油藏物理学油藏物理学 (20).ppt

9 Flow Systems of Simple GeometryHorizontal Flow.（水平直线流）（水平直线流）Horizontal rectilinear(直线的）直线的）steady-state flow is common to virtually all measurements of permeability.Radial Flow.（径向流）（径向流）A radial-flow system,analogous（相似的）（相似的）to flow into a wellbore,is idealized in Fig.re the radius at which Pe is measured；rw the radius at which Pw is measured.1).Consider the case where the flow system is comprised of layers of porous rock separated from each other by infinitely thin impermeable barriers as shown in Fig.Parallel combination10 Average permeability of combinationlayersLinear flow直线流直线流并联组合并联组合 Radial flow Qt=Q1+Q2+Q3ht=h1+h2+h32)Another possible combination for flow systems is to have the beds of different permeability to be arranged in series as shown in Fig.series combination串联组合串联组合Qt=Q1=Q2=Q3Linear flowP1-P2=P1+P2+P3Radial flowRadial flow-series combinationP1-P2=P1+P2+P3Qt=Q1=Q2=Q31)Bundle of capillary tubes pack毛细管束模型毛细管束模型10 The relationship of permeability and other property of rock Fig.parallel bundle of capillary tubes pack Consider a system comprised of a bundle of capillary tubes of the same radius and length;The equation for flow of fluids in circular conduits:流体在圆管中的流动公式流体在圆管中的流动公式qthe volume rate of flow,cm3/s fluid viscosity,mPa.s(P1-P2)pressure loss over length L,ro radius of capillary tube,cm,Poiseuilles equation2)The relationship of permeability and pore radius If the fluid-conducting channels in a porous medium could be represented by a bundle of parallel capillary tubes of same diameters,then the flow rate through this system is:nnumber of capillary tubes per unit cross-sectional arearradius of capillary tubeA total cross-sectional area From Darcys law it is also known that:Equating Darcys and Poiseuilles equation:(1)By definition,the porosity is(2)Therefore:(3)3)The relationship of permeability and specific surface surface area S is the total area exposed within the pore space per unit of bulk volume.Let Sp be the internal surface area per unit of pore volume,Ss be the total area exposed within the pore space per unit of grain volume Gaocaini-EquationEXAMPLE 1 A core sample from a uniform sandstone formation has a permeability of 480 10-3 m2 and a porosity of 0.17 Estimate:(a)The average pore throat radius of the core.(b)Specific surface areas Sp and Ss.problem1.What is permeability of rock?What are the conditions that shoud be met when measuring absolute permeability of rock?:2.What phenomenon will appear when using gasto measure permeability of reservoir rock?How does it influence the result of measurement?3.一个油藏注入污水后渗透率下降，请设计一室内渗一个油藏注入污水后渗透率下降，请设计一室内渗透率测定实验，研究注水前后渗透率的变化。写出实验透率测定实验，研究注水前后渗透率的变化。写出实验方案，实验原理，画出流程图。方案，实验原理，画出流程图。