摘要
为深入剖析超低渗储层微观孔隙结构非均质性对渗流机理的影响程度,选取鄂尔多斯盆地西峰油田长8储层有代表性的样品进行了真实砂岩微观模型水驱油和CT扫描水驱油驱替实验。通过真实砂岩微观模型水驱油实验发现,对于没有微裂缝存在的岩样,水驱油效果往往与渗透率成正比关系,而微裂缝的存在使得微观孔隙结构非均质性显得更加突出,渗流机理将完全改变,从而水驱油效果也表现出较大的差异。CT扫描水驱油驱替实验结果也表明,微裂缝的存在明显增加了孔喉微观非均质程度,使得水驱效果变差。而环压对具有双重孔隙介质储层的注水效果会产生较大影响。可见对于超低渗储层,微观孔隙结构非均质性是造成注入水波及效率不高、水驱油效果差的主要原因。
Representative samples are selected from Chang 8 reservoir of Xifeng oil field of Ordos basin to develop water displacing oil of in-situ sandstone microscopic model and water displacing oil of CT scanning for analyzing the impact of microscopic pore structure on flow mechanism of ultra-low permeability reservoir. The experimental results of water displacing oil indicate the water displacement effi- ciency always presents direct ratio with permeability for the core samples without microcrack. However, the existence of microcrack increases the heterogeneity of microscopic pore structure, then the flow mechanism changes completely, and the water displacement efficiency differs. The laboratory findings of water displacing oil of CT scanning also demonstrate microcraek increases the microscopic heterogeneity of pore structure to some great extent, makes the water displacement effect worse. Casing pressure has major affection on water displacement efficiency of dual porous medium reservoir. It is obvious that the microscopic pore structure heterogeneity is the main reason to cause low sweep efficiency and worse water displacement effects for ultra-low permeability reservoirs.
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2009年第1期53-59,共7页
Journal of Jilin University：Earth Science Edition
基金
国家科技支撑计划(2007BAB17B02)
长江学者和创新团队发展计划(IRT0559)
关键词
微观孔隙结构非均质
水驱油效率
渗流机理
X—CT成像
西峰油田
microscopic pore structure heterogeneity
water displacement efficiency
flow mechanism
X CT imagery
Xifeng oil field
