Design of Simulated Test Device of Gas - Liquid Two Phase Flow Hydraulic Pump

Studying the pump flow field, especially the mixed-phase flow field, is the key to improving the pump performance. For this purpose, the University of Petroleum (Beijing) developed a set of simulation test devices for a gas-liquid two-phase flow hydraulic pump. The device consists of a single-phase flow test device and a mixed-phase flow test device. The former can simulate various working conditions in the downhole well and flow state of liquid in the oil pump more accurately, the latter can simulate different oil-gas ratio. In order to quantitatively complete the transient measurement of the flow field without disturbing the flow field, the image processing results of the velocity vector and the curl field of the planar flow field are given to reveal the transient flow structure of the flow field. , Spatial resolution and fast dynamic response characteristics of particle imaging speed (PIV) advanced technology. Oil pump is one of the main equipment in the process of oilfield development. Improving the performance of oil pump can effectively increase the output of crude oil in the oilfield and improve the economic benefits of oilfield development. At present, the development of the pump can be divided into the following three aspects. (1) Based on the mechanics analysis, through the simplification of the movement conditions and the stress conditions, the mechanical valve opening and falling process is described mechanically; (2) Based on the principle of functional design according to the production needs, the technical innovation is made on the basis of the original pump structure , Such as the development of anti-sanding card pump and anti-gas pumping heavy oil pump; (3) The related testing and observational studies in the laboratory are carried out for the purpose of studying the efficiency of pumping oil pump and its influencing factors. Such as Daqing Petroleum Institute pump energy consumption test research, the use of pressure sensors and displacement sensors to measure the pump import and export pressure curve, the pressure drop curve of the ball valve and the dynamometer, leakage and so on. At the moment, the most fundamental problem with pump performance improvements - the pump flow field - is not covered yet. The key factor to solve the problem of pump valve's movement, reasonability of pump structure and its improvement is the flow field in the pump. Therefore, studying the flow field in the pump, especially the mixed-phase flow field, is the key point to improve the performance of the pump . With PIV (particle image velocimetry) technology, LDV (Laser Doppler Flow Velocimetry) technology and ultrasound technology are maturing, one can use these advanced flow field test techniques to reach the assay without disturbing the flow field High-precision, there are already examples of the use of these advanced technologies in Canada to study the pump flow field, but no published results were found. Therefore, the use of PIV and other advanced technology to study the flow field within the pump to improve the structure of the pump is the general direction of development in the future. In view of this, the University of Petroleum (Beijing) Offshore Engineering Laboratory carried out a visualization of the internal flow field in the pump. Since there is no precedent in this respect, it is planned to proceed with the experiment first and put both theory and practice together. Pump simulation test device design ideas Pump in the downhole working medium is not single-phase, so on-site pumping pump cavity flow field actual test more difficult. In order to save time and money, but also to test the flow field of pump cavity under normal circumstances, the pump simulation test device must have gas source and liquid source, as well as visualization of research conditions, and the flow rate can also be single Liquid and gas-liquid two-phase flow characteristics of the pump when the visual observation and recording, so the entire pump chamber should be transparent. In addition, due to the strong variation of the flow field, there should be a corresponding data acquisition and processing system. In order to observe the effect of pump stroke on the flow field, the rod drive system should be adjustable. The structure of the simulation test device is designed to simulate the vertical reciprocating motion of the plunger and polished rod of the on-site oil pump, and the proper power system must be selected. One solution is to reduce the on-site pumping system of ground power, that is, take the motor-driven donkey head drive. The disadvantage of this solution is the high cost, large area, not suitable for laboratory use. Another solution is to use the motor to drive the rope directly through the pulley rod and plunger up and down movement, but in order to ensure the balance of the system to be configured balance weight, the other selection of micro-motor has difficulty. These two programs are unable to simulate the import and export pressure pump, pump flow can not be adjusted. To solve the above problems, I used hydraulic control system and pneumatic control system to achieve dynamic system simulation. Hydraulic control system is mainly to achieve reciprocating plunger up and down and control the pressure of import and export, pneumatic control system is to control the mixed-phase flow of intake. At the same time, the hydraulic control system is divided into two parts: the first part is the power cylinder hydraulic system, which is the main power source; the second most is the pump pressure compensation system, mainly used to control the pump import and export pressure And for the pump oil. Here are the three parts to be introduced. 