(524a) Use of Anhydride Based Polymers as Scale Control Agents in Production of Heavy Oils

Although water flooding is one of the main oil recovery processes for conventional oils, but it has been also suggested for production of heavy oil [1]. In addition use of hot water or steam can improve recovery of heavy oil by viscosity reduction. Scale is deposition of inorganic minerals from brine and scale deposition occurs in reservoir and in production facilities. Scale causes corrosion, equipment damage and flow restriction causing lowering of production rate.

Calcium sulfate and calcium carbonate are two major precipitating salts causing formation damage in oil production fields. In this paper we present application of several synthesized anti-scaling polymeric agents based on maelic-anhydride. Some tests have been conducted for anti-precipitation tests with CaCO3, CaSO4 and Mg(OH)2 scales and calculating percent inhibition. The Scanning Electron Microscope (SEM) studies have been used to show photographs for CaSO4 scales with and without the presence of polymers. The influences of polymers on the morphological changes of the scales were examined extensively. It was observed that the inhibition ability on the calcium carbonate scale is much higher and even with 0.5 ppm dosage the efficiency is around 90-95% when the pH level is 10.45 at temperature of 70 C. For Calcium sulfate the efficiency was slightly lower and at 2-3 ppm level the efficiency of 70% was observed. CaCO3 and Mg(OH)2 are partially soluble alkane scales and it is possible to remove them by the use of strong acid where removal of calcium sulfate is very difficult and they are insoluble even in strong acids.

[1] Mai, A., Kantzas, A., Heavy Oil Waterflooding: Effects of Flow Rate and Oil Viscosity,? J Can Pet. Tech, Vol 48, No. 3, pp. 42-51, 2009.