Development Of Mud Washing Water Treatment Technology In Shuguang Oily Sludge Plant Of Liaohe Oilfield

Oily sludge is a kind of oil-bearing solid waste produced in the process of oil exploitation,transportation and treatment,which contains complex components,stable properties,difficult treatment and some toxic substances as well.It has been listed in ?National list of hazardous wastes?HW08 waste mineral oil and hazardous waste containing mineral oil.Liaohe Oilfield will produce 150000 tons of sludge every year in the process of crude oil production.With the increasingly strict environmental protection policy,how to dispose these sludge efficiently and safely has become the focus of the whole company.At present,the main oily sludge treatment process in Liaohe Oilfield is chemical hot washing process,which uses hot water as carrier to prepare hydrophilic agent and oily sludge for multi-stage mixed cleaning,so that the solid phase and oil phase can be separated,and then divided into solid phase,water phase and oil phase through three-phase separation unit.The separated solid oil content is reduced to less than 2%,which can be made into bricks for resource utilization.The biggest problem of this process is that it will produce more than twice the amount of sludge.The sludge washing water contains about 2% emulsified oil and 3% fine sludge.The COD(chemical oxygen demand)content is more than 100000 ppm.Moreover,it is very stable under the action of residual agent,unable to wash mud circularly,so the subsequent treatment is difficult.At present,profile control reinjection is an unsustainable way to treat mud washing water,which not only has high reinjection cost,but also can cause well channeling and affect oil recovery efficiency.Therefore,it is necessary to develop an effective mud washing water treatment process to replace the current treatment.This paper analyzes the characteristics of the mud washing water produced by the chemical hot washing process of Shuguang oily sludge plant in Liaohe Oilfield,we figure out the formulation of the mud washing agent,analyze the mechanism of the stability of the mud washing water,and preliminarily judge that the surfactant remaining in the mud washing water changes the surface tension of the oil drop and the solid,and forms a fine and stable emulsion in the water phase under the action of the emulsifier Oil.By analyzing the factors of chemical stability of surfactant and emulsifier,the treatment idea of mud washing water is determined,which is,by introducing high valence metal cation and surfactant to react to produce salting out,which makes the surfactant inactive,and then introducing reverse demulsifier and other types of surfactant to change the stability of mud washing water system,so that the oil phase and solid can be separated from the water system.Three kinds of mud washing water treatment agents and the formula and proportion of each agent were put forward.The feasibility of mud washing water treatment agent was proved by agent screening experiment,and agent A was selected as the final treatment agent.Through a large number of experiments,the key process parameters of agent A,such as the optimal dosage,operating temperature,reaction time,solid-liquid separation centrifugal force,were optimized,and the mud washing water treatment process was developed and designed.The operation cost of the sludge washing water treatment process developed in this paper is equivalent to that of the original one.The treated water phase can be recycled for sludge washing or treated in the sewage treatment plant.The separated solid-phase oil content can be controlled below 2% for further resource utilization and the recovered oil phase can be used for resource utilization.This process solves the problem of mud washing water produced by the oil mud cleaning process from the root.The whole process is green and environmental friendly,which not only solves the current production problems,but also clears the obstacles for the oil mud treatment process of Liaohe Oilfield.