ABSTRACT

Future hydrocarbon finds on the upper and lower continental slope and rise of Texas and Louisiana well necessitate innovative methods for the construction of platforms and pipelines in a very difficult engineering and complex geological environment. There are 105 intraslope basins and eight submarine canyons on the continental slope of the northwestern Gulf of Mexico, all of which may be prime targets for hydrocarbon production. Examinations of the physiographic, geophysical, and geotechnical characteristics of the intraslope basins of Pigmy and Vaca basins and the Alaminos submarine canyon are used as examples to typify the various engineering and geological constraints that are most likely to be encountered on the continental slope and rise and along the Sigsbee Escarpment in the northwestern Gulf of Mexico. High-resolution bathymetry identifies such constraints as high angle intraslope basin walls; walls that exceed 40 degrees are common. Sediment slumps and other instabilities, such as long-term sediment creep and other affects of halokinesis and contemporaneous faulting, are evaluated from high-resolution geophysics. The small canyons and large gullies that dissect the perimeter of Alaminos Canyon, which may be the results of both recent and old turbidity currents and debris flows, are structures that require engineering consideration in the implacement of seafloor structures in, near or down-slope of these features.