基于乳状液转相技术的钻井液新体系室内研究

为有效解决油基钻井液应用中存在的固井质量较差、环境污染严重等问题,采用有机胺质子化可逆原理,赋予油基钻井液以乳化相态的可逆性,研制了一套可逆乳化钻井液体系。该钻井液体系的配方为5#白油+25.0%CaCl2溶液+1.0%有机土+0.5%石灰+1.0%润湿剂RS+4.0%乳化剂ET,油水比为50:50,密度为1.2 kg/L。通过室内试验对该钻井液体系进行了全面的性能评价,结果表明,通过酸触相反转和碱触相回转,可实现W/O型与O/W型间自由转换;且转换前后的钻井液性能良好:破乳电压达500~900 V,抗温达180 ℃,高温高压滤失量小于15 mL,流变性与传统逆乳化钻井液相当,可抗10%硫酸钙、20%钻屑污染,渗透率恢复率和滚动回收率都达90%以上,泥饼和含油钻屑更易处理。这说明,研制的可逆乳化钻井液体系兼备油基钻井液和水基钻井液的优点,且各项性能均为优良,能解决常规油基钻井液应用中存在的问题。 

Laboratory Study of a Novel Drilling Fluid Based on Emulsion Phase Diversion Technology

A novel reversible emulsion drilling fluid which is useful in resolving the contradiction between drilling efficiency,cementing and environmental effect has been invented based on the protonation reversibility of amine.The new drilling fluid system has reversible emulsion-phase behavior.The formulation of the reversible emulsion drilling fluid was:5# white oil+25.0% CaCl2 brine+1.0% organoclay+0.5% lime+4.0% reversible emulsifier ET+1.0% wetting agent RS,oleaginous fluid to non-oleaginous fluid-ratio was 50/50,drilling fluid density was 1.2 kg/L.Comprehensive performance evaluation with laboratory test showed that the new drilling fluid could be readily and reversibly converted from a water-in-oil emulsion to an oil-in-water emulsion and back to a water-in-oil emulsion using an acid-base chemical switch.And before and after converting the emulsion mud maintains good performance,with emulsion-breaking voltage of 500-900 V,resistance to high temperature of 180 ℃,HTHP filter loss of less than 15 mL,rheology comparable with traditional invert emulsion drilling fluid,and resistance to 10% calcium sulfate and 20% cuttings pollution.Additionally,both permeability recovery value and rolling recovery ratio were above 90%,and the filter cake and oily cuttings could be treated easily.This suggests that the reversible invert emulsion drilling fluid has both merits of oil-based fluid and water-based fluid,and all properties are excellent.The reversible invert emulsion drilling fluid is capable of resolving the problems with the application of conventional oil-based drilling fluid.