Study On Reservoir Temperature Field With Numerical Simulation

Exploitation of reservoir is a non-repetitive process, and any error in the process will be irretrievable, but it is very easy to calculate the exploitation process of various exploitation plans by using reservoir simulation, then find the exploitation plan of maximum economic benefit from calculated results. As an important tool of oil-field development and scientific decision-making, reservoir numerical simulation is used to explore all kinds of complicated filtering flow in porous medium in theory, and design development program, dynamic monitoring, development adjustment and so on in engineering. Therefore, it can provide theory basis for making technical measure in oil-field development. The intention of researching on reservoir numerical simulation is, accurately predicting the development dynamics of oil reservoir, finding optimal scheme of exploitation plans, reducing exploitation risks to its minimum and enhancing economic benefits of reservoir development. With the price of crude oil going up and the raising cost of development, Oil-field development requires more for studying of theory and software. In order to raise the certainty of pre-determination and accuracy of numerical reservoir simulation, this paper researched the temperature field of reservoir during the process of reservoir development, and launched the numerical simulation method of coupling temperature field, and developed mathematical model of coupling reservoir numerical simulation on the bases of numerical reservoir simulation theory which are now available.On the bases of present nonisothermal filtering flow, heat transfer in porous media and reservoir simulation, the paper developed the following research work:(1) Analyzed the key factors which affect reservoir temperature field. These factors are: the geothermal gradient of original reservoir, the temperature of flooding and filtering flow during the process of development;(2) According to the law of heat transfer and seepage flow in porous medium, a mathematical model of coupling temperature field was established. The process of reservoir development is a process of heat transfer and mass transfer in reservoir of porous medium, and the physical property of fluid in porous medium varies with the temperature, at the same time, the flowing of fluid affects the changes of temperature field, these are the fundamental causes which form the coupled heat transfer and mass transfer. In this paper, emission of heat radiation and fluid diffusion which are accessory coupling factors are omitted, but it is stressly researched that the coupling process of heat conduction, heat advection and filtering flow during the course of reservoir development, and a mathematical model of numerical simulation is established.(3) Achieved the solution of multi-field, strong coupling, highly nonlinear mathematical model of reservoir numerical simulation by finite difference numerical method.The mathematical model of coupling temperature field distinguishs traditional model. After difference divergence, many highly nonlinear equations are developed at node point of every grid. This paper linearized highly nonlinear equation group by adopting fully implicit difference method, then jointly computed the equation group which included 4N equations. Therefore, we removed the time lag phenomenon in sequential solution, and achieved the coupling of multi-field.(4) Reservoir simulation programs are designed and developed in C++ language. By adopting module program design method and adding program design ideas which are object oriented, we optimize program organization and decrease the difficulty of composing codes.(5) Systematically studied the coupling between heat transfer and seepage flow in reservoir simulation by numerical simulation method, and researched the effects of flooding temperature on saturation , producibility, water injection rate , the formation pressure , and researched the effects of geotemperature on production well by numerically simulating geological model. At the same time, examine the feasibility of theory research and program design.The results of reservoir numerical simulation obtained in the paper show that reservoir numerical simulation of coupling temperature field can actually simulate the reservoir changing process during reservoir development and enhance the certainty of reservoir numerical simulation.