Analaysis And Countermeasure Of Influencing The System Efficiency Of Pumping Unit Wells

Sucker rod pumping is one of the traditional oil production methods which play a dominant role in petroleum industry, and well pumping unit is the major equipment in crude oil production. With the oilfield development in depth, the production cost is increasing year by year; system efficiency becomes an important indicator of an oilfield development level. Therefore, it is important to study the factors that affect system efficiency and search out the most sensitive factors, which is significant to improve the efficiency of artificial lift system and reduce energy consumption.Energy consumption of sucker rod pumping system is a complex and complicated issues. Both theoretical study and practical results show that there is a close contact between energy consumption and system efficiency. In general, energy consumption is smaller when system efficiency is higher and vice versa. System efficiency reflects the general level of sucker rod pumping technology. There are many factors influencing system efficiency in practical production, which mainly include formation factors, equipment conditions, management level and other constraints. Sucker rod pumping system transforms the electric energy of ground to mechanical energy through related transmission equipments, and lift liquid to the ground. There are energy losses in every subsystem of the whole system. Energy consumption is increasing and system efficiency is decreasing through several links.Statistics show that the national average system efficiency of beam pumping units is about21%, and some well even lows to2.3%, which is far lower than the national average level. The average system efficiency of pumping wells in American California is28.7%. Now the national level of the system efficiency is about of the eighties in last century of America. The study shows that there is great potential energy efficiency and large space for improvement of system efficiency.The main factors that affect system efficiency have been discussed in this paper through testing and anglicizing the system efficiency of well pumping units and studying of improving technology. They include both the ground factors such as pumping units, degree of balance, motors and underground factors including suction parameters, pumps hanging depth and other factors. We did the research on the parameter optimization method as the goal of improving pumping system efficiency and productivity. The main study results are as follows:1. The calculation models of system efficiency of diluting and non-diluting pumping wells were established respectively according to the characteristics of Tahe Oilfield. System efficiency can be expressed as the product of the ground efficiency with downhole efficiency, and we need to improve ground efficiency and downhole efficiency in order to improve the system efficiency.2. System efficiency influencing factors of diluting and non-diluting wells have been analyzed respectively in Tahe Oilfield. The relationship between each factor and system efficiency have been studied mainly from pumping unit, motor, degree of imbalance and negative torque, oil pressure, casing pressure, pump depth, submergence depth, the viscosity of oil, gas, the daily fluid production rate and swabbing parameters. The analysis showed that system efficiency has something to do with each factors in different degree. Generally, system efficiency show increasing of reasonable submergence depth, high pump efficiency, high daily fluid production rate, long stroke, the appropriate pumping units, and good degree of balanced.3. The sensitive analysis of system efficiency factors have been studied according to the characteristics of Tahe oilfield. The result shows that the key factors for non-diluting wells are oil pressure, casing pressure, degree of balance, submergence depth and the diameter of the pump while for diluting wells are submergence depth, pumping speed, motor power utilization and blending ratio, which can provide reference to improve the system efficiency in Tahe Oilfield.4. Evaluation diagram of system efficiency is established respectively based on national average and Tahe average according to the testing results of system efficiency in Tahe oil field, and each block of each plant was evaluated with two average modes.5. Optimization design of pumping wells has taken out according to the production characteristics of Tahe oilfield. Changing the proper diameter of the pump, submergence depth will change the suspension point load; the changes in each parameter should be checked and calculated; only when each parameter is reasonable the swabbing parameter is proper.6. Measures to improve system efficiency of pumping wells were taken from both surface and underground. In order to improve the efficiency of ground, you should select proper pumping unit and motor to make sure that the load and power efficiency utilization are at a high level, and maintain a good balance of the pumping unit.To improve the efficiency of underground you should choose appropriate pump depth, submergence depth, and pumping parameters. To improve system efficiency is a systematic project, only when the most optimal configuration be achieved can the maximize system efficiency be gotten.