Simulation Of Cyclic Hot Water Stimulation Of Heavy Oil Wells

Thermal recovery is the most important way to improve heavy oil recovery. Hot waterstimulation of heavy oil producing wells has been employed at home and abroad,with variedsuccess. The process is similar to that involved in cyclic steam stimulation. It is likely to beless effective on account of the smaller heat carrying capacity of water as compared to steamon a unit mass basis.On the other hand,hot water offers certain advantages;for example,salinehot water permits the use of a much higher injection pressure than for steam,for a giventemperature. Cyclic stimulation of heavy oil producing wells by hot water has been employedat home.In this process,a predetermined volume of hot water is injected into a well,followingwhich,the well is put back on production.As a result of the decrease in oil viscosity in thevicinity of the wellbore,as well as wellbore clean-up,oil production rates usually show anincrease.The present work was devoted to the numerical simulation of the above process.Theequations for mass and heat transport,for two-phase flow in a two-dimensional radial flowsystem,allowing for gravity,capillarity,and directional permeability effects,were formulatedand solved.The differencing technique employed a linearized Semi-Implicit Scheme,solvingfor one of the phase pressures and saturations simultaneously.The resulting differencingequations were solved by the iterative ADIP,as well as SIP.Experience using these techniquesshowed that whereas SIP was highly effective for the injection phase of the problem.ADIPwas more efficient for the fluid production phase.Use of either scheme for both injection andproduction required the use of prohibitively small time steps,in spite of the implicitformulation used.The principal difficulty was the large contrast in the block transmissibilitiesarising from the grid used. The heat transport equation was solved by SOR and ADIP.Theresults,in this case,were very similar for the two methods.Stability criteria were obtained forthe heat and mass transport equations on the basis of the computational results.This model can be used to solve various cases of hot water stimulation..To test thestability and the sensitivity of the model,this article selects the Qi40Block of Liaohe oil fieldformation condition water injection speed was used in the model,studying the effectiveness ofrelative permeability, thermal conductivity coefficient, reservoir thickness, water injection,shut-in time, initial oil saturation temperature and viscosity of crude oil on oil production andrecovery factor. Upon examination, the model can be used to assess water stimulation effectof heavy oil.