The Effect Of Drilling Fluid's Physical Properties On The Temperature And Pressure In Deepwater Drilling

The need of Oil and Gas is increasing today, but Oil and Gas is becoming less and less. More and More marine Oil and Gas is explored and exploited, and sea depth tends to deeper and deeper. Also kinds of difficulties come up, need to be solved soon. Naturally, deepwater drilling is becoming hotter and hotter.Low temperature, high pressure, high pore pressure and low fracture pressure commonly exist in deepwater drilling and always cause accidents. We expect a new method to forecast the temperature and pressure in the wellbore. So in this thesis, we have established a model to calculate the temperature and pressure in the wellbore. We make some amelioration on the basis of others'research, including: density and rheological behavior of drilling fluid are deemed as a function of temperature and pressure; the effect of cuttings, frictional heat and pressure-drop heat are taken into consideration; what's more, the temperature and pressure in the wellbore are coupled calculated. We have made a new program according to all of these mentioned above and got more accurate results. This program can show us temperature profiles, pressure profiles, density profiles, viscosity profiles, downhole temperature and pressure curves, equivalent circulating density profiles, equivalent static density profiles in the wellbore and temperature profiles in the formation when the drilling fluid is either circulating or not, which are important for drilling, cementing, well control, casing depth design. In this paper, we also complete parametric sensitivity analysis, find the primary parameters affecting the temperature and pressure in the wellbore, give some reasonable advices.