The Application of Screw Pumps in Oil Fields
With the development of science and technology, mechanical oil extraction has played an increasingly important role in oil extraction. Compared with the traditional manual operation, its technology is more mature; operation is more convenient, and its performance is more stable.
The current types of screw pumps in China
Under the current situation, China's screw pumps are mainly divided into two kinds, ground driven single screw pumps and submersible motor driven screw pumps, which are currently the two major oil extraction systems in China. The former mainly uses the power of the ground to drive the sucker rod string to rotate, and eventually the rotor rotates at a low speed for live mining. The latter is mainly driven by the submersible machine in the well to directly drive the screw pump for oil extraction.
Working characteristics of screw pumps
As the main system of oil extraction in China, screw pumps have unique working characteristics and working principles. Working characteristics of the screw pump are described in three aspects such as the volumetric efficiency, stator profile and magnitude of interference.
1. Volumetric efficiency of screw pumps
The East China University of Petroleum in China has conducted a project study on mechanical mining. The test content mainly involves the influence of the two factors of medium temperature and viscosity on the working characteristics of the screw pump. Through experiments, it was found that the obvious influence of medium temperature and viscosity on the screw pump is the volumetric efficiency of the screw pump. In this study, a certain numerical simulation was carried out on the actual working characteristic curve of the screw pump, and the influence of stator rubber swelling of screw pumps on volumetric efficiency was tried to be discussed. A large number of research results show that structural optimization of the structural and working parameters of the screw pump can significantly improve equipment loss and extend the service life and working cycle of the screw pump.
Through analysis, it was also found that the actual service life of the screw pump for oil extraction often depends on the oil resistant rubber performance of the stator bushing, and the rubber stator is affected by many factors and directly affects the working characteristics of the screw pump. Nitrile rubber is used in the study at home and abroad. The modified rubber derived from nitrile rubber is also very effective in improving the service life of the screw pump.
2. The stator profile of the screw pump
On the basis of analysis and research, Yusheng Yang and others of Shengli Oilfield in China proposed a simple correction method of the stator profile to improve the accuracy of the bushing profile to improve the sealing performance. The operation is very simple. In order to fully ensure the bushing type of the stator rubber, it is believed that when the stator core is designed, the rubber should be modified according to the different formulas of the rubber, so as to enhance its stability and ensure the molding line of the rubber bush to a large extent.
With the development of technology, wireless geometry and physical linearity especially have played an important role in the detection of limitations of rubber materials. Among these methods, the finite element solution method is commonly used. Rubber has incompressible elastic material deformation. Dr. Shi in China conducted a validity study and introduced Pann invariant decomposition into rubber based on this research, which plays an important auxiliary role in enhancing the stability and convergence of the displacement solution.
3. Magnitude of interference of screw pumps
Through research, it was found that the stator lead, rotor diameter and eccentricity of the screw pump have a certain internal correlation. Only by realizing the reasonable value of each structure, can it ensure existence and effective operation of the screw pump. The main structure parameters of single screw pumps are optimized on the basis of ensuring high efficiency and long cycle working time. Through experiments, experts and scholars have concluded that magnitude of interference between the stator and rotor will greatly affect the actual work of the screw pump. Even if we can reduce the volume loss by reducing the magnitude of interference, it will also cause the increase in mechanical loss. Of course, the above analysis is only applicable to low-pressure head screw pumps, not suitable for all types of screw pumps. Now the high-pressure head screw pumps for oil extraction still need further research and analysis.
The current types of screw pumps in China
Under the current situation, China's screw pumps are mainly divided into two kinds, ground driven single screw pumps and submersible motor driven screw pumps, which are currently the two major oil extraction systems in China. The former mainly uses the power of the ground to drive the sucker rod string to rotate, and eventually the rotor rotates at a low speed for live mining. The latter is mainly driven by the submersible machine in the well to directly drive the screw pump for oil extraction.
Working characteristics of screw pumps
As the main system of oil extraction in China, screw pumps have unique working characteristics and working principles. Working characteristics of the screw pump are described in three aspects such as the volumetric efficiency, stator profile and magnitude of interference.
1. Volumetric efficiency of screw pumps
The East China University of Petroleum in China has conducted a project study on mechanical mining. The test content mainly involves the influence of the two factors of medium temperature and viscosity on the working characteristics of the screw pump. Through experiments, it was found that the obvious influence of medium temperature and viscosity on the screw pump is the volumetric efficiency of the screw pump. In this study, a certain numerical simulation was carried out on the actual working characteristic curve of the screw pump, and the influence of stator rubber swelling of screw pumps on volumetric efficiency was tried to be discussed. A large number of research results show that structural optimization of the structural and working parameters of the screw pump can significantly improve equipment loss and extend the service life and working cycle of the screw pump.
Through analysis, it was also found that the actual service life of the screw pump for oil extraction often depends on the oil resistant rubber performance of the stator bushing, and the rubber stator is affected by many factors and directly affects the working characteristics of the screw pump. Nitrile rubber is used in the study at home and abroad. The modified rubber derived from nitrile rubber is also very effective in improving the service life of the screw pump.
2. The stator profile of the screw pump
On the basis of analysis and research, Yusheng Yang and others of Shengli Oilfield in China proposed a simple correction method of the stator profile to improve the accuracy of the bushing profile to improve the sealing performance. The operation is very simple. In order to fully ensure the bushing type of the stator rubber, it is believed that when the stator core is designed, the rubber should be modified according to the different formulas of the rubber, so as to enhance its stability and ensure the molding line of the rubber bush to a large extent.
With the development of technology, wireless geometry and physical linearity especially have played an important role in the detection of limitations of rubber materials. Among these methods, the finite element solution method is commonly used. Rubber has incompressible elastic material deformation. Dr. Shi in China conducted a validity study and introduced Pann invariant decomposition into rubber based on this research, which plays an important auxiliary role in enhancing the stability and convergence of the displacement solution.
3. Magnitude of interference of screw pumps
Through research, it was found that the stator lead, rotor diameter and eccentricity of the screw pump have a certain internal correlation. Only by realizing the reasonable value of each structure, can it ensure existence and effective operation of the screw pump. The main structure parameters of single screw pumps are optimized on the basis of ensuring high efficiency and long cycle working time. Through experiments, experts and scholars have concluded that magnitude of interference between the stator and rotor will greatly affect the actual work of the screw pump. Even if we can reduce the volume loss by reducing the magnitude of interference, it will also cause the increase in mechanical loss. Of course, the above analysis is only applicable to low-pressure head screw pumps, not suitable for all types of screw pumps. Now the high-pressure head screw pumps for oil extraction still need further research and analysis.
