基于深水钻井的新型矿物油基钻井液性能研究

Laboratory Research on Properties of New Mineral Oil Drilling Fluid for Deep-water Drilling

油包水型钻井液体系在深水钻井中应用比较广泛,钻井液的低温流动性和抑制气体水合物生成是深水钻井液中比较受关注的问题。研制出一种新型矿物油钻井液,通过测定其在不同组成时的粘温特性,研究了基础油、乳化剂种类、有机土加量、油水比以及钻井液固相含量等对油包水钻井液低温流动性影响,探讨了低粘矿物油钻井液对气体水合物生成的抑制性。试验结果表明,基础油的低温粘度是影响油包水钻井液低温流动性的关键因素,其次是乳化剂种类、有机土加量和油水比,而惰性固相加重材料对油包水钻井液低温增稠作用影响较小。在此基础上,优选出低粘矿物油钻井液配方:70%低粘矿物油+30%盐水+2%有机土+3%乳化剂+0.5%润湿剂+3%降滤失剂+2%石灰,该钻井液具有较好的低温流动性,性能稳定,能有效抑制气体水合物生成,可以应用于深水钻井作业。

Water-in-oil drilling fluid system was widely used in deep-water drillings.Meanwhile,rheological property of the drilling fluid and gas hydrate inhibition were the major problems in deep-water drilling,which was widely concerned.A new mineral oil drilling fluid was developed,the factors such as base oil,emulsifier kinds,organic clay dosage,oil-water ratio,and solid content,which effect low temperature flowability of water-in-oil drilling fluid were researched by testing viscosity-temperature properties of drilling fluid.Finally,gas hydrate inhibition of low viscosity mineral oil drilling fluid was studied.The results show that base oil viscosity,emulsifier kind,organic clay dosage and oil-water ratio are influencing factors of flowability of the fluid in low temperature condition,in which,base oil viscosity is decisive factor.While,influence of inactive weighting material content on thickening extent of drilling fluid in deep water drilling condition is limited.Based on these results,an optimized formula of low viscosity mineral oil drilling fluid is obtained,it includes 70%low viscosity mineral oil+30%brine+2%organic clay +3% emulsifier+0.5%wetting agent+3%filtrate loss reducer +2% lime.This drilling fluid has excellent flowability in low temperature condition,it has a stable property and good gas hydrate inhibition,it is suitable for deepwater drilling.