裂缝性油藏渗吸采油机理数值模拟  

Mechanism simulation of oil displacement by imbibition in fractured reservoirs

作　　者：王敬[1] 刘慧卿[1] 夏静[2] 刘月田[1] 洪铖 孟庆帮 高阳[3] 

机构地区：[1]中国石油大学(北京)油气资源与工程国家重点实验室,北京102249 [2]中国石油勘探开发研究院,北京100083 [3]中国石油新疆油田公司,新疆克拉玛依834000

出　　处：《石油勘探与开发》2017年第5期761-770,共10页Petroleum Exploration and Development

基　　金：国家自然科学基金(51504264);国家重点基础研究发展计划(973)项目(2015CB250906);中国石油科技创新基金(2015D-5006-0204);中国石油大学(北京)科研基金(2462014YJRC028)

摘　　要：基于渗吸采油机理和渗流理论,建立考虑重力和毛管压力的静态和动态渗吸机理数学模型,并利用室内实验数据验证了模型的可靠性,然后利用该模型研究了原油黏度、基质渗透率、岩块尺寸、界面张力以及驱替速度对渗吸采油的影响。研究表明:渗吸采收率随原油黏度增加而降低,黏度越小,初期渗吸速度越快;基质渗透率与渗吸采出程度正相关,低渗油藏至致密油范围内渗吸采油效果差异显著;岩块尺寸与渗吸采出程度负相关;不考虑重力时,界面张力较低导致渗吸采油无法发生,考虑重力时,超低界面张力下渗吸采油也能发生,总体呈现出随着界面张力降低渗吸采收率先升后降的趋势,并且不同界面张力范围内毛管压力和重力的作用存在差异;裂缝性油藏驱替速度存在最优取值范围,应在保证产油速度的条件下优选驱替速度以获得较高采收率。The mechanism model of both static and dynamic imbibition considering capillary pressure and gravity was presented based on the imbibition mechanisms and seepage theory. The validation of the model was performed using published experiment data. Then, this model was employed to study the impacts of oil viscosity, matrix permeability, core size, interface tension, and displacement rate on imbibitions. The results show that, the recovery decreases as oil viscosity increases, and the initial imbibition rate is much faster for lower viscosity oil. Imbibitions recovery is positively related to matrix permeability, the differences ofoil recovery for low-permeability to tight oil reservoirs are obvious. Imbibitions effect is negatively related to core size. If the interface tension is low, imbibitions cannot occur without consideration of gravity. But it can occur even in very low interface tension scenario with consideration of gravity. On the whole, the recovery first increases and then decreases as the interface tension decreases. The gravity and capillary play different roles at different ranges of interface tension. There exists an optimal value range of displacement rate in fractured reservoir, which should be optimized with a sufficient oil production rate to achieve higher recovery.

关 键 词：裂缝性油藏 静态渗吸 动态渗吸 渗吸机理 影响因素 

分 类 号：TE349[石油与天然气工程—油气田开发工程]