Research On The Flow And Heat Transfer Process Of A Heavy Oil Extractive Well

With the rapid development of industry,our demand for oil is becoming huger and huger.Gradually,the exploitation of heavy oil gradually is taken into account.Steam stimulation is the main way for extracting heavy oil.But it is seriously restricted by the loss of heat in the wellbore and the high temperature of the wellbore.The fluid's flow and heat transfer mechanisms in the wellbore were researched,during the steam injection stage,soak stage and oil recovery stage of the steam-swept production process;established a flow and heat transfer non-steady-state coupled model;using C#software compiled the simulation program composition.The model can accurately predict the unsteady state law of temperature,dryness and pressure of the fluid in the wellbore and the unsteady state law of wellbore temperature.The model was verified by the field measured data.The absolute error between the calculated and the measured value of the steam dryness in the wellbore is less than ? 5%,? 5% for the steam temperature,? 10% for the oil output,? 5%for the bottom casing temperature.Using the model can research the unsteady state law of steam parameters,wellbore temperature and oil production of a thermal well.In the subsequent study change the steam injection conditions,such as steam injection flow,pressure,and dryness,then research the unsteady state law of steam parameters,wellbore temperature and oil production of a thermal well.The calculation results show that the steam dryness reach a steady state about one hour after the beginning of the steam injection,ten hours for the steam temperature.Both the intial steam injection stage and the intial soak stage,the wellbore temperature rises rapidly.Meanwhile increasing the injection flow rate and dryness,and reducing the steam injection pressure are beneficial to increase oil recovery rate and to reduce wellbore temperature.The research can provide scientific reference for optimizing the steam stimulation process and reducing the wellbore damage.