Research On Prediction And Prevention Of Asphaltene Deposition In Crude Oil

In the mining process of raw crude oil,the change of oil quality,temperature and pressure of the system and the production system will lead to the deposition of asphaltenes in the wellbore,as production progresses,asphaltene deposition might clog the wellbore,even blocked the wellbore.Currently oil field worker can not accurately grasp the deposition rate of asphaltenes in the wellbore,the deposition thickness and position,and can not develop effective measures to eliminate.To solve the above problem,this paper on the basis of qualitative research on the pitch deposition mechanism,conducting impact factors of asphaltene deposition,this paper established the asphaltene deposition dynamic prediction model,and developed a fast and efficient new asphaltene solvent.This paper obtained the following understanding:(1)Asphaltene molecular structure is very complex,through its association with the formation of small particles,through precipitation,aggregation of large particles,and finally adsorbed on the wellbore wall to complete the whole process of asphaltene deposition.Asphaltene deposition rate and position mainly by the crude nature,pressure and temperature of the system and the production system decision.(2)The crude nature of the Halahatang three wells in Block X showed that three wells are Intermediate oil,asphaltene content of 4.45%-6.32%;C7 + components accounted for more than 95%;crude oil constitute is complex,containing a large number of hydroxyl,amino,carboxyl,carbonyl group and an aromatic ring,a fused ring group,easily lead to aggregation and precipitation of asphaltene;oil-like fluidity and asphaltene content of the oil sample negative correlation.(3)Study on characteristics Halahatang X Block oil deposits clogging material showed that the blockage to the plate-like structure of asphaltenes deposits mainly asphaltene content of about 65%;asphaltene molecular association,plate-like aggregates formed relatively dense structure,as in the wall adsorption,deposition,removal more difficult;the clogging sediments containing impurities adsorbed on the surface of the asphaltene aggregate,these impurities may be sulfur,metals,minerals and clay minerals.(4)The establishment of asphaltene deposition dynamic forecasting model that can accurately predict asphaltene deposition rate,thickness,and location of oil deposits in the wellbore.Asphaltene deposition of oil wells and predict the sensitivity analysis and the results showed that:the production of gas-oil ratio,the deposition of the deeper,faster deposition;hydraulic smaller,deeper deposits position,the faster the deposition;asphaltene content is higher,the faster the deposition rate;the higher the starting point of asphaltene deposition pressure,the deeper the deposition position,the faster the deposition.(5)We developed a fast and efficient new asphaltene solvent T-D,the best ratio based agent:organic solvent:penetrant = 60%:25%:15%.Asphaltene solvent T-D indoor evaluated.The results showed that the solvent TD can be effectively dispersed in crude oil asphaltene particles;when solvent TD and asphaltene volume mass ratio is 2:1,the dissolution rate is 88.8%?93%;solvent TD on crude inhibition rate is 74.8%.