Calculation of the Critical Liquid Production of Cyclic Steam Stimulation in Heavy Oil Reservoir with Edge Water

Abstract For heavy oil reservoirs with edge water, when the liquid production of cyclic steam stimulation is excessively high, there is a risk of edge-water invasion. Therefore, the liquid production of cyclic steam stimulation is of great significance to the prevention of edge-water invasion in heavy oil reservoir with edge water. Currently, many studies on the critical liquid production in oil reservoir by water flooding are conducted. However, there is few research on the critical liquid production in heavy oil reservoir by cyclic steam stimulation. To fill this gap, The formation after cyclic steam stimulation is divided into the heated zone and the unheated zone. A characterization method for the flow field parameters after cyclic steam stimulation is established. By transforming the length of the thermal swept zone, the comprehensive mobility of the heated zone is equivalently represented as the comprehensive mobility of the unheated zone. On this basis, considering the threshold pressure gradient in heavy oil, a calculation method for the critical liquid production after cyclic steam stimulation in oil reservoir is developed based on the theory of mirror reflection and the superposition of potentials. The results show: (1) Permeability being constant, the critical liquid production rate increases with the increase in cyclic steam injection quality. With a constant cyclic steam injection quality, the critical liquid production rate increases with the increase in permeability; (2) Guided by the established relationship curve diagram between critical liquid production and crude oil mobility, the development plan is designed. As a result, the comprehensive water cut in the oilfield is 8.1%, and no water invasion has occurred; (3) Guided by the established relationship curve diagram between the cumulative liquid production and cumulative heat injection corresponding to different critical liquid production rates, adjustments were made to the oilfield development plan. As a result, the critical liquid production rate for well A1 increased from 110 t/d in the first cycle to 150 t/d in the second cycle.