and oil reservoir of distributary channel sandbody