Experimental Study On Influencing Factors And Chemical Scale Inhibition Of Barium Sulfate Scale

With many oilfields having entered late in depletion development in China, scaling problem is growing worse to the oil production.Basing on extensive literature review, this paper studied and elaborated barium sulfate Scaling mechanism, chemical inhibition mechanism, and sulfate scaling prediction models. Factors and effects of barium sulfate scale experiments have been done in this study, and the impact of scaling in Huaqing Oilfield has been detailed investigated in this paper.According to the data from Hua Qing oilfield water injection and formation water Ionic analysis, we have selected two representative wells to do theoretical predictions and experimental studies about barium sulfate scale influence factor and the scaling trend. The results show that:if the injection liquid was mixed with30%clear water and70%formation water, the largest amount of barium sulfate scaling will occur; with the increasing of temperature,the amount of barium sulfate scale decreases; The factor like formation pressure, pH changing has little effect on barium sulfate scale; If increase the concentration of Ba2+and SO42-in the injection liquid, the amount of barium sulfate scaling will also be increased; If increase salinity, barium sulfate scaling amount will be decreased. By comparing Experimental resultswith the Scalechem fouling prediction software predictable results, all the conclusion from this study have been approved.From Experimental study about inhibitor selection and evaluation, a better-scale inhibitor TH-1and inhibitor complex (The composite ratio of Inhibitor DTPMP, TH-1, TH-607B is1:2:1, the composite ratio of Inhibitor DTPMP, TH-1is2:1) have been selected out at the inhibitor concentration is120mg/L, From experimental study about the inhibition effect and influence factors, we obtained various factors on inhibition trends:With increasing concentration of inhibitor, the inhibition rate increased; when the inhibitor concentration is constant, withBa2+and SO42-ion concentration increasing, the inhibition rate decreased; with the salinity increasing, inhibition rate increased and gradually goes stable; By rising the temperature, the inhibition rate significantly increased first, and then decreased gradually; Inhibition rate will get to maximum point when the pH value is neutral; pressure affect a little on the inhibition.Basing on studies above, the orthogonal experiment studied about the impact of barium sulfate scale inhibitor has been done. The order of influence factors about scale effect is:the concentration of Ba2+>the salinity>pH values> the concentration of SO42-> the temperature. This paper synthesizes the research results and developed a scale scheme for Hua Qing oil field Partial wells inhibition and inhibitor filling process.