Study On Fluid Flow Froperties In A Pump Under Low Submergence Condition

The ultra-low permeability tight reservoir has the characteristics of small porosity,low permeability and poor oil supply capacity of the oil layer,which makes the oil pump have a low degree of submergence for a long time,which seriously affects the pumping efficiency of the pump and the liquid production of the oil well.In this thesis,the sinking degree and working state of the pump in a certain oilfield in the Ordos Basin are investigated and analyzed.And the structure and working principle of the tubular pump used in the low-sink condition and the characteristics of oil pump worked under this condition are introduced.The gap flow between the plunger and cylinder and the valve clearance flow of the fluid under the low-sink condition are theoretically studied.And the flow at the inlet and outlet of the pump,the pressure on the ball and the fluid loss in the gap are simulated based on the AMEsim software on the conditions of different stroke,and different submergence depth,different discharge pressure and gas liquid ratio and the pump under different gap width at the entrance of the flow.At the same time,the test is verified.The conclusion is as follows: the leakage of the pressure difference between the plunger and the pump barrel occurs in the upper stroke;the stroke is increased,and the pumping volume of the pump is increased: the pumping stroke is increased,the fluid flow at the inlet and outlet of the pump is increased,and the gap loss is increased;when the degree of sinking is increased,the pressure fluctuation range on the valve ball is reduced,and the leakage loss is reduced;the outlet pressure is increased,the flow rate at the pump inlet is increased,and the pressure fluctuation range acting on the ball valve is decreased,the leakage loss is reduced;the gas-liquid ratio is increased,the pressure acting on the valve ball is reduced,the pump inlet flow is reduced,the gap leakage is reduced;the gap between the plunger and the pump barrel is increased,and the inlet flow of the pump is reduced,the amount of gap leakage is increased.