裂缝-孔隙型双重介质油藏渗吸机理的分形分析  

Fractal analysis of spontaneous imbibition mechanism in fractured-porous dual media reservoir

作　　者：蔡建超[1,2] 郭士礼[2] 游利军[1] 胡祥云[2] 

机构地区：[1]油气藏地质及开发工程国家重点实验室,西南石油大学 [2]中国地质大学地球物理与空间信息学院,武汉430074

出　　处：《物理学报》2013年第1期220-224,共5页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2010CB226705);国家自然科学基金(批准号:41102080);西南石油大学油气藏地质及开发工程国家重点实验室(批准号:PLN1117)资助的课题~~

摘　　要：低渗透油藏常常伴随裂缝发育,形成裂缝-基质双重介质.自发渗吸是低渗裂缝性水驱油藏的重要采油机理,有顺向和逆向两种渗吸方式.基于基质孔隙结构的分形特征,引入分形几何对裂缝性双重介质渗吸机理的判据进行了改进,建立了渗吸机理的分形判据模型,并进一步推导了结构常数的解析表达式.结果表明,渗吸机理的判别参数是基质孔隙度、高度、孔隙分形维数、流动迂曲度、最大孔隙直径、界面张力、油水密度差以及接触角的函数.改进后的判据模型与现有结果一致.最后绘制了判别渗吸机理的图版,为利用表面活性剂提高低渗透油藏采收率提供理论依据.Low permeability oil reservoirs are usually accompanied with fracture development, forming fracture-matrix dual porosity medium. Spontaneous imbibition is a crucially important recovery mechanism in naturally fractured reservoir with water deriving, in which non-wetting phase is displaced in either co-current or counter-current manner. In this work, the criterion （inverse bond num- ber） and fractal model for spontaneous imbibition mechanism of dual-porosity medium are developed, and the analytical expression for structure constant is also derived based on the fractal characteristics of pores in porous matrix. The improved fractal model for inverse bond number can be expressed as a function of porosity, pore fractal dimension, flow tortuosity, maximum pore diameter, height of matrix, density difference between oil and water, interracial tension and contact angle. The present model predictions are shown to be in agreement with the available results. The dominion for criterion of imbibition mechanism is plotted, which provides a theoretical basis of adding surfactant in water for enhancing oil recovery in low permeability reservoirs.

关 键 词：双重介质 自发渗吸 渗吸机理 分形 

分 类 号：P618.13[天文地球—矿床学]