深水低温条件下油基钻井液流变性能实验研究

Experimental study on rheological property of oil-based drilling fluid under deep water and low temperature conditions

深水钻井过程中,海水低温环境对油基钻井液的流变性能有较大影响。文中采用Haake RS300流变仪测试了油基钻井液低温下的流变性能,并研究了基础油种类、提切剂、有机土和加重剂加量对钻井液低温流变性能的影响。结果表明,Haake RS300流变仪能精确描述油基钻井液低温下的流变性能,特别是低剪切速率下的流变性能;低温条件下,油基钻井液的剪切应力随剪切速率的变化呈现2个阶段(极低剪切速率下的线性阶段和中、高剪切速率下的剪切稀释阶段);基础油种类、提切剂、有机土和加重剂加量对油基钻井液低温下的流变性能影响显著,特别是低剪切速率条件下的流变性能。

Low temperature environment has a great impact on the rheological properties of oil-based drilling fluid in the process of deepwater drilling. Haake RS300 rheometer can be used to test the rheological properties of oil-based drilling fluids and the influence of base oil type. modifier agents, organic clay and solid content on rheologieal properties of drilling fluid at low temperature. The results show that Haake RS300 rheometer carl accurately describe the rheological properties, especially the rheologieal properties of oil-based drilling fluid at low temperature and low shear rate. The change of shear stress with shear rate curve of oil-base drilling fluid presents two stages under low temperature condition, they are the linear stage at very low shear rate and the shear thinning stage at middle rate and high shear rate. Base oil type, modifier agent, organie clay and solid content significantly affect tire rheological properties of oil-based drilling fluids under low temperatures, especially low shear rate condition.