Synthetic Base Drilling Fluid of Flat Rheology for Deepwater Drilling

In deep water drilling,greater changes in temperature impose higher requirements on mud rheology under low temperatures.An association polymer was synthesized as a rheological modifier to render drilling fluid stable yield point,gel strengths and φ6reading under low temperatures,and a synthetic base drilling fluid with stable low temperature rheology was developed by optimizing the concentrations of emulsifiers and organoclay,and by studying low temperature rheology of drilling fluid with different oil/water ratios and densities.The optimization and study show that compared with other synthetic drilling fluids,this flat rheology synthetic drilling fluid has stable rhological properties under wide range of temperature,and no gelation of drilling fluid is found under low temperature,ensuring safe drilling in deep water drilling.