![]() ![]() They have affected both conventional and solution mining in several ways. ![]() « lessĪnomalous features in Gulf Coast Salt domes exhibit deviations from normally pure salt and vary widely in form from one dome to the next, ranging considerably in length and width. The history of operational problems, only some of which appear to be a matter of public record, combined with the potential for encountering escaped product from other operations, renders the Stratton Ridge salt dome a less-than-desirable site for SPR purposes. Many of these difficulties may be related to on-going differential movement of individual salt spines or to lateral movement at the caprock-salt interface. Although detailed information is difficult to come by, widely accepted industry rumors are that numerous existing caverns have experienced major operational problems, including salt falls, sheared casings, and unintended releases of stored product(s). More broadly speaking, the past history of cavern operations at the Stratton Ridge salt dome indicates that operation of potential SPR expansion caverns at this site may be difficult, and correspondingly expensive. However, such reconfiguration would be subject to limitations related to land-parcel boundaries and other existing infrastructure and topographic constraints. Repositioning of the proposed cavern field is possible, as sufficient currently undeveloped salt acreage appears to be available. A 300-ft distance from this boundary is likely to be the minimum acceptable stand-off, from both a geologic and a regulatory perspective. In places, the distance from this structural boundary to the design-basis caverns is as little as 150 ft. This structure transects the salt stock and subdivides it into an shallow western part and a deeper eastern part. The easternmost set of conceptual caverns are located within a 300-ft buffer zone of a very major boundary shear zone, fault, or other structural feature of indeterminate origin. The current conceptual design layout of proposed caverns for such an expansion facility is based upon a decades-old model of salt geometry, and it is unacceptable, according to this reinterpretation of salt dome geology. Past development of underground caverns significantly limits the potential options for use more » by the SPR. This geologic technical assessment indicates that the Stratton Ridge salt dome may be considered a viable, if less-than-desirable, candidate site for potential expansion of the Strategic Petroleum Reserve (SPR). The Stratton Ridge salt dome has been intensively developed, in the desirable central portions, with caverns for both brine production and product storage. The dome is approximately 15 miles south-southwest of Houston. ![]() The Stratton Ridge salt dome is a large salt diapir located only some ten miles from the currently active Strategic Petroleum Reserve Site at Bryan Mound, Texas. Additional study of brine disposal methods and hurricane surge probabilities are needed to establish design parameters and cost estimates for storage. = 100 yrs but would not affect cavern stability. However, the large size of the Chacahoula salt dome suggests more » that there is significant design flexibility to deal with such local geologic issues. The proposed cavern field may be affected by a boundary shear zone, located between the two salt spines. These regions of overhang should present no particular design issues, as the conceptual design SPR caverns are located in the western portion of the dome. Two mapped areas of salt overhang, located on the eastern and southeastern flanks of the salt stock, are present below -8000 ft. The dome appears to comprise two separate spine complexes of quasi-independently moving salt. Below this elevation, the flanks of the dome plunge steeply in all directions. The crest of the salt dome is relatively flatlying, outward to an elevation of -4000 ft. The shallowest known salt is present at 1116 ft, subsea. The overall salt dome appears to cover an area of some 1800 acres, or approximately 2.8 square miles, at a subsea elevation of 2000 ft, which is near the top of the salt stock. Strategic Petroleum Reserve, comprising sixteen 10-million barrel underground storage caverns. The Chacahoula salt dome, located in southern Louisiana, approximately 66 miles southwest of New Orleans, appears to be a suitable site for a 160-million-barrel-capacity expansion facility for the U.S. ![]()
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