摘要
油水饱和泥质砂岩中流动电位的研究对于揭示含油储层震电勘探和动电测井的机理有着重要的意义.本文首先从岩石孔隙的微观结构出发,构造了描述水润湿条件下油水饱和泥质砂岩储层的毛管模型.在模型中依据油水流动遵守的Navier-Stokes方程和电化学传质动力学理论,建立了描述油水饱和泥质砂岩流动电位的数学方程,并数学模拟了岩石储渗参数对流动电位频散特性的影响规律.研究结果表明:储层孔隙内流体受到的粘滞力与惯性力控制着水相和油相的流动,从而决定了流动电位的频散特性.随着孔隙度的增大,油水两相各自的有效渗透率均增大;而含水饱和度的升高使得水相有效渗透率增大,油相有效渗透率减小.在水润湿条件下,流动电位耦合系数随含水饱和度升高而增大,随束缚水饱和度的升高而减小.另外,流动电位相对耦合系数也随含水饱和度的升高而增大,但无频散现象.
It is well known that utilizing the seismo-electric prospecting and electrokinetic logging could obtain the more formation information including porosity, permeability and water saturation which are the most important parameters to evaluate the hydrocarbon. And the study of frequency- dependent streaming potential in oil-water bearing argillaceous sandstone can help geophysicist understand their microscopic mechanism. But it is very difficult to quantitatively describe the phenomenon because of the complicated pore-throat structure, the distribution of oil and water in the pore, and the influence of wettability. To solve the problem, this paper firstly created a new capillary model considering water wettability to describe oil-water bearing the rocks according to its microscopic pore structure, and gave the conversion formulas between macroscopic transport parameters of the reservoir rocks and microscopic parameters of the capillary model. Then, based on the solution of Navier-Stokes equation obeyed by the water and oil flow, respectively, and combined with the theory of electrochemistry transfer dynamics, the mathematical method to describe the frequency-dependent streaming potential was established. Finally, quantitatively analyze the influence of water saturation on the frequency response of streaming potential. This results show that the frequency dispersion characteristics of streaming potential are dependent on interaction between the viscous force and inertial force because that they control the fluid flow. Both of oil-phase and water- phase effective permeability increase with the increasing of porosity. The higher water saturation increases the water- phase effective permeability and decreases the oil-phase effective permeability. With the water-wet condition, the coupling coefficient of the streaming potential increases with the increasing of water saturation, and decreases with increasing of irreducible water saturation. Additionally, the relative coupling coefficient of streaming potential also increases with the increasing of water saturation, and doesn＇ t have dispersion phenomenon.
出处
《地球物理学进展》
CSCD
北大核心
2014年第1期291-299,共9页
Progress in Geophysics
基金
国家自然科学基金项目(41174101)
山东省自然科学基金项目(ZR2011DM002)联合资助
关键词
油水饱和泥质砂岩
流动电位
毛管模型
有效渗透
率频散特性
oil-water bearing argillaceous sandstone
streaming potential
capillary model
effective permeability
frequency dispersion characteristics
