Study On Production Optimization And Working Condition Diagnosis For Carbon Fiber-steel Rod Pumping System

The carbon fiber composite continuous sucker rod has been widely used in oilfields based on its advantages of low density,high intensity,decreasing the polished rod load,increasing the pumping depth and corrosion resistance.But the studies of the design of sucker rod and the optimization of production parameters and working condition diagnosis on the carbon fiber-steel sucker rod system are simple and imperfect.In view of the above problem,the paper first summed up the influence of carbon fiber sucker rod on production conditions by using the field data and compareing with the conventional sucker rod wells.The results show that the maximumpolished rod load,the minimum polished rod load,the maximum torque and the polished rod horsepower of carbon fiber system were reduced by 39.3%,63.9%,49.2%,20.7%.The effective power and the system efficiency were increased by 24.0%and 8.41%,the electricity consumption per hectometer ton liquid was reduced by 1.09 kW.h when the production were same,the showed that carbon fiber sucker rod system is beneficial to reduce the energy saving.On the basis of previous studies,the paper built the carbon fiber-steel mechanical model and selected the calculation method of model parameter with the date of 3 test wells in shengli oil field.The average error of predict result were below 5%.The rods of 7 test wells were safe after rod checking.It built the cauculate model of graph of pump work based on the Gibbs equation using the date of surface dynamometer card.It cauculated and analysed 7 kinds of typical working condition characteristics,compared with the the steel rod system.It showed the load of carbon fiber rod system are smaller and the stroke loss are bigger than steel rod system,but other characteristics are similar to basic steel rod system.The paper selected the pump diameter,depth,stroke and the number of punching to to analysis the influence on the pump efficiency and the efficiency of the system by using the test result of test well 4~#,3 test wells of shengli oilfield predict feasible scheme and working condition were studied,the scheme were optimized based on the carbon fiber-steel rod pumping system optimization design software.The studies have shown that the stroke,number of punching had the spaces to regulation.It has provided a theoretical guidance and basis to improve the efficiency of carbon fiber rod system.The study calculated the graph of pump work from the surface dynamometer card according to the Gibbs equation,selected the combining method of vector method and rule-based diagnosis method to identify the indicator diagrams features.It diagnosised 2 test wells of shengli oilfield with failure and 5 different time indicator diagrams of a normal test well and 7 kinds of typical working condition diagnosis indicator diagrams,the main working condition were accurately diagnosed.It provided the theoretical support and technical supportf for carbon fiber-steel rod pumping system working condition diagnosis.