Preperation Of Environmental Drilling Fluid Using Fruit Peel

As an increasing need for the environment protection, developing the safe, environmental friendly and high-efficiency drilling fluids and technology become more and more important. Natural materials have drawn much attention of oilfield chemists. Lignin, tannins, starch, cellulose and plant gum, are important environmental friendly oilfield chemical materials. In the paper, natural polyphenols-glycans complex, fruit peel, was developed as environmental friendly drilling fluid additives, forthermore the process and application technology was studied.In this paper, four kinds of fruit peels, including shaddock peel, orange peel, walnut green peel and persimmon peel, were dried and powdered at first. Inhibition to clay hydration of the water extracts of fruit peel and thermal resistances of the fruit peel treated drilling fluids were evaluated. The application technology is initially explored in common drilling fluid system(modified starch, PAM, heteropolyglycoside). The results show:(1) the four fruit peel water extracts have effective inhibition to clay hydration;(2) as the increase of aging temperature, shaddock peel(orange peel/persimmon peel) can enhance viscosity, ruduce FL and resist 170℃(140℃/150℃) in fruit peel treated drilling fluid, and walnut green peel can increase viscosity first and then decrease it, ruduce FL and imprve the temperature resistance to 160℃;(3) in modified starch drilling fluid, the four fruit peels enhance the performance of the drilling fluid and enhance the high-temperature resistance; in PAM drilling fluid, both shaddock peel and orange peel show synergistic flocculation with PAM, walnut green peel(or persimmon peel) enhance viscosity and ruduce FL; in heteropolyglycoside drilling fluid, the four fruit peel enhance viscosity and ruduce FL at low-temperature, and shaddock peel ruduce FL and walnut green peel/persimmon peel enhance viscosity at high-temperature, but orange peel is ineffective.The shaddock peel and orange peel were modified by cross-linking reaction, and the conditions were optimized by the orthogonal designed experiments, range analysis and single-factor experiment. Inhibition to clay hydration of the modified fruit peel products is evaluated, and the application technology is initially explored in common drilling fluid systerm. The results show:(1) the viscosity and the inhibition of modified shaddock peel water-soluble glue to clay hydration is obviously increased, the thermal resistance of modified shaddock + modified starch drilling fluid is enhanced to 150℃, synergistic flocculation with PAM is weakened, and property of suspension and carrying of heteropolyglycoside drilling fluid is improved;(2) the viscosity and the inhibition of modified orange peel water-soluble glue solution to clay hydration is obviously increased, the thermal resistance of modified starch drilling fluid is improved, and synergistic flocculation with PAM is weakened.Furthermore, the production technology of fruit peel drilling fluid additives is explored initially. This will provide basic reference to develop the new environmental drilling fluid additive.