ABSTRACT: Coastal Geological Phenomena Affecting Petroleum Production

S. Penland, C. G. Groat

Oil and gas production in the northern Gulf of Mexico is affected by a complex set of coastal hazards ranging from catastrophic coastal land loss, rapid relative sea level rise, and repeated hurricanes to environmental liability associated with operations. An understanding of the processes driving coastal change helps deal with these hazards effectively.

The coastal wetlands of the Mississippi River delta and chenier plains are experiencing catastrophic loss at rates of 75-100 km²/yr. Oil and gas facilities along the coast are faced with shoreline retreat rates of 10 to 20 m/yr. As a consequence, many facilities must be protected or moved. At East Timbalier Island, a massive sea wall backed by secondary revetments was constructed to protect oil and gas operations in Timbalier Bay. To the west, the Lake Pelto oil and gas field is faced with the loss of the protective Isles Dernieres barrier island arc in the next decade. This extreme pattern of coastal erosion and wetland loss is a consequence of a rapid rise in relative sea level driven by subsidence. Relative sea level rise rates range between 0.4 and 0.5 cm/yr for the che ier plain and 1-1.5 cm/yr for the delta plain. Hurricanes which strike the Louisiana coast every 2-5 years accelerate erosion and damage production facilities.

In addition, the perception that oil and gas access canals, pipelines, and discharges are responsible for the majority of the coastal land loss in Louisiana is firmly entrenched and can only by overcome by credible environmental research programs and industrial stewardship of the coastal zone.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990