致密砂岩储层微观水驱油实验及剩余油分布特征——以鄂尔多斯盆地吴起油田L1区长7储层为例  

EXPERIMENTAL STUDY ON MICROSCOPIC WATER DISPLACEMENT IN TIGHT SAND⁃STONE RESERVOIRS AND CHARACTERISTICS OF REMAINING OIL DISTRIBUTION-A CASE STUDY OF CHANG 7 RESERVOIR OF L1 AREA IN WUQI OILFIELD,ORDOS BASIN

作　　者：杨振亚[1] 罗辉[1] 周宾宾 刁广智 李小龙[1] YANG Zhen-ya;LUO Hui;ZHOU Bin-bin(No.5 Oil Production Plant of PetroChina Changqing Oilfield Company,Xi'an 710018,Shanxi,China)

机构地区：[1]中国石油长庆油田分公司第五采油厂,陕西西安710018

出　　处：《新疆石油天然气》2020年第4期59-65,I0004,共8页Xinjiang Oil & Gas

基　　金：国家科技重大专项(2016ZX05050--002)资助。

摘　　要：为明确致密油藏水驱过程中油水两相渗流特征及微观剩余油分布规律,以鄂尔多斯盆地吴起油田长7储层为例,在高压压汞、扫描电镜和铸体薄片分析的基础上,通过开展高温高压微观岩心切片水驱油实验,研究了水驱过程中的微观驱替特征,对比评价了不同孔隙结构岩心的驱油效率,揭示了水驱后微观剩余油分布规律。实验结果表明,研究区长7储层不同物性岩石样品具有不同的微观孔隙结构特征,决定了其具有不同的启动压力及多样的水驱油驱替类型,进而决定了不同样品的驱油效率差异性较大。其中均匀驱替型的驱油效率最高,网状驱替和树枝状驱替次之、蛇状驱替最差。微观孔喉结构的非均质性决定了水驱过程中油水运移特征及微观剩余油分布规律。当不同类型孔隙空间作为主要的渗流通道时,微观剩余油的分布存在较大差异性,注入水总是优先驱替大孔和裂缝中的油相,并形成优势通道,剩余油主要分布在优势通道以外小孔微吼处。取得的成果为该区提高水驱采收率提供了指导和借鉴。Experimental study of microscopic water flooding can clarify the characteristics of seepage and the distribution of microscopic residual oil in the process of oil and water displacement.Taking the Chang 7 reservoir in the H area of the Jiyuan oilfield of Ordos Basin as an example,this paper studies the displacement characteristics of the water flooding process through the micro water flooding experiment of several groups of samples and compares the displacement efficiency of differ⁃ent physical samples.On this foundation above,the distribution law of the micro residual oil is summarized.The study shows that different physical properties of rock samples in the long 7 reservoir of H area have different microscopic pore structure characteristics,which determine the different starting pressure and various flooding displacement types,and then determine the difference of oil displacement efficiency of different samples.Among them,the higher displacement efficiency of water flooding is,the better flooding effect is.The heterogeneity of microscopic pore throat characteristics determines the distribu⁃tion of residual oil in the process of water flooding.When the pore space is the main flow channel,the distribution of micro re⁃sidual oil is very different.The injection water always gives priority to the relatively larger holes and the oil in the seams to form the dominant channel,which makes the remaining oil distributed in the small pore and micropore outside the dominant channel.

关 键 词：鄂尔多斯盆地 致密砂岩 微观 水驱油 微观剩余油 

分 类 号：TE327[石油与天然气工程—油气田开发工程]