Design Optimization of Sucker Rod Downhole Pumps Regarding Components and Material Selection
Research output: Thesis › Master's Thesis › Research
The aim of this master thesis was to analyze the optimization potential of the RAG sucker rod downhole pumps. In a first step a literature research was carried out in order to get familiar with the major problems that downhole pumps face such as wear, corrosion etc. Additionally, a market study was done to get an overview of available design possibilities, materials and innovations. Last but not least the performance statistics and the design of the RAG sucker rod pumps were analyzed to get a baseline for the possible run time improvements in the future. A detailed analysis of the downhole failures, such as tubing leaks, pump-, paraffin-, and sucker rod failures over the last 15 years already showed a significant reduction and an increasing run time. Despite that, 50% of the failures in 2015 were pump related failures, therefore every single pump component was considered in detail by looking at the pump repair data to improve and possibly redesign them. In the end it turned out that the most critical parts are the valves, the barrel and the plunger. Based on these results, possible solutions and measures were categorized according to the effort and duration of research and field implementation. The short-term recommendations concern improvement of the relatively soft cobalt alloy valves ball and seat material to harder and much more abrasion resistant materials. The mid-term measures address barrel and plunger wear. To extend the barrel and plunger lifetime a barrel surface coating which is more resistant to corrosion, abrasion and environmentally friendly could be used. Regarding the plunger there are various designs available on the market, which could reduce the wear like the Three-Tube pump or the FARR plunger. The long-term optimization projects are the evaluation and test of a pump design called Samson Pump to handle abrasive fluids efficiently or a research cooperation of the coating process of valves with Hardide, a very hard and nano-structured tungsten carbide layer which offers superior abrasion, erosion and corrosion resistance. Furthermore, there is additional optimization potential to increase the pump efficiency, like a re-design of the valve rod guide to minimize the flow restrictions or a bottom discharge valve to reduce the resistance on the downstroke.