Offshore Directional Well Jet Pump Lifting Heavy Oil Process Design

Jet pump production system is a very important artificial lift technique. Because it has advantages that have no moving part in down hole and output range is varied, compared with sucker rod pump, it is more fit for offshore deviated well and directional well, used the heated water that produced from layer as it's power fluid in heavy oil production, This method is very significant for our country's heavy oil exploitation.It is the basis of the nodal system analysis to predict accurately the profile of the flow pressure, temperature of the fluid in the wellbore. The mathematic model is established based on mass, momentum, energy conservation and the theory of wellbore radius heat transmission. The model allows for the Joule-Thomson effect, the structure of the well, the structure of oil string, different heat transfer medium in annular and changes of the heat physical properties of the formation with the depth. According to the changes of deviation angle calculated the pressure distribution of directional well.The Inflow performance of directional well and deviational well is more complex than vertical well and according to the conditions choose the calculating method. In the flow of heavy oil, pressure decline principal behave as friction loss. So the gradient of pressure decline in vertical well section and deviated well section is different, it aroused the gradient of fluid viscosity in the two sections has differentia.This paper presents that the jet pump can be considered as a functional nodal. Adopted the analysis method of temperature balance point, iterate calculated the temperature distribution on the precondition which the wellhead temperature is unknown. Because of the differentia of transmission heat media and temperature different between power fluid and produced fluid, so the temperature distribution is nonlinear. The depth of balance point is changed by injection fluid temperature and led to the viscosity changed.Making allowance for cavitation, On condition that initial output and pump setting depth, aim for the maximum of jet pump, calculate the all combination of nozzle and throat, chosen the best one group. Inject the heated water that produced from layer from annular for heat the heavy oil. It can reduce the liquid viscosity efficient, increase it's fluidity and it is a effective method for heavy oil reservoir. The depth of heated well is changed by injected temperature.