The Research and Application of a Fine MPD Flow Model

In order to improve the calculation accuracy of annulus pressure profile and realize fine calculation of bottomhole pressure,a fine MPD flow model was established for high temperature deep wells based on comprehensive research methods including hydraulics,heat transfer theory,rheological basic theory,viscosity-temperature characteristics,lab experiment,comparison with Drillbench software,verification by measured downhole annular pressure,etc.Factors such as annulus temperature distribution,drilling fluid viscosity-temperature characteristics,drilling fluid density characteristic under high temperature and high pressure were fully considered.This model realized the coupling calculation of pressure and temperature.Field application showed the accuracy of this model was higher than that of other models,with an absolute error of merely about 0.2 MPa.The model provided a better means of pressure calculation and annulus pressure control for pressure sensitive reservoirs in high temperature deep wells.