Study On The Treatment Of Oil-containing Cuttings By Acoustic-chemical Combined Method

Along with a large number oil-base drilling fluid being used in the exploition process of shale gas,which will inevitablely produce large amounts of oily cuttings.And the kind of oily cuttings are dealed improperly with,which will cause environmental pollution.How to cleanly and efficiently deal with oily sludge is a popular current research.Now common oily cuttings processing methods have land cultivation,cuttings seal,cuttings reinjection,surfactant cleaning and so on.The present more study is surfactant washing oil drilling cuttings.The surfactant processing method can be thoroughly washing oil to relative others,the cleaned drilling cuttings can be discharged safely,and low cost.But simply relying on surfactant to clean is not only low efficiency,but also the cleaned water will be caused the secondary pollution by oil drilling cuttings.Aiming at the existing problem of surfactant treatment oil drilling cuttings,which this article puts forward the ultrasonic-chemisty joint method to deal with the oily drilling cuttings.Introduction of ultrasonic wave,which use the cavitation and its side effects,such as turbulent effect,perturbation effect,gathering power effect,interface effect and so on,it can speed up oil separation,strengthen the elution emulsification,accelerate the solid liquid mass transfer,reducing the oil adhesion force to improve the cleaning efficiency of surfactant.For surfactant washing causing secondary pollution of water,this thesis puts forward synthetic pH sensitive surfactant cleaning cuttings,by adjusting the pH treatment of oily wastewater after ultrasonic elution and avoiding the secondary pollution of water.The paper first use methylacrylic acid(MAA),methyl methacrylate(MMA)and chitosan(CS)as the monomer,using emulsion polymerization to synthesize a pH sensitive surface active agent.Using FTIR,XRD,DSC,thermogravimetric analyzer and so on had been used to characterize the structure of copolymer.Changing pH of the copolymer solution aimed to study pH sensitivity of the copolymer solution,Which found the copolymer in alkaline conditions(pH ? 12),it has a very low surface tension,when the copolymer under acid condition(pH ? 4)copolymer would lost surface activity,and begin to flocculation sedimentation.This paper research the oil drilling cuttings form the Chongqing fuling region,which firstly analyze the properties of oil drilling cuttings,its oil content is 10%,and it has 90%cuttings which components are mainly composed of quartz,barite,plagioclase,no water.Making use of the ultrasonic-chemisty joint method to deal with oil drilling cuttings,which use residual oil content as evaluation indexes.This paper discusses NaOH concentration in water,solid-liquid ratio,surfactant structure and concentration,ultrasonic time,ultrasonic temperature,ultrasonic power and so on different factors to effect on the ultrasonic-chemisty joint method,acquired the optimum technological conditions:0.02g/mL NaOH concentration,solid-liquid ratio of 1:1,copolymer structure of P(MMA-MAA-CS)-3,the concentration of the copolymer is 5000mg/L,ultrasonic time for 20 min,ultrasonic temperature of 40 ?,power is 200 W,and repeated 3 times operation after oil rate from 10%to 0.93%.Drilling cuttings are treated that oil content can reach?general industrial solid waste storage and disposal site pollution control standard?(GB18599-2001)which the oil content of cuttings must be less than 1%.Processed oily wastewater can be separated of oil-water by pH adjustment:when the pH is adjusted to 4,copolymer of oily wastewater lose surface activity and begin to flocculation,which flocculation of surface active agent adsorb oil and coagulate in aqueous solution.Oily wastewater after flocculation experiment was measured the water rate is 0 mg/L,turbidity of 0 the NUT,water measurement,reach national standard emission standards.Sewage after flocculation experiment is oil content of 0 mg/L,turbidity of 0 NUT,water clear,and reachs national standard emission standards.Finally,the paper in view of the ultrasonic-chemisty joint method to deal with the oily drilling cuttings of mechanism was studied,which mainly examines the different polymer structure and concentration to the influence of oil-water interfacial tension and oil-water-drilling cuttings three-phase contact angle.It finds that the copolymer concentration is increased which interfacial tension reduces,three-phase contact angle largens(and the contact angle is greater than 90 °,non-wetting).Changing copolymer of CS,MMA and MAA monomer to oil-water interfacial tension and three-phase contact angle have affection,which more CS?MMA monomer structure can reduce the oil-water interfacial tension and largen three-phase contact angle.Combined with the experimental results of ultrasonic-chemisty joint method washing oil explain the mechanism:the surfactant solution reduces the oil-water interfacial tension which making drilling cuttings dirty oil can be quickly dissolved in the solution,ultrasonic cavitation and its side effect accelerate to strip the dirty oil on the surface of the cuttings,while elution drilling cuttings of the surface was parcelled the surfactant after the formation of oil-water-drilling cuttings three-phase contact angle is changed,wettability to non-wetting,this indication that surface active agent can prevent elution of dirty oil again adsorbing on the surface of drilling cuttings,raising the efficiency of cleaning.