Rheological properties of fuzzy ball drilling fluidscan be met in deepwaterdrilling

Rheological properties of drilling fluid were influenced by temperature directly and then suspension property and carrying ability. The shear stress and apparent viscosity of fuzzy ball drilling fluids with density of 0.74 g/cm3, 0.80 g/cm3 and 0.84 g/cm3 were tested under different shear rate by rheological properties test machine with temperature of 10-70 ℃ and six speed rotary viscometer with temperature of 0 ℃. Rheological curve and function was fitted under different temperature. It is found yield point is large and hardly influenced by temperature. With shear rate increased and temperature decreased, the viscosity increased. It suggested fuzzy ball drilling fluids has strong suspension capacity and good properties within the change of temperature. Fuzzy ball working fluids were applied to SZ36-1 Oilfield X well, Liaohe Oilfield Y Well, Changqing Oilfield Z Well, and Fuzzy ball fluids were prepared and storage in somewhere below 20 ℃. Before injecting, the rheological properties were tested. The result was consistent with indoor test result. Therefore, fuzzy ball drilling fluids Rheological properties were applicable to deep-water working.