Research On The Performances Of Screw Pump Direct-drive Equipment And System Optimal Design

As a new artificial lift method,oil production by screw pump has become one of the major methods and plays a significant role in the worldwide oilfields for its unique advantages including few moving link,low cost,great suction behavior,high system efficiency and so on.However,it is not making the full use of screw pump advantages because of the lack of study on screw pump operating performances and the complicated conventional drive method in current screw pump system.In order to improve the efficiency of screw pump oil wells,Daqing Oilfield has successfully developed a direct-drive equipment for screw pump,adopting low-speed and high-torque direct-drive motor to rotate the pumping rod,eliminating the original intermediate reducing mechanism such as belt drive and gear reducer,and further improve the output efficiency of the motor.With the widespread application of screw pump and more efficient performances of direct-drive screw pump,optimal design of direct-drive screw pump will be conducive to its universal application,improve the efficiency of the direct-drive screw pump system and reduce its energy consumption.Establish an optimal design mathematical model for direct-drive screw pump system through the researchs on oil well inflow characteristics,screw pump outflow characteristics and direct-drive motor operating characteristics,taking the highest efficiency of direct-drivescrew pump system as the objective function.Optimize the parameters of direct-drive screw pump system to make the system run efficiently and reduce the cost of oil exploitation.Get the screw pumps characteristics curves and the load-efficiency curves of direct-drive motors through experimental data,and fit the curves into polynomial expressions.Use VB programming language to develop an optimal design program of direct-drive screw pumpsystem,the direct-drive screw pump wells are optimized with direct-drive motor type?rotating velocity,screw pump type,pump rod type and pump installation depth and other parameters,establish a set of scientific method of direct-drive screw pump system optimal design.Designing two direct-drive screw pump wells to compare with the program computing results,the efficiency is increased by more than 11%.Optimal design of direct-drive screw pump wells will contribute a lot to improve screw pump system efficiency,reduce oil production costs and energy conservation.