Evaluation and Application of the High Performance Environmentally Friendly Drilling Fluid Lubricant HPRH

With drilling geological conditions becoming increasingly rigorous, high drag and torque encountered in long horizontal drilling and high temperature deep well drilling have imposed higher requirements on the lubricity, thermal stability and toxicity of lubricants. These requirements are apparently not be able to be satisfied with lubricants presently in use. Laboratory experiments have been conducted in the selection of base oil, optimization of lubricity enhancers and optimization of conditions for the development of a high performance environmentally friendly lubricant, HPRH. In laboratory evaluation test, 0.5% (mass ratio) HPRH in fresh water base drilling fluid reduced the friction coefficient of mud by 93.75%, while in 4% NaCl saltwater base drilling fluid, this percentage reduction in friction coefficient was more than 80%. HPRH functions properly at 160℃, has low foaming and is free of fluorescence. Laboratory pin-disc friction and wear test results show that HPRH has remarkable anti-wear and wear-resisting property, and good lubricity persistence. After being wore for 60 min, the volumetric abraded quantity of the disc was only 6.92×10^-13 mm³/(N·m). Field application of HPRH on two appraisal wells drilled in Block LN in Tarim Basin showed that, compared with compound lubricants used in field operations, HPRH has better lubricity persistence, and the amount of HPRH was reduced by at least 50%. The use of HPRH effectively avoided downhole troubles such as being unable to exert pressure on bit and pipe sticking etc., greatly reducing the drilling cost and enhancing the operational efficiency.