Design And Study Of The Progressing Cavity Pumps Used In An Efficient Pressure Regulation Water Injection System

This paper study the efficient pressure regulation system for stratified water injection,which comes from the condition that many injection wells come to the later stage of itslifetime and the injection pressure needed become higher. In other words, this is a new type ofwater injection system with an increasing pump. It uses a progressing cavity pump and aprogressing cavity motor to boost and reduce the water with a differential pressure on thebasis of the original pressure of the injection net, and the outlet pressure could satisfy therequirement of two injection layers respectively.The use of the progressing cavity pumps and progressing cavity motors in waterinjection system have the same fundamentals of progressing cavity pumps used in oilproduction and mud motors in drilling tools, and it comes from the innovation in structure.The significant meaning of this system lies at no changing to the original water injection pipelines, and it does not need extra energy sources to achieve the pressure regulation to get ahigher and a lower pressure at the same time with a progressing cavity pump and aprogressing cavity motor. And the water with different pressure is injected into two layersrespectively. As for those injection wells that were far away and not convenient to access anyenergy sources, this kind of system is a good project to meet the injection requirement with anespecial high pressure. And other advantages of this system have something to do with itsinstallation location. Since the whole downhole unit is installed in the bottom of the well, itrelieves work against the steal of the equipment. And a downhole unit does not release muchnoise that may harm the surroundings on the opposite condition. At the same time, it does nottake any ground space or harm the environment due to the discharge or leakage of the boosterpump. In this paper, the whole unit is designed to be used in a5-1/2in casing well. It containsthe structural design of the progressing cavity pump and the progressing cavity motor, and thecalculation of the structural and dynamic parameters. Through the analysis of the matchingdynamic parameters between the progressing cavity pump and the progressing cavity motor,three coordination equations are derived, that is the coordination of torque, the coordinationof flow, and the conservation of energy. These three equations are the foundations for thedesign of the efficient pressure regulation system through the use of progressing cavity pumpsand progressing cavity motors, and these are the guides to design a matching system withcoordinate torque and flow.The analysis shows that this system could work at a quite wide range for the differentialpressure and the flow. But the structural design of the system has to be change according tothe result of the three coordination equations. This system has suitability to the changes of theinjection layers with appropriate pressure and flow regulation equipment.