STUDY OF CALCIUM SULFATE SCALING INDEX TENDENCY CALCULATIONS AT DIFFERENT TEMPERATURE CONDITIONS IN INJECTION WATER SAMPLES FROM OILFIELDS

Tjuwati Makmur

Scientific Contribution Oil and Gas
Vol. 30 No. 3 (2007): SCOG

Calcium sulfate scale is a type of scale found in petroleum industry and shows seriousproblem, because it can plug pore media and cause a decrease in production rate. Actual calcium sulfate (CaSO j concentrations ofSl, S2, S3 and S4 injection watersamples were in the range of 0.0208 to 0.4583 meq/l. While, the values of solubility ofSI, S2, S3 and S4 water samples at 77,145 and 177°F are in a range of 23.20 to 27.43meq/l. Based on the results of calcium sulfate scaling tendency calculations showed thatthe values of solubility of SI, S2, S3 and S4 water samples at various temperature condi-tions (77,140 and 175°F) are higher than actual CaSO4 concentrations for the sarne■water samples. No occurrence of CaSO4 scale was found in all analy.ed injection watersamples at different temperature conditions (77,140 and 175°F). Key words : calcium sulfate scale, scaling index tendency calculation, solubility of injec-tion water sample and actual CaSO4 concentration.