Formulation And Application Of Demulsifiers For Breaking Crude Oil Emulsionat Low Temperature

In this paper, the development of demulsifiers for breaking crude oil emulsionat was summarized.Based on the research on demulsifiers for breaking crude oil emulsionat low temperature in the world, Inthe face of the difficulties of crude oil demulsification at low temperatures such as tight emulsion and highoil carry-over, study on 'the Formulation and application of Demulsifiers for Breaking Crude OilEmulsion at Low Temperature' was conducted. In this study, demulsifiers were characterized at lowtemperatures to screen and formulate demulsifiers that were suitable both for the demulsification of thehigh water-cut crude oil emulsion gathered and treated at low temperatures to remove the heating processesinvolved in oil gathering and treatment at production stations and to lower the oil carry-over in producedwater. The demulsifiers thus formulated played an important role in the low-temperature gathering andtreatment of crude oil which can be adopted to save a large amount of energy. The demulsifiers also helpedto increase the capacities of crude and produced water handling facilities.The study consists of 8 major parts. The starting parts cover the physical and chemical properties ofproduced liquid, emulsification of crude oil at low temperature, viscosities of crude oil emulsion of variouswater-cuts at low temperatures, oil/water separation performances at low temperatures, mechanismsinvolved in low temperature chemical demulsification and benchtop gravity settling treatment of producedliquid at low temperatures. The rheological characteristics of crude oil emulsions of various water-cuts attemperatures 3 to 5 degree Centigrade above the pour point of crude oil, composition of produced liquid,characteristics and performances of natural emulsifiers in the crude oil were presented based on the studieson the produced liquid composition, characteristics and performances of natural emulsifiers in the crudeoil, viscosities of crude oil emulsion of various water-cuts at low temperatures. Emulsification tendenciesof crude oil at low temperature were described by means of emulsion pattern, structure andcomposition of the transitional layer between oil phase and water phase, characteristics and performancesof natural emulsifiers in the crude oil, and the mechanisms of emulsification. Oil/water separationperformances at temperatures 3 to 5 degree Centigrade above the pour-point of crude oil,such as the timerequired for oil/water separation, oil/water separation performance, ratio of the transitional layers, werepresented based on the study of oil/water separation performances including determination of oil/waterseparation time, separation performances, and ratios of transitional layers. Mechanisms involved in crudeoil demulsification at low temperatures were studied by means of the determination of oil/water separationtime, separation performances, ratios of transitional layers under the effects of demulsifiers at lowtemperatures, as well as the determination of emulsion pattern, structure and composition of the transitionallayer and the interfacial properties at low temperatures in the presence of demulsifiers. The mechanismsthus presented were used as guides in the formulation of demulsifiers for low temperature demulsificationof crude oil.Establishment of the evaluation methods, formulation and field trial of demulsifiers for lowtemperature crude oil demulsification were conducted based on the studies mentioned above. A demulsifierfor low temperature crude oil demulsification, named DE1036, was formulated. Field trial showed thatDE1036 was a very good demulsifiers for low temperature crude oil demulsification and oil carry-over ofproduced water, water-cut of crude oil emulsion and water-cut of exported crude oil all met the technicallimits specified in the study proposal with a dosage of DE1036 at 15mg/l. The new demulsifier showed much better performance than the incumbent demulsifier applied at the field trial site. The demulsifierDE1036 shows a broad application as it can be adopted in such cases as high water-cut Daqing crude oil,free water knockout temperature at 34 to 37 degree Centigrade to get the separation performance of oilcarry-over of produced water below 350mg/l and water-cut of exported crude oil not more than 0.3ï¼…withstable electro-dehydrator operation. Replacing the state-of-art demulsifiers with DE1036 will not result inany cost increase as the price of demulsifier DE1036 is the same as those of the state-of-art demulsifiers.Application of DE1036 brought out an economical profit of 9.5638 million RMB due to the reduction ofthe temperature and thus cost of produced liquid and saving of energy. The new demulsifier DE 1036 is in anationally leading status as it can be applied in the oil/water separation of high water-cut produced liquid todebottleneck the low temperature dehydration of crude oil. The demulsifier DE1036 can be combined withthe low temperature oil gathering technique to enhance the application of low temperature oil gathering.Itwill experience a broad application as it contributes to the reduction of temperature and cost of crude oildehydration.