定边X区长8储层孔隙特征及其对油水流动的影响  

Pore characteristics and their influences on the water-oil flow for Reservoir Chang-8 in Dingbian Block X

作　　者：李晓骁 任晓娟[1] 田进 马焕焕 LI Xiaoxiao;REN Xiaojuan;TIAN Jin;MA Huanhuan(College of Petroleum Engineering,Xi’an Shiyou University,Xi’an 710065,China)

机构地区：[1]西安石油大学石油工程学院,陕西西安710065

出　　处：《大庆石油地质与开发》2020年第1期41-49,共9页Petroleum Geology & Oilfield Development in Daqing

基　　金：国家“十三五”科技重大专项“鄂尔多斯盆地大型低渗透岩性地层油气藏开发示范工程”(2016ZX05050006)。

摘　　要：致密砂岩储层微观孔隙结构及其孔隙空间中流体的渗流特征是影响油气田开发的关键因素。以定边X地区长8油藏为例,基于铸体薄片、扫描电镜、高压压汞等技术手段对孔喉结构特征进行分类和评价,通过油水相渗和渗吸实验,结合核磁共振技术,探讨了不同孔隙结构特征对渗流特征及油水流动下限的影响。结果表明:研究区孔隙结构复杂,非均质性强,分为中大孔型和溶孔缝型两类主要孔隙组合。中大孔型物性相对较好,中大孔占比高,水驱和渗吸驱油效率高,流体流动能力相对较好;溶孔缝型物性差,微纳米孔喉发育,水驱和渗吸效率低,残余油饱和度高。中大孔型和溶孔缝型的油水流动下限分别是0.08μm和0.075μm,表面活性剂可以明显改善流动能力,并降低流动下限至0.05μm,但是仍有大量残余油滞留在亚微米孔喉(<1μm),中等孔径的孔喉(1~25μm)对自发渗吸起主要作用,中大孔径的孔喉是流体渗流的主要通道。Microscopic pore structures of the tight sandstone reservoir and their fluid flow characteristics in the pore space are the key factors affecting the oil and gas exploitation. Taking Oil Reservoir Chang-8 in Dingbian Block X as an example, based on the thin section observation, scanning electron microscope, high-pressure mercury intrusion and the other technical methods, the features of the pore throat structure were classified and evaluated. By means of the oil-water relative permeability and imbibition experiments combined with nuclear magnetic resonance technique, the influences of different pore structure characteristics on the flow property and lower limit of the oil-water flow were discussed. The results show that the properties of the pore structure in the study area are rather complex and moreover the heterogeneity is strong, two kinds of the main pore combination are divided: Middle-macro pore and dissolved pore-fracture. The former is characterized by relatively better physical properties, high-proportion middle and macro pores, high-efficiency water-flooded and imbibition, and relatively better flow ability;the latter’s physical properties are rather poorer, characterized by well-developed micro-nano pore throats, the water-flooded and imbibition efficiencies are rather lower, while the residual oil saturation is rather higher. The lower limits of the oil and water flow for these two kinds of the pore are 0.08 μm and 0.075 μm respectively, the surfactant can obviously improve the flow capacity and the lower limits can be decreased to 0.05 μm. However, a large number of the residual oil is still remained in the submicro pore throat(<1 μm), the middle pore throat(1-25 μm) plays the major role in the spontaneous imbibition, and the macro pore throat is the main channel for the fluid flow.

关 键 词：致密砂岩储层 孔隙结构 油水渗流 渗吸 核磁共振 表面活性剂 流动下限 

分 类 号：TE311[石油与天然气工程—油气田开发工程]