环池油田侏罗系延8油层组储层特征

Reservoir feature of Jurassic 8th member of Yan'an for- mation in Huanchi oilfield

环池油田构造上处于鄂尔多斯盆地西缘冲断带中段,储层为侏罗系延安组河道砂岩,岩石类型以岩屑石英砂岩为主,孔隙类型主要为原生孔隙和次生孔隙,孔隙度12％～16％,平均为12．6％,渗透率(0．5～50．0)×10-3μm2,平均11．19×10-3μm2。孔隙半径5．00-34．91μm,平均32．30μm;平均喉道半径为1．19μm。按性质将储层划分为四种类型,Ⅰ、Ⅱ类为较好储层,是油田主要产层,Ⅲ类为差储层,Ⅳ类为非渗透层;综合评价为低孔低渗中孔隙细喉型储层。

Situated in the middle part of the west margin of Or-dos basin, the reservoirs in Huanchi oil field belong to Jurassic Yan'an formation channel sandstone, the rock type is mainly lithic quartz sandstone, the porosity type is mainly primary and secondary, with 12% -16% porosity, the average is 12.6%, the permeability(0.5~50)×103μm2 ,the average is 11. 19×10-3μm2, the pore radius is 5-34. 91μm, the average is 32. 3μm and the average throat radius is 1. 19μm. The reservoirs in the area can be divided into four types according to the above characteristics, among whichⅠandⅡare of good reservoirs,Ⅲis of poor reservoir, andⅣis of impermeable reservoir. It is concluded from the comprehensive evaluation that the reservoir in the area is of low - porosity and low - permeability, medium-porosity and fine-throat.