The Design Of Mechanical Stepless Speed Regulation Drive Device And Automatic Control System For PCP

The recovery technology and drainage equipments for CBM wells are the importantfactors to ensure long-term continuous stable drainage of CBM wells. The Progressing cavitypump systems in CBM production wells are widely used because of the advantage of PCPsystem in displacement regulation, anti-sand and handle gas. In this paper, based on theanalyses of recovery theory, recovery characteristics and requirement of drainage equipments,with the goal of improving the adaptability of PCP systems in CBM production wells, thedrainage technologies of PCP systems were studied.This paper first analysed the composition of the Progressing cavity pump system and itsadaptability in CBM production wells. According to the the CBM wells production practices,the problems of PCP drainage systems were analysed, and the influence on the performanceof PCP system were analysed from handling the solid handling the gas, pump off control andpump depth selection. And some appropriate improvements were proposed.Based on the particularity of CBM wells drainage, stepless speed regulation technologywas proposed in order to improve the adaptability of PCP system. Adopting stepless speedregulation technology, the operating parameter of PCP system can be adjusted continuously,in order to adapt to different displacement of CBM wells in different drainage stage, andreduce the drainage interrupt caused by step speed regulation or the operation for pump typereplacement, and enhance the ability to control dynamic fluid level and bottom-hole flowingpressure and the ability for controlling pump off. The drainage efficiency and adaptability ofPCP system could be improved effectively.The design scheme of mechanical type stepless speed regulation is proposed for PCP system driven by gas engine. In the design, Wide V-belt type stepless speed transmissionmechanism is adopted to achieve stepless speed regulation for PCP system, and the range ofspeed regulation, the driving capacity and the operating characteristic are analysed. Thesurface mechanical stepless speed regulation drive device for PCP system is designed. Basedon intelligent control principle and the control for bottom-hole flowing pressure in CBMwells, automatic speed control system is designed for the mechanical stepless speed regulationdrive device. It can achieve automatic speed regulation for PCP system, and the intelligentadjustment for drainage system in CBM production wells.