USGS1983
Louisiana's coastal wetlands, alone with their well-drained urbanized strips, have been significantly affected by the oil and gas industry. Onshore, more than 6,300 exploratory wells and more than 21,000 development wells were drilled in Louisiana's eight southernmost parishes between 1937 and 1977. Nearly all those wells were in wetlands or inland water bodies. The wetlands, totaling more than 2 million hectares (ha), extend inland to roughly latitude 30? N, and are about 15 percent forested swamp and 85 percent nonforested marsh. Inland waters within the Louisiana coastal zone total more than 1 million ha. Nearly all these waters are quite shallow. More than 235,000 ha of this coastal area is used for major activities associated with the extraction of oil and gas. Production in the eight southern parishes peaked in 1970 to 120 million m3 of oil and 172 billion m 3 of gas. Connecting extensive onshore fields--and also servicing offshore fields--are intricate networks of canals for pipelines and maritime traffic related to the oil and gas industry. Offshore, more than 2,400 drilling and production platforms had been installed by May of 1981. Oil production from wells in both Federal and State waters off Louisiana peaked at 71 million m3 in 1972. Offshore gas production continues to increase, with 131 billion m3, in 1979. Since the early 1950's southern Louisiana's population has shifted from remote rural areas in the marshes to the more densely settled areas on the natural levees and beach ridges where employment is available in oil-field support industries and businesses. In 1975, in the 14 primary settlement clusters within the coastal wetlands, more than 3,600 advertised business activities were connected directly to the oil and gas industry. This compares to about 1,200 such activities in 1955, at the start of offshore development. These businesses are listed as water transportation, transportation equipment, pipelines, chemicals, special trade contractors, and petroleum refining, as well as actual oil and gas extraction. Area measurements of urban land uses reveal a major concentration of industry and transportation facilities along the navigable waterways. Ship and rig construction are important activities; of 148 fixed drilling platforms under construction in the United States in March 1981, 94 were being built in Louisiana to be barged out into the Gulf of Mexico and beyond. Of the 122 petroleum-industry support boats being built in the United States in 1976, 82 were in Louisiana shipyards; the worldwide total was estimated to be only about 200. In 1980, the Nation's marine con- tractors were building 129 logistic support vessels. Louisiana-based firms had 98 vessels under construction.