Rational Matching Injection and Production Pump for Rod Pump Injection-Production Systems

Single-well injection-production technology is an effective measure for stabilizing oil and water control of the high water cut oilfield. The rod pump injection-production system uses gravity to separate oil and water under the well; throught two sets of rod pumps, the water is injected back into the formation and the concentrate is lifted to the ground. Because of the particularity of pump structure and the complexity of its working environment, the calculation method of 1st pump efficiency is quite different from that of conventional pumps. Reasonable matching of the production pump and the infection pump is the key factor to reduce the water cut of the produced liquid. Based on the gas PVT theory and the principle of mass conservation, the gas volume equation of the down well was established in this paper, and the calculation method of pump efficiency of single well injection-production system was established, which was verified and corrected by 17 field test wells, with considering the influence of pump stroke loss and leakage. Combining the established mechanical model of the single-well injection-production system, aimed at the lowest water cut of the produced fluid, we use the enumeration method to design a reasonable matching of the production-injection pump and suction parameters, and formulated the selection template of production-injection pump type and the selection of the working system for the rod pump single-well injection-production system. It provides a basis for the process design of the single-well injection-production system and provides technical support for the field application of the fourth generation oil recovery technology.