Modified Urea-formaldehyde Resin Sand Process Research And Field Applications

In this paper, the reasons of sand production in oil and gas field and its disadvantages were reviewed. In the same time, sand production mechanisms and its prediction methods were also narrated. According to the situation of domestic and international sand control development, have summed up the sand control methods since 1940s, and emphasized on the chemical methods of sand control, technologies, using conditions and its advantages and disadvantages respectively. In addition, the paper analyzes the developmental orientation of sand control technologies, and studies a lower toxic modified urea-formaldehyde resin, which uses to sand prevent. This resin has many advantages such as its lower poison, cheap price of raw material, simple applied technology, less polluted environment and non-pungent taste.Through experiment in a large amount, a new type of modified lower poisonous urea-formaldehyde resin was synthesized by reducing molar ration of urea and formaldehyde, adding modifier and adjusting synthesized condition such as reaction temperature, reaction time, pH etc. By characteristic testing, we found this urea-formaldehyde resin has less free formaldehyde, lower viscosity, water-resisting, only little dissolved in acid, stability in deposit and has plastic properties after curing. It is fit to apply to sand control, water plugging, sealing and so on. By infrared spectrum analyzing, liquor viscosity and free formaldehyde assaying after reaction, it accords to the anticipated product. According to shortfall and no shortfall oil or water well, methods of sand control were applied respectively. To the shortfall, we use sand-laden fluid carrying quartz sand to the job implementation level, then inject sand consolidation fluid, and research temperature, salinity etc factors influence the curing reaction. To meet the demand of injecting time, time-delay curing agent was selected; To adjust the velocity of curing reaction, hexamethylenetetramine was added; To enhance the strength after concretion, coupling agent was chose. At the same time, the affect factors—particle size of sand, water and polyvinylalcohol were also analyzed. Finally, the composition for sand control of shortfall in oil or water well was concluded. To the no shortfall, we use urea-formaldehyde solution to sand prevent, through orthogonal design experiment the key factors and subordinately factors were found, and we get a basic composition which may be adjusted according to the request of construction on site.This urea-formaldehyde resin to sand control applied in Yan muxi 6-24 well and 607# well, Tuha oilfield, xinjiang. After job implementation, sand influx reduces to minimum in the two wells, and the rate of water injection and oil extraction were enhanced. So, the effect of sand control was distinct, and the stratal configuration was consolidated.