Compound And Evaluation Of Barium Sulfate Scale Inhibitor In Oilfield

During the production of well fluids, water content increasing or injecting water to enhance oil production,scale will deposit. They can deposit on equipment in the well causingit to malfunction. Scale can occur anywhere along the productionconduit narrowing the internal diameter and blockingflow andcan even occur as far along as the processing facilities.BaSO4is hard to be removed, so only can stop them to form.This research aims at synthesizing one kind of scale inhibitor to prevent barium sulfate scale formation in H oil fields, this scale inhibitor has good performance and environmental. Predicting thebarium sulfate scale in wells HS1,HS2and HS3, proposal an optimal concentration to inject scale inhibitor in H oil field.(1) In the study, static method was used to evaluate the scale performance of green scale inhibitor PESA, PASP and organic phosphonic acid inhibitors, copolymers scale inhibitors, choosing PESA as the main scale inhibitor, PBTCA, AMPS as the additive.(2) By using orthogonal experiments, the results show that when the PESA and PBTCA, AMPS concentration ratio of8:1:0.5, the new scale inhibitor LJ-51has the best performance. LJ-51is one kind of weak acid scale inhibitors with pH value of6.3, and density of1.32g/cm3. LJ-51has better scale inhibition performance on barium sulfate scale than the common scale inhibitors. LJ-51almost cann’t remove the barium sulfate scale.(3)Analysing the machanism of LJ-51by using infrared spectra, electron microscope and electrical conductivity, LJ-51can chelate the metal ion and distortion lattice, preventing the growing of barium sulfate scale. Beyond that, LJ-51can protect the carbon steel from corrosion.(4) The study predicting the scale formation of the three wells by two methods, Saturation Index and Saturation Coeddicient, with the result that barium sulfate scale forms in the three wells, main at the wellhead, a spot of calcium carbonate and calcium scale forms at the downhole. Confecting the formation water of H oil field, study the performance of LJ-51effection on formation water, result with the optimal concentration of LJ-51for H oil field is12mg/L. in order to improve the effection on calcium carbonate, LJ-51need mix with PBTCA, the ratio is8:2.