(A) Overview With the development of China's oil industry and oilfield development needs, in order to improve oil recovery and ultimate recovery rate, the application of mechanical oil recovery method is an important step in the development of the entire oil field. As a relatively new mechanical oil recovery equipment, submersible pump has been widely used in our country in recent ten years and has been continuously improved and developed. Submersible pump is a multi-stage centrifugal pump working downhole, together with the tubing into the well, the ground power through the transformer, control panel and submersible cables will be delivered to underground submersible electric motor, the motor driven multi-stage centrifugal pump rotation will be The electrical energy is converted to mechanical energy, lifting the well fluid in the well to the surface. As the submersible pump unit and the pump is below the ground more than two thousand meters of the bottom of the work, the working environment is very harsh (high temperature, strong corrosion, etc.), the traditional power supply ----- Total pressure, frequency so that it Frequent faults, operating costs greatly increased. Submersible pump damaged ground mentioned to repair, only a project fee reached 50,000 yuan, the value of one hundred thousand yuan on average put on the cable to be replaced five times, the submersible pump on average every ten months to be Maintenance time, maintenance costs about eighty thousand yuan. For example: 1, the submersible pump at full speed operation, when the amount of fluid is not abundant, easy to take the time to evacuate, or even cause a dead hole, once the dead hole, the loss was heavy. 2, the oil field supply voltage often fluctuates, the motor under excitation or over excitation, the motor is burned from time to time. 3, two thousand meters downhole cable brought about 150V line loss, as part of the loss can not be compensated, thus affecting the normal operation of the motor. (B) the application of submersible pump dedicated inverter Submersible pump in the power frequency start, start current, the larger the voltage drop of the motor cable, making the motor cable in the boot process higher back pressure, so that the insulation performance Lower, each will make the pump life greatly reduced, greatly affecting the life of submersible pump. Submersible pump in normal operation, the prevalence of low motor load conditions, "big car" serious phenomenon. Submersible pump power factor is low, reactive power loss, power consumption and more. According to the requirements of oilfield development program, submersible pump should be based on changes in geological conditions, regulating pumping volume. The traditional way to adjust is to change the nozzle to adjust the output, which not only causes the energy loss but also can not be precisely controlled. Sometimes makes the motor and pump running at high pressure for a long time; sometimes make the well out of the sand serious, shorten the life of the equipment, can not meet the requirements of the development program. To solve the above problems, only the use of frequency control system, adjust the hydraulic pressure, adjust the output. We have over 20 electric pump wells in Shengli Oilfield to transform the frequency conversion operation, played a good effect. Submersible pump dedicated inverter has the following characteristics: 1, the pump can achieve soft start, soft stop, extend the life of the pump, motor protection, cables, saving maintenance costs. 2, improve the power factor of the electric pump system, energy-saving effect is obvious. 3, improve the quality of the pipe network, can realize the closed-loop control of the electric pump system, increase the work safety of the electric pump system. 4, high reliability, easy to operate, you can achieve continuous output voltage and current regulation, in order to achieve the purpose of continuously adjustable output power, the electric pump oil production system in the best working condition. 5, improve production efficiency, facilitate the overall management and dispatch, can realize the pump system of distributed control. 6, oil extraction technology involves multidisciplinary fields, the current submersible pump inverter from the original high --- low --- high mode into a direct high-high frequency, smaller, more convenient operation. Suggestions: In summary, the use of frequency control screen to improve oil production efficiency, while in line with the requirements of the development program. The submersible electric pump shaft is transformed by frequency conversion to realize the soft start of the electric pump well and the soft stop, effectively protecting the electric pump well unit and the cable; the hydraulic pressure can be conveniently adjusted by adjusting the frequency, thereby avoiding the problems that the unit, Long-term operation under high pressure; extend the life of electric pump wells, saving oil well maintenance, maintenance costs, the pump unit in the best conditions to run. Greatly improve the efficiency of electric pump production system. At the same time, improve the power factor, improve the power supply capacity of the power grid, energy-saving effect is obvious. Large-scale promotion of submersible pump frequency conversion technology, will bring good economic and social benefits.