1. Power cylinder hydraulic system Power cylinder hydraulic system mainly by the power cylinder, travel switch, two four-way solenoid valve, relief valve, pump and governor valve composition. 1-power cylinder; 2-position four-way solenoid valve; 3-speed valve; 4-relief valve; 5- 5-7; stroke switch works: When the power oil pump to the upper end of the fuel tank When the light rod touches the travel switch 6, the two-position four-way electromagnetic reversing valve commutates, the power oil pump starts to supply oil to the lower end of the power cylinder, and drives the piston to move upwards, so as to drive the light rod downward. Drive the polished rod to move upwards; when the polished rod touches the limit switch 7, the two-position and four-way electromagnetic reversing valve will change direction again to restart the next stroke. Speed ​​control valve piston speed can be adjusted to change the stroke, the relief valve can adjust the pressure inside the power cylinder, changing the plunger drive. 2. Suction pump pressure compensation system Suction pump pressure compensation system mainly consists of fuel tank, pump, sequence valve, accumulator, pump, pressure gauge, pressure tank and relief valve. 1 oil tank 2 oil pump 3 sequence valve 4 accumulator 5 oil pumping pump 6 pressure gauge 7 pressure oil tank 8 accumulator 9 relief valve Working principle Oil pump always In working condition, the relief valve is adjusted to a certain pressure, when the pump inlet and outlet pressure exceeds the regulation pressure, the relief valve overflow, the inlet pressure decreases; when the inlet pressure is too low, the pump oil pressure tank, so that the import Pressure rises to regulate pressure. The role of two accumulators is to avoid the import and export pump pressure fluctuations, to ensure that the import and export pump pressure to meet operating conditions. 3. Pneumatic Control System Pneumatic control system consists of air pump, gas flow meter, electromagnetic switch, check valve and travel switch. 1-gas pump; 2-gas flowmeter; 3-electromagnetic switch; 4-way valve; 5 5- pump; 6-stroke switch works: When the pump to do the stroke of the campaign, the electromagnetic switch is turned on, Valve into the pump, when the polished rod contact with the upper limit switch, the electromagnetic switch is closed, the gas barrier, when the pump down stroke to do sports. When the polished rod touches the down stroke switch again, the electromagnetic switch is opened and the gas path is opened, and the gas is supplied to the oil pump again. The characteristics of the simulation test device The simulation test device is divided into two parts: the first part of the single-phase flow test device, mainly by the power cylinder, plexiglass pump cylinder and plunger, hydraulic control system, is the pump simulation test device The most prominent feature of the core part is that it utilizes the hydraulic control system to drive the plunger to reciprocate up and down. It has the characteristics of stable travel, rapid commutation and complete simulation of downhole conditions. It can simulate various underground working conditions and pumping Fluid flow in the pump. The second most are mixed-phase flow test device, mainly by the pump, gas flow meter, electromagnetic switch and water tank. The characteristics of this multiphase flow device are simple and easy to use, relatively perfect function, can simulate different oil-gas ratio, and the intake air is completely controlled by the electromagnetic switch driven by the travel switch, which can more accurately simulate various working conditions in the well. In addition, in order to facilitate observation and testing, plunger and pump cylinder made of plexiglass, so as to achieve the purpose of using this test device to observe and test the pump flow field. The test device is finally selected through the optimization and demonstration of different schemes. The structure is light, the function is complete, the control system is simple and reliable, and the operation is convenient. The test device can well simulate the operation of the pump and the various working conditions in the pump. This test device is an innovative simulation of the pump test device, compared with similar simulation devices at home and abroad, both in terms of cost or overall performance has its own unique characteristics. The image acquisition and processing system can quantitatively measure the transient state of the flow field without interfering with the flow field and can give the velocity vector and the curl field of the planar flow field to reveal the transient flow structure of the flow field Image processing results, using particle imaging velocity (PIV) technology. Particle imaging velocimetry has the characteristics of high precision, high spatial resolution and fast dynamic response. It is the most advanced technique for measuring complex flow fields. It can freeze the flow field at some point, revealing the hidden turbulent flow structure. The measurement results are of sufficient precision to subtract the large average velocity from a vector and thus give flow parameters that fully reflect the flow field, such as average velocity, pulsation velocity, and vortex, respectively Test technology does not have. Generally speaking, a complete PIV system can be divided into three major parts: the first is the lighting system whose function is to generate the light source; the second is the recording system whose function is to generate a double (multiple) exposure image of the particle flow; Third, the query system, its function is to extract and display the image of the velocity field and other flow parameters. The lighting system in the simulation experiment device uses a 10W neon laser, the recording system uses a video recorder, and the inquiry system uses the PIV image processing software developed by the University of Petroleum (Beijing).