(395b) Dynamic Breakthrough Studies of Scale Inhibitor Used in Petroleum Sea Production

Sea water contains significant sulfate concentrations ions and when mixed with the water produced during petroleum exploration, which may contain strontium, barium and magnesium ions, sulfate deposition may occur. Other possible scale that may develop in oil sea wells is originated from calcium carbonate, normally formed by high pressure differences and high temperatures in the petroleum wells. Some factors may affect the scale formation, like temperature, salinity and carbon dioxide partial pressure. The scales may deposit at the wellhead and in production lines, resulting in loss of productivity, and may require removal and prevention techniques, like the squeeze treatment. The squeeze technique involves injecting a scale inhibitor in high concentrations under pressure within the reservoir. Experiments using coreflood tests are normally performed to simulate the squeeze treatment in laboratory scale in order to estimate the interaction between the scale inhibitor and the petroleum rock. In this study we evaluate the use of a small column technique under constant temperature and flow to determine breakthrough curves of the inhibitors in these systems. Our experiments were performed at 303.15 K and flowrate of 0.1 mL/min. The effluent of the column at given times was dosed using a inductively coupled plasma optic emission spectrometer (ICP-OES) to estimate the phosphorous (scale inhibitor active phase) concentration, yielding amounts adsorbed of 0,032; 0,054; and 0,064 (mg phosphorous)/(g rock) for a rock bed of 57% porosity, with inhibitor concentrations of 1000, 2000 and 3000 ppm, respectively.