绒囊钻井流体在深水油气井中应用的可行性

研究不受温度影响的钻井流体对于深水油气田安全高效钻井具有重要意义。室内采用流变性测量仪10~70℃、六速黏度计0℃,测定密度分别为0.74 g/cm3、0.80 g/cm3和0.84 g/cm3绒囊钻井流体在不同剪切速率下的剪切应力或黏度,然后拟合绒囊钻井流体在不同温度下的流变曲线和方程,发现绒囊钻井流体动切力较大,且随温度变化不大,因而悬浮能力较强;绒囊钻井流体的黏度随剪切速率的增大而增大,随温度的降低而小幅增大,表明绒囊钻井流体在研究温度范围内变化时能够保持良好性能。绒囊流体低温下应用于SZ36-1油田X井修井、辽河油田Y井堵水、长庆气田陕Z井修井,在–20℃环境中配制存放,注入井筒前测量结果和室内实验结果一致,且施工顺利。因此,绒囊钻井流体流变性满足深水作业需求。

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.