Scale Removal And Inhibition In Alkalescent Alkaline/Surfactant/Polymer Flooding Surface System At Xinjiang Oilfield

Produced liquid from the old blocks of xinjiang oilfield contains about 90% water.In order to realize stable production of 10-million-ton crude oil continuously,xinjiang oilfield has carried out a ASP flooding test project.The scaling problem of oilfield surface systems becomes more and more serious since ASP flooding project was put into production.In this paper,descaling and anti-scaling countermeasures are formulated according to the field conditions to ensure the industrialization and commercialization of alkalescent ASP flooding.Water quality of oilfield surface system is tested in detail,and the composition of scale samplings at key nodes of the system is analyzed.The effects of ASP concentration,reaction time,temperature,aeration,pressure,flow rate,purifying agent,demulsifier,corrosion,mud and sand on water quality scaling are studied.Corrosion is the most serious in the vacuum furnace.The dynamic corrosion rate is faster by several times than the static corrosion,and dynamic corrosion rate is 0.0913 mm/a at 50?.The injection and distribution system adopts the electromagnetic treatment method for scale prevention,and a strong pipeline magnetic protector is added to the injection pipe segment,which shows a good performance.The problems caused by scale formation have not appeared so far after the installation of the equipment.The method of combining process and chemical method is used in the produced liquid treatment system uses to prevent scaling.In the facet of process,the dewatering time & temperature in the first stage settle drum and sand removal of a sedimentation tank are taken into account.Low temperature crude oil treatment for ASP flooding is studied so as to reduce the influence of temperature,sand and ion concentration on scaling.In the facet of chemical method,the corrosion and scale inhibition agent is prepared for the site-specific water quality and performed well.The reference dosage is 20mg/ l-50 mg /L,and the addition position is 72# station at the produced liquid inlet.The corrosion inhibition efficiency is higher than 85%,and the scale inhibition efficiency is more than 90%.