【摘要】 基于扶余油层和杨大城子油层典型河道砂岩岩心样品，利用CT扫描物理实验和数字岩心重建技术，开展低渗透砂岩微观孔隙结构表征及渗流机理分析。通过矿物组分定量分析和扫描电镜拼图成像技术，识别出岩心矿物种类及其含量，划分出粒间孔、粒内孔和填隙物内孔共3种孔隙类型。针对总孔隙空间进行等效半径分布曲线计算，呈现明显的双峰结构，峰值主要集中在约50μm和约1μm。利用重构的数字岩心模型模拟油水两相渗流，模拟结果显示，扶余油层油水共渗区较宽，残余油饱和度为30%～45%;杨大城子油层油水共渗区较窄，残余油饱和度为40%～55%。在毛管力和亲水性的作用下，水相优先进入小孔道，小孔道先于大孔道形成水锁，相较于扶余油层，杨大城子油层的喉道半径小，数量多，更易形成水锁，残余油饱和度较高。更多还原

【Abstract】 Based on the core samples of the typical channel sandstone from Fuyu and Yangdachengzi Reservoir, CT scanning physical experiments and digital core reconstruction technology were used to characterize the microscopic pore structure and analyze the seepage mechanism of low-permeability sandstone. By means of quantitative analysis of mineral composition and scanning electron microscopy, the types and contents of core minerals were identified, and three pore types were classified: intergranular pores, intragranular pores and interstitial pores. The equivalent radius distribution curve of the total pore space was calculated, showing an obvious bimodal structure, and the peak values were mainly approximately 50 μm and 1 μm. The reconstructed digital core model was used to simulate oil-water two-phase seepage. The simulation results showed that the oil-water coseepage zone of Fuyu Reservoir was wide and the residual oil saturation was approximately 30%-45% in the process of oilfield development. The residual oil saturation of Yangdachengzi Reservoir was approximately 40%-55%. Under the action of capillary force and hydrophilicity, the water phase preferably entered the small pore channel, and the small pore channel formed the water lock before the large pore channel. Compared with the Fuyu Reservoir, the throat radius of Yangdachengzi Reservoir was smaller, and the number was greater, which made it easier to form a water lock, and the residual oil saturation was higher.更多还原