Reservoir Fluid-solid-heat Coupling Model Research And Preliminary Application

Flow of fluids through porous media exists in many engineering problems including petroleum engineering. Study on this problem has been experienced from none coupling to coupling. None coupling is simple mechanic study of fluid flowing in porous media without considering mutual interaction between fluid flowing and rock deformation while fluid-solid coupling compensates this defection. The fluid-solid coupling model furthers explosion of the law of seepage and rock deformation more accurately compared with none coupling model. However, temperature field is generally assumed as Constance or coupling among temperature field variation and rock deformation and fluid seepage is not considered in the fluid-solid coupling theory. It should be admitted that actual temperature field of fluid-solid coupling systems existing in nature usually varies. Especially there are large amount of fluid-solid coupling systems with dramatic temperature variation, such as geothermal utilization system and thermal production system in the petroleum industry. As to this kind of problems , it is obvious that to simulate the principal of seepage, deformation and temperature variation still following fluid-solid coupling model is no longer accurate, due to rock deformation led to by thermal effect and fluid pressure in multiple pores, temperature field variation caused by rock deformation and flow of fluids in porous media, and changes of storage permeability characteristics and fluid pressure in multiple pores led to by rock deformation and thermal effect. Therefore, it is necessary to consider and develop the fluid-solid-heat coupling theory embracing the above-mentioned couplings among fluid, solid and heat. In order to simulate the chief law of seepage, rock deformation and temperature field variation precisely andprovide exact principal parameters of flow field, lithomechamic field and temperature field, seepage mechanics and lithomachanics and thermodynamics should be combined to set up reservoir fluid-solid-heat coupling model. The theory and application of reservoir fluid-solid-heat coupling in China just begin on the groping stage.The coupling relationship of fluid , solid and hot field and their coupling mechanics and integrated point are.deeply and systemically analysesed and researched in this article. Basic character and coupling relationship of reservoir fluid-solid-heat coupling problem is established in this article. A suit of research method about reservoir fluid-solid-heat coupling is established in this article. Two kinds of mathematic model of non-complete and complete reservoir fluid-solid-heat coupling are devised and established based on fluid-solid mechanics theory,on heat-elastic deformation coupling mechanics theory and on thermodynamics. The first kind of model is non-complete coupling one and this model includes fluid coupling seepage model equation , thermal strain model equation ,and rock coupling deformation equation . The second kind of model is complete coupling one and this model includes the coupling temperature field equation, fluid coupling seepage model equation, rock coupling deformation equation. This two kinds of model have advantage and disadvantage respectively and this two kinds model can describe the course of hot-fluid-solid coupling independently and thus simulate the law of fluid seepage, rock deformation and temperature field change in reservoir with difficult temperature and deformation more exactly.For the first kind of model, model numerical solution method by connect finite element method with finite difference method are established . For the first time,Numerical simulation method of hot-fluid-solid coupling model established in this article and the ABAQUS finite element soft are applied to simulate thermal reservoir, and make a series of parameter/index analysis that have great influence on formation damage and oil production, they are : horizontal displacement analysis , vertical displacement analysis, pore indexanalysis, IPR analysis. Every parameter/index above are cal...