The Development And Performance Evaluation Of Emulsifier For Oil-based Drilling Fluid With Multiple Hydrophilic Groups

Deep in kuqa piedmont tectonic of the Tarim Basin,western China,it faces the challenges of coexistence of high temperature,high pressure,huge thick salt and high pressure brine layers and is one of the most complicated areas in the world for drilling.During the drilling process,the invasion of high-pressure brine will lead to the deterioration of high-density drilling fluid,causing the resistance,card and borehole stability accidents.At present,the oil-based drilling fluid is often used in the region to ensure the safety of the underground.This requires improving the performance of the drilling fluid to meet the requirements of the site.Emulsifier as oil-based drilling fluid core treatment agent,its performance will directly affect the overall performance of oil-based drilling fluid system,the existing domestic oil-based drilling fluid emulsifier species is relatively small,it is difficult to meet the requirements of the field.Therefore,in this paper,we developed an oil-based drilling fluid emulsifier with multiple hydrophilic groups.In this paper,with increasing the number of hydrophilic groups on a single emulsifier molecular structure to improve the oil-based drilling fluid density and resistance to brine intrusion capacity limits.According to laboratory experiments,the oil-based drilling fluid system used by this kind of emulsifier,optimizing organic soil,fluid loss agent and other agents,the density of up to 2.85g/cm~3,ability to resist temperature of 200?,salt pollution resistance above 60%,and has good high temperature stability.The field application shows that the emulsifier developed in this paper has been successfully applied to the Keshen 1101 well.Domestic oil-based drilling fluid has experienced such challenges as salt water pollution in the deep well salt paste layer and high-pressure salt water contamination.Drilling fluid properties have remained stable,effectively dealt with the blocking of the deep formation,well leakage and the instability of the borehole wall.Finally,it completed the first well site construction tasks,successfully broke the monopoly of foreign technology.It is expected to Tarim Basin Kuqa Piedmont area to promote the application.