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New product for inhibition of calcium carbonate scale in natural gas and oil facilities based on aloe vera: Application in Venezuelan oilfields

Abstract:

Scales are secondary deposits constituted by inorganic chemical compounds present in an anthropogenic system. They are generated by changes in the thermodynamic, kinetic and hydrodynamics conditions[1] when formation fluids are produced, or by mutual physicochemical incompatibility between production and injection fluids. Therefore, they can jeopardize the integrity, good condition and useful lifetime of geological formations, producing and injection wells, surface facilities and pipelines, increasing the industry operation costs. Generally, these problems had been mitigated by using conventional technologies based on chemical compounds (polyphosphate, carboxylic compounds, among others), that generate environmental liabilities and represent high costs for the industry. Recently, PDVSA Intevep, S.A. has developed a scale inhibitor product based on Aloe vera plant chemical component [2], that offers equal or in some cases better efficiency than conventional chemical treatments, on the same conditions of evaluation. In addition, it offers the potential benefits of a lower environmental impact. In this study, the performance of this anti-scale polysaccharide-based product was evaluated in the laboratory, simulating oil and water transfer system from flow stations to tanks, producing wells with high water content and injection wells. After, the product was evaluated in pilot field tests in two wells during about 50 days each: (1) Barinas's production well with about 3200 BPD, 98% water and high scale tendency by Oddo-Thompson method at bottomhole. (2) Monagas's production well with about 2200 BPD, 74% water and high scale tendency by Stiff and Davis method at wellhead. In both cases, the pilot field tests were successful. The scale inhibitor product developed was more efficient than commercial products used in those production wells. Copyright 2009, Society of Petroleum Engineers.