极地冰层取心钻进超低温钻井液理论与试验研究

Theoretical and Experimental Research on the Ultra-low Temperature Drilling Fluids for the Polar Ice Coring Drilling

南极冰层取心钻进的关键之一是钻井液的耐温能力。根据南极冰层钻进的特点及对钻井液的特殊要求,在综合分析国内外冰层钻进钻井液应用经验的基础上,对有机硅、氟代烃、一元脂肪酸酯及二元脂肪酸酯进行了理论上的分析研究,测试了各自在不同温度条件下的粘度和密度,分析了粘度与密度变化的机理。确定出分子间相互作用中无氢键形成的物质的粘温系数最小,脂肪酸酯的粘温系数受到分子间氢键的数量影响最大,指出了介质密度的增加是由于体积收缩所致,与介质的分子结构与形态无关。所得到的结论对于极地冰层取心钻进钻井液的选择与确定具有重要的理论与实际意义。

The low temperature resistance of drilling fluid is one of the keys for core drilling in Antarctica ice sheet. Ac- cording to the characteristics of ice core drilling and the special requirements for drilling fluids in Antarctic, based on the comprehensive analysis on the application experience of ice drilling fluids both in China and abroad, theoretical study was made on organosilieon, fluohydrocarbon, aliphatic monocarboxylic acid ester and aliphatic dibasic acid ester, their viscosity and density were tested under different temperatures and the mechanism of changes in viscosity and density were also ana- lyzed. The result indicates that the hydrogen bond strongly influences the viscosity temperature coefficient of the fatty acid ester, and the lowest viscosity temperature coefficient of drilling fluid could be obtained if there is no hydrogen bond forma- tion. Besides, the increase of the density mainly depends on the shrinking volume of the drilling fluid; the chemical struc- ture and morphology have nothing to do with the change of density. These results have theoretical and practical significance for the selection and optimization of the ultra-low temperature drilling fluid system for ice core drilling in Polar Regions.