齐家-龙西地区扶余致密油储层特征研究

Study on Characteristics of Fuyu Tight Oil Reservoir in Qijia-Longxi Area

近年来,齐家-龙西地区扶余油层提交了大量的探明储量,由于扶余油层沉积环境为三角洲平原和前缘亚相,但其主要为渗透率1.5mD左右的致密油层,通过对储层岩石的矿物成分、孔隙和喉道的几何形态、大小、分布及其相互之间的连通关系进行评价和分析,结果表明其储层岩石颗粒细小、排列紧密,粘土成分含量高等造成扶杨油层孔隙以缩小粒间孔为主,面孔率低,连通性差,常规水驱开发难度大。喉道半径小是造成储层渗流能力低的主要原因,渗透率小于1mD时,喉道以半径小于1μm微喉道、微细喉道为主;渗透率在1~2mD时,喉道以微细喉道和细喉道为主;随着渗透率的增加,其可动流体百分数也随之增大,成对数关系,1.0mD的储层其可动流体为41.4%,说明对于致密油层而言,注水开发难度大,可动流体含量低,稳产难度大。本文对扶余油层孔隙结构及渗流特征的研究,可谓为扶余油层不同尺度孔隙介质储层开发方式的优选提供技术支撑。

In recent years,a large amount of proven reserves have been submitted in the Fuyu oil layer in the Qijia-Longxi area.Since the sedimentary environment of the Fuyu oil layer is the delta plain and the front margin subfacies,it is mainly a tight oil layer with a permeability of about 1.5 mD.The mineral composition,pores and throat geometry,size and distribution of the reservoir rocks and their interconnections are evaluated and analyzed.The results show that the reservoir rocks are fine,closely arranged,and the clay content is high.The porosity of the oil layer is mainly to reduce the intergranular pores,the face rate is low,the connectivity is poor,and the conventional water flooding development is difficult.The small throat radius is the main reason for the low seepage capacity of the reservoir.When the permeability is less than 1 mD,the throat is mainly micro-throat and micro-throat with a radius of less than 1μm;when the permeability is 1~2 mD,the throat is micro-throat The channel and the fine throat are dominant;as the permeability increases,the percentage of the movable fluid also increases,in logarithm relationship,the 1.0 mD reservoir has a movable fluid of 41.4%,indicating that for dense reservoirs The water injection development is difficult,the movable fluid content is low,and the stable production is difficult.In this paper,the study on the pore structure and seepage characteristics of the Fuyu oil layer can be said to provide technical support for the optimization of the development methods of the pore medium reservoirs in different scales of the Fuyu oil layer.