Publications

Abstract not provided.

Two mitigation strategies including the use of corrosion resistant alloys (CRA) for the tubing and the application of a corrosion inhibitor and anti-fouling package in the water were used in the laboratory simulation of corrosion in large oil coolers at US Strategic Petroleum Reserve. A closed-loop, recirculating system was designed and constructed. The corrosion sensors were monitored over time using a commercially available linear polarization resistance (LPR) meter. The ERW steel exhibited significant localized attack along the entire weld root, in addition to pitting along the rest of the surface, as observed on the seamless tubing.

Abstract not provided.

The goal of this study was to first establish the fitness for service of the carbon steel based oil coolers presently located at the Bryan Mound and West Hackberry sites, and second, to compare quantitatively the performance of two proposed corrosion mitigation strategies. To address these goals, a series of flow loops were constructed to simulate the conditions present within the oil coolers allowing the performance of each corrosion mitigation strategy, as well as the baseline performance of the existing systems, to be assessed. As prior experimentation had indicated that the corrosion and fouling was relatively uniform within the oil coolers, the hot and cold side of the system were simulated, representing the extremes of temperature observed within a typical oil cooler. Upon completion of the experiment, the depth of localized attack observed on carbon steel was such that perforation of the tube walls would likely result within a 180 day drawdown procedure at West Hackberry. Furthermore, considering the average rate of wall recession (from LPR measurements), combined with the extensive localized attack (pitting) which occurred in both environments, the tubing wall thickness remaining after 180 days would be less than that required to contain the operating pressures of the oil coolers for both sites. Finally, the inhibitor package, while it did reduce the measured corrosion rate in the case of the West Hackberry solutions, did not provide a sufficient reduction in the observed attack to justify its use.

The intrusion of gas into oils stored within the SPR has been examined. When oil is stored in domal salts, gases intrude into the stored oil from the surrounding salt. Aspects of the mechanism of gas intrusion have been examined. In all cases, this gas intrusion results in increases in the oil vapor pressure. Data that have been gathered from 1993 to August 2002 are presented to show the resultant increases in bubble-point pressure on a cavern-by-cavern as well as on a stream basis. The measurement techniques are presented with particular emphasis on the TVP 95. Data analysis methods are presented to show the methods required to obtain recombined cavern oil compositions. Gas-oil ratios are also computed from the data and are presented on a cavern-by-cavern and stream basis. The observed increases in bubble-point pressure and gas-oil ratio are further statistically analyzed to allow data interpretation. Emissions plume modeling is used to determine adherence to state air regulations. Gas intrusion is observed to be variable among the sites and within each dome. Gas intrusions at Bryan Mound and Big Hill have resulted in the largest increases in bubble-point pressure for the Strategic Petroleum Reserve (SPR). The streams at Bayou Choctaw and West Hackberry show minimal bubble-point pressure increases. Emissions plume modeling, using the state mandated ISCST code, of oil storage tanks showed that virtually no gas may be released when H2S standards are considered. DOE plans to scavenge H2S to comply with the very tight standards on this gas. With the assumption of scavenging, benzene releases become the next most controlling factor. Model results show that a GOR of 0.6 SCF/BBL may be emissions that are within standards. Employing the benzene gas release standard will significantly improve oil deliverability. New plume modeling using the computational fluid dynamics code, FLUENT, is addressing limitations of the state mandated ISCST model.