SUCKER-ROD PUMPING UNIT BALANCE DIAGNOSTICS BY WATTMETER CARD

Abstract

The relevance of the research is conditioned by widespread use of unregulated sucker-rod pumping units, equipped only with mechanical adjustment tools. Application of that type of units results in considerable losses of both electricity and crude oil related to machine operating in non optimal regime. To solve this problem both new and already exploited sucker-rod pumping units are equipped with means of intelligent control and monitoring, which are included within control stations equipped with frequency converter and controller. Implementation of these tools on sucker-rod pumping units control station controller requires the development of appropriate algorithms to ensure autonomous, high performance, cost-effective and reliable function of plant during all life cycle. The main aim of the research is elaboration of the algorithms for determining pumpjack balance, optimal counterbalance position and polished rod dead centres passing moment. Objects of the research are the sucker-rod pumping unit in different operating modes and pumpjack balance, defined by the counterbalance position on the crank. Methods: mathematical analysis tool of differential equations and transfer functions, computer simulation, comparison and analysis of charts and diagrams. Results. The paper considers the existing ways of pumpjack balance detection and their shortcomings. It turns out that wattmetering is the most available and fail-safe sucker-rod pumping unit condition monitoring method which does not require installation of additional external sensors. The authors have developed the sucker-rod pumping unit computer model for investigating principles and load cycles of unit operation. Based on the data obtained by simulations the authors developed the algorithm of pumpjack balance detection, which can work as sucker-rod pumping unit intelligent control station software ensuring easy control, timely service and cost reduction.

Keywords

• oil industry
• sucker-rod pumping unit
• pumpjack
• induction motor
• frequency converter
• controller
• intelligent control station
• wattmeter card
• balance ratio
• counterweight
• dead centre
• diagnostics