Numerical Simulation Research Of Foamy Oil In The Heavy Oil Cold Production

A number of heavy oil reservoirs under pressure depleted by cold heavy oilproduction with sand (CHOPS) show anomalously good primary performance.Foamy oil behavior is validated to be one of the reasons. Based on former researcheson production mechanism, the paper investigate the dynamic progress of gas phaseevolution in foamy oil including the nucleation, bubble growth and coalescence.Previous researches on numerical simulation of primary depletion in foamy oilreservoirs aim only at empirical improvement on the conventional dissolved gasdrive models, but neglecting a complex interplay of several rate processes in foamyoil flow. Based on the basic experiments on foamy oil and primary depletionexperiments, the paper investigates the characteristics of foamy oil and productionperformances on the foamy oil flow, and then presents a numerical model includingthe non-equilibrium rate processes related to the nucleation, bubble growth andcoalescence which are the major mechanisms of the foamy oil recovery. Theproposed model was used to match the primary depletion tests in a laboratory scalesand pack, and investigate the effects of various process parameters on oil recovery.It was observed that the solution gas drive recovery factor increased dramatically asthe rate of pressure decline was increased.