Hydrocarbon Traps Along Louisiana Offshore

Allen Lowrie, Neil Sullivan

A compilation of potential hydrocarbon trap types has been assembled for the Louisiana offshore, from coastal plain to abyssal plain. These potential traps are listed according to paleophysiographic provinces: coastal plain, shelf, shelf break, upper slope, middle slope, lower slope, and abyssal plain.

Characteristics of each trap are tabulated. The characteristics include tectonics, regional and local sedimentation rates and types, position within an evolving sequence as determined by sequence stratigraphy, duration of reservoir and/or trap creation, and sea level position. Regional geologic processes, such as salt tectonics, and approximate rates at which they operate are also listed.

Hydrocarbon traps are minor aberrations within the overall geological evolution of the northern Gulf of Mexico. This evolution is the result of interaction between Louann Salt extruded due to combining pressure of overlying sediments and multiple high-frequency (< 100,000-year periodicity) sea level/climate oscillations controlling sedimentation rates and location. The overall Gulf of Mexico basin evolved over 100 million years. A hydrocarbon province, such as the Flexure trend, evolved over a period of 1 million to 10 million years. An individual prospect probably formed in 100,000 to 1 million years.

There are two goals: (1) compile hydrocarbon traps types and (2) discover their location and geologic characteristics within an overall evolutionary scheme for the northern Gulf of Mexico. The significance is to aid explorationists in locating traps and to better understand the geology that formed them.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.