Research On Oil Based Drilling Fluid With High Temperature Resistance

Compared to water based drilling fluid, the oil based drilling fluid has the competence of wellbore inhibition and stabilization, and it provides protection for formation, especially for water-sensitive formation. Meanwhile, the oil based drilling fluid has great capability of high temperature resistence and lubricity, which can be widely applied in deep well and high-angle deviated well. Given the development of oil based drilling fluid and the synthese knowledge in organic chemistry, the synthese of w/o emulsifier with high temperature stability has been conducted, and the optimized process condition is finally obtained through the orthogonal test and single-factor analysis.The product called EMUL-1 is viscous black fluid. The laboratory experiment manifests that this product has great property of emulsification (2% dosage of the product is very effective), high temperature stability, salt resistance and reinforcement for oil based drilling fluid.Based on the synthesized emulsifier, organic clay, filtrate reducer and wetting-reversal agent are optimized and oil based drilling fluid then is formulized. The property of such drilling fluid system can still be stable at 220 degree celsius. The drilling fluid can also resist water and salt incursion. Thereafter, the field experiment of oil based drilling fluid is carried out. The field experiment demonstrates that the oil based drilling fluid has the edge on high temperature stability, wellbore stabilization, drilling rate enhancement and formation protection. In the meantime, the oil based drilling fluid successfully resolves the problem of hole shrinkage, expansion, collapse and sticking of the tools in troublesome zone drilling.