Technical Study On Gudong No.4 Combined Station Produced Fluid Dehydration By Chemical Demulsification

With the continuous exploitation of reservoir,part of China's oil field has entered the high water cut stage,the difficulty of exploitation is increasing.Enhanced oil recovery technology has improved oil recovery,at the same time,it changed the properties of produced fluid which made the dehydration of crude oil emulsion different.Therefore,polymer produced fluid demulsification study has important significance for practical production.Thermal recovery of heavy oil and polymer flood of crude oil production accounted for 3/4 of the total output of Gudong oil production plant.Compared with the conventional polymer flooding produced liquid,the produced fluid composition of Gudong oil production plant is more complex,the degree of emulsification of oil and water is particularly serious,and dehydration is very difficult.With the analysis of physical properties of the produced fluid from Gudong,combining with the site condition of dehydration,to determine the optimum conditions for laboratory emulsion preparation: the temperature of emulsification is 65 ?,emulsifying machine stir intermittently,emulsion strength is 800r/min of the emulsification machine speed,stirring and emulsifying 10 min,add the aqueous phase gradually and slowly after preheating.Simulate the settling and dewatering process of Gudong produced fluid by bottle test,the results show that the oil soluble demulsifier demulsification effect is better than the water soluble demulsifier,and finally choose the BC-018 L.Appraise the evaluation of oil soluble demulsifier BC-018 L in experimental condition.Dehydration temperature of 70 ?,demulsifier dosage 70 ppm,pre dehydrant amount 15 ppm,and 10 hours setting time can make the moisture content of residual oil achieve the processing requirements.At the later period of settlement process,the dehydration rate has slightly increasing trend with the extension of time.With the change of demulsifier concentration,the dehydration rate changes obviously.Because the dehydration conditions of combined station is much more complicated than the conditions in laboratory,so the recommended dosage is BC-018 L 80ppm,pre dehydrant 15 ppm.Based on determining the demulsifier and the best dehydration conditions,with the analysis of simulation,optimize and improve the dehydration process of Gudong No.4 combined station.The experiment found that addition method of demulsifier is a great impact on the effect of dehydration.Ultimately determined the optimal dosing method of adding demulsifier is punching in branch pipe,and the method of punching is to punch in the both sides of the branch pipe along the radial direction of the main pipe.In addition,the use of SK type static mixer in combination with SX type static mixer can enhance the mixing effect,and finally make crude Gudong No.4 combined station's oil moisture content below 15%.