Calculation Method Of Gas-Water Two Phase Flow In The Gas Reservoir Of Ultra-High Temperature And Pressure

Bottom hole pressure is one of the most important parameters what affect well productivity evaluation & the production systems and production optimization of dynamic analysis in gas production.For ultra-high temperature and pressure gas reservoir,it’s diffcult to obtain bottom hole pressure by directly test,therefore bottom hole pressure is calculated commonly by the wellhead pressure.The calculation of bottom hole pressure in ultra-high temperature and pressure gas reservoir exists the following problems:It’s unapplicable for conventional method to calculate accurately gas property parameters in the condition of high temperature and pressure;For the interaction of temperature and pressure in the gas wellbore,it can’t to accurately predict the distribution of pressure and temperature in the wellbore by conventional calculation of temperature and pressure separation;For the hign GWR and the complex of two-phase flow,it’s difficult to select multiphase pipe flow pressure drop of conventional computation model to calculate pressure.To solve the problem, the paper based on the well site data and experimental data in the Sichuan Basin belt Tongnanba Heba Heba field 1 well,Fluid property parameters calculation of conventional methods in ultra-high temperature and pressure gas reservoir is studied, The correction method of calculating Z-factor in the ultra-high temperature and pressure condition is Posposed;The paper apply wellbore fluid mechanics and heat transfer theory to establish ultra-high temperature and pressure gas-water two-phase model of temperature-pressure coupling;Evaluating and Selecting the actual data used for different GWR multiphase pipe calculation model.According to the study achieved the following:1. The correction method of calculating Z-factor in the ultra-high temperature and pressure condition is Posposed, which based on temperature and pressure correction factor to Corrected HY method;2. The model of Gas-water two phase flow temperature-pressure coupling in the condition of ultra-high temperature and pressure is established.Applying wellbore conservation of energy, conservation of mass,momentum of conservation and heat balance between wellbore and formation to establish coupling model and fourth order Runge-Kutta method is used to slove the model;3. The calculation method of basic parameters required to calculate wellbore temperature is studied;4. Different GWR for gas-water twp phase flow pressure model is evaluated and optimized; Oden Corrected Cullender-Smith model,Hagedorn-Brown model, SWPI-SPA model in the case of hign GWR are applicable in the condition of GWR 3000 m3/m3;SWPI-SPA model is more applicable than the other model in the 1000-3000 m3/m3 GWR,Duns-Ros model,Beggs-Brill model can meet the situation of GWR less than 1000 m3/m3 wellbore pressure calculation.5. The sofeware of High Pressure Gas Reservoir Gas-Water Two Phase Flow Calculation is programmed.It’s proved that the model is applictiale by the results of calculating the Heba 1 well production data.