Study On Treatment Technology Of Acidification Reagent Solution In Oil Well

Acidizing technique of immovable string is usually used in acid treatment on offshore oilfields. Despite this acidizing technique can simplify construction technology, cut the cost, reduce the cycle-time and overcome the effect of shipping date and weather, as the acidification back-flow liquid flowing from shaft to production process, it can corrode the whole production facility, make the electric dehydrator tripping, let the rate of water in the electric oil out of standard. Aim at this situation, the treatment is that we store the acidification back-flow liquid by using buffer tank and transport to the land. The treatment not only waste time and money, but also restrict the application of acidizing technique of immovable string on offshore oilfields. The treated object of this thesis is acidification back-flow liquid from JZ9-3oilfield and SZ36-1oilfield. Firstly, the thesis will have a research on water quality analysis and treatment methods study in lab. Then the process parameters in lab can help the cooperative engineer designs treatment system of acidification back-flow liquid. Finally, this treatment system will normally work on the offshore platform.In the lab, the acidification back-flow liquid divides into water phase acidification back-flow liquid and oil phase acidification back-flow liquid which is circumscribed by2%oil in water. The thesis does research on acidification back-flow liquid separately because the two parts have difference in components and the mechanization on crude oil dehydration. For the water phase acidification back-flow liquid, firstly, it is succeed in adjusting pH to6.5-8.5by using the20%Na2CO3liquid, then the water phase acidification back-flow liquid is treated to the recycle water quality standard (iron ions content≦10mg/L, solid content≦100mg/L) by adding oxidizer NaClO which concentration is between100to400mg/L and anionic flocculant AN926SH which concentration is between100to300mg/L. For the oil phase acidification back-flow liquid, the stability experiment of acidification oil analyzes that the acidification oil is a stable oil-water emulsion system. Firstly, the thermo chemical dehydration experiment is used, the demulsification temperature is75℃and the demulsification time is one hour,100mg/L MD series demulsifiers can reduce the water content of acidification to about25%. As the ultrasonic oil has25%high water content, the electric dehydrator trips during the experiment. Then the acidification oil needs ultrasonic dehydration. The best ultrasonic temperature is70℃. The first ultrasonic time is30min and the second ultrasonic time is10min. In the best ultrasonic conditions, water content of acidification oil can reduce from25%to about10%. As the ultrasonic oil has low water content, when it mixed with normal produced liquid under volume ratio (1:9,2:8,3:7,4:6,5:5), the electric dehydrator works normally.By the experimental data which are obtained from the research on JZ9-3oilfield and SZ36-1oilfield, the cooperative engineer designs treatment system which is suitable for the offshore platform. The treatment system includes pretreatment module, deironing filtration module, acidification treatment module and medicine addition module.