Barium Sulphate Scaling Prevention

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Author(s) Obot Itoro | Okotie Sylvester | Dulu Appah
Pages 254-263
Volume 5
Issue 4
Date April, 2015
Keywords Scale Precipitation, Barium Sulphate, Formation and Sea Water, Inhibitors, Oil and Gas Production, Flow Lines, Production Facilities and Inhibitor Efficiency.

Abstract

Mineral salt precipitation is a flow assurance issue during oil and gas production which often results in significant decline in productivity and expensive work-over operations if its formation is not managed effectively. Formation water produced alongside oil and gas contain significant amount of mineral salts which causes a high risk of precipitation inside the reservoir due to changes in temperature and pressure. A proper understanding of the formation containing these salts is necessary to minimize the severity of their effects especially in the plugging of tubes, valves, pumps and other production flow systems which can potentially lead to well abandonment. Studies pertaining to the challenge of oilfield scaling by Barium Sulphate have been made. Incompatibility between the formation water and seawater was observed to be the major cause of precipitation of Barium Sulphate. Barium Sulphate scale is relatively more difficult to treat, therefore preventing its formation through the use of scale-control chemicals (inhibitors) is the most effective means of containing scale formation. Application of Scale Control chemicals into the vicinity of the wellbore formation either by squeeze treatment or continual injection has been observed to manage the precipitation challenge very effectively. The goal of this study is to investigate the efficiency of polymers as a scale inhibitor in a typical petroleum production system and quantify their sensitivity to concentration, composition, saturation as well as the water/solution chemistry. The results obtained from the experiment shows that a low molecular weight of about 2200 provides excellent inhibitory performance in the Inhibitor Efficiency test conducted for less than 22 hours. Optimal inhibition efficiency was noticed at a concentration of 5 ppm and an increase in acidity of the solution leads to increase in the inhibition efficiency of the Inhibitor.

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