U.S. Coast and Geodectic Survey. 1967. United States Coast Pilot 5 U.S. Department of the Army. 1973. Report on Gulf coast deepwater U.S. Department of Commerce. 1971. Gulf Fisheries-1968. CFS No. 5537. NMFS, Wash., D. C. U.S. Department of Commerce. 1972. Texas landings, December 1971. CFS No. 5812. NMFS, Washington, D. C. U.S. Department of Commerce. 1972a. Texas landings--Annual Summary, 1971. CFS No. 5923. NMFS, Wash., D. C. U.S. Department of Commerce. CFS No. 6200. 1973. 1970 saltwater angling survey, National Marine Fisheries Service. Wash., D. C. U.S. Department of Commerce. 1973a. Fisheries of the United States, 1972. Current Fisheries Statistics No. 6100. National Marine Fisheries Service, Washington, D. C. U.S. Department of Commerce. 1973b. Texas landings, December 1972. CFS No. 4680. Fish and Wildlife Service. U.S. Department of the Interior. 1969. Gulf Fisheries-1967. Wash.,D. C. U.S. Naval Weather Service Command. 1970b. Summary of synoptic Texas A & M University. 1973. · Wathne, F. 1959. Summary of exploratory long-line fishing for tuna in Gulf of Mexico and Caribbean Sea. 1954-1957. U.S. Dept. Interior. Fish and Wildlife Serv. Washington, D. C. Comm. Fish. Rev. Vol. 24 No. 4. pp. 1-25. A. A Description of Oil and Gas Operations Including a Timetable for this Proposal In order to locate hydrocarbon deposits, the oil industry must analyze the substructure of the continental shelf and slope. The prime objective of the structural analysis is to locate geologic features, such as local upwarping of the sediments, faulted structures, and piercement salt and/or shale domes, which are favorable for the accumulation of petroleum. A knowledge of the subsurface geologic environment is also necessary to detect near surface conditions, such as recent faulting or high pressure zones, which are potential hazards to exploration and production operations. Once hazardous conditions are identified, drilling programs are modified to assure safety of operations. Prior to a call for nomination of lease sale tracts, industry normally conducts regional geophysical surveys of the area of interest. These surveys provide a network of modern state-ofthe-art common depth point (CDP) seismic lines, using approximately a 4 mile-by-4 mile grid spacing to provide data for reconnaissance mapping. In some cases an even closer 2 mile-by-2 mile line spacing may be used. After the Department issues a call for nominations, industry initiates the collection and interpretation of even more detailed seismic data in order to evaluate potentially productive tracts, and to formulate reasonable bid offers. In seismic exploration, a survey vessel travels along a predetermined path, guided by a sophisticated electronic navigational system and towing seismic signal generating and recording equipment. The signal generated by the energy source is a series of small amplitude seismic pulses that travel at the speed of sound through the water and sediments below, where they are reflected and refracted by the underlying strata. An array of sensitive detectors, hydrophones, towed by the vessel record incoming seismic waves on magnetic tape. After extensive processing, these recordings are displayed in the form of vertical cross sections. These seismic profiles are interpreted to identify those areas where the sediments are arched, faulted, or pierced by salt or shale domes, where they thicken or thin, and where reef structures occur. By assembling cross sections, run in various directions, a three-dimensional picture can be constructed, indicating the location, size, and form of geologic structures favorable for oil and gas accumulation. This information is normally displayed in the form of subsurface seismic contour maps. In the early years of offshore exploration, the energy source for the seismic wave was explosive charges detonated in the water layer. Because of the hazards associated with the use of dynamite to the seismic vessel, crew, and natural marine life, new equipment and methods have evolved within the last five years and now account for well over 95% of marine seismic activity. 1/ In particular, the use of a vibrator system, sparkers, air guns, and gas guns now provide excellent seismic data, with no observed harmful effect on the marine environment. In January 1969 and October 1970, due to concern about the effect of acoustic energy sources on the ecology of the marine environment, a comprehensive investigation of the effects of compressed air charges on the water column, water bottom and marine life (oysters) was conducted by marine biologists of the Louisiana Wild Life and Fisheries Commission. The experiments were conducted in Sister Lake, Terrebonne Parish, Louisiana, in water depths from three to five feet at two separate locations: (1) hard shell bottom; (2) soft mud bottom. Normal seismic survey operating procedures were used in the tests. The evidence from the tests, as reported by the Commission, indicates no damage to the water, water bottom, or oysters from the air blasts. (The oysters were examined daily for approximately three months after the completion of the tests for evidence of mortality or abnormality.) General observations indicated that no fish or other marine animals were affected. 2/ 1/ Taken from Testimony of E. 0. Bell, past President, Offshore Operators Committee, presented at OCS Public Hearing, Houston, Texas, February 22, 1973. 2/ Field Notes, 1969, 1970. Louisiana Wild Life and Fisheries Commission; New Orleans, Louisiana. |