Analysis And Research On Temperature And Pressure Field For Marine MPD

MPD is an effective way to solve the problem of narrow density window,but currently the theoretical analysis and calculation methods for marine drilling systems of MPD are still at the beginning in the domestic.Different from land drilling,the wellbore segment below the mud line have a very inconsistent temperature with riser section above the mud line in offshore drilling.The temperature difference will cause changes in the density of the drilling fluid,and influence the pressure control in further,so it is necessary to describe the temperature field of the wellboreThis paper discussed the existing marine MPD technology in detail,analyzed the principle of pressure control for marine MPD,and generally introduced all pressure control process under different working conditions.Two temperature models were established during the stop cycle and cycle to calculate the marine wellbore temperature field below the mud line segment and the riser section.This calculation method of temperature field simplify the solution process to realize the engineering apply.Accurate calculation of annual pressure consumption is another important issue to marine MPD.The optimization of rheological model for annual space fluid is a basis to hydraulic calculation,the paper will involve the specific steps to implement the optimation.After selecting the rheological model,the judgment of flow pattern is needed.In this paper,the calculation method of annual pressure loss is analyzed among laminar flow and turbulent flow.Moreover,to ensure the pressure loss calculations are more in line with actual engineering,the pressure for local consumption due to drill pipe joint and dynamic drilling tool are classified and discussed.Example analysis of annular pressure loss further shows that the increase of the well structure will increase the annular pressure loss,and the value of annular pressure is gradually increased with the increase of depth.