Research On High Temperature Rheological Property Of Organosilicon Drilling Fluid In Daqing Oil Field

In deep well drilling, for the existence of geothermal gradient and formation pressure, the borehole temperature and pressure increases with the hole depth which causes the drilling-fluid tend to lose its original properties. In recent years, Daqing Oilfield deployed multiple deep wells and gas explorating wells in Xujiaweizi, where organosilicone drilling fluid is mostly used. This paper focuses on the rheological property of organosilicone drilling fluid at different temperatures, measured rheological parameters with HTHP rheometer and got corresponding parameter values and rheological formula in each model by the method of linear regression. The least square approach was applied to get the smallest standard deviation and optimize a rheology model that can best describe the drilling fluid property at HTHP. Mainly additives in the organosilicone drilling fluid were tested under HTHP to study their impact on the rheological property, and the influences caused by bentonite content, pH and aging time were also obtained through experiments. It was found that the non-invasion protectant BST-2 viscosified a little bit with organosilicone drilling fluid. To point against the high temperature's strong impact on the rheological property, advanced the anti high temperature protectant and the non-invasion protectant, perfected the formula of organosilicone drilling fluid and evaluated it.