LESCHAK, PAMELA, Amoco Offshore Business Unit, New Orleans, LA; and R. L. AMES, L. M. ROSS, and J. REBER, Amoco Production Research, Tulsa, OK

ABSTRACT: South Marsh Island Block 128 Field: (Editor's Title)

South Marsh Island Block 128 Field is located on the continental shelf of offshore Louisiana, approximately 160 miles southwest of New Orleans. This field is described as a large, complexly faulted, salt-cored, anticlinal shale ridge. Oil and gas accumulations are associated with both structural and stratigraphic traps on the crestal and flanking areas of the salt-related shale diapir. These hydrocarbons are distributed in over 15 proven pay zones within middle and lower Pleistocene sands.

Geochemical analysis of 50 oils from this field show reservoir continuity relationships that support field development programs. Oils in laterally continuous sands have relatively uniform composition (as defined by whole oil gas chromatography); whereas oils in compartmentalized units evidence compositional differences. Information about oil compositions can be used to aid in reservoir descriptions and to evaluate technical risks at the prospect level. The chemical fingerprints of the oils will also influence our well repair and recompletion plans.

Whole oil, gas chromatography is the analysis of choice for these well head samples because it is fast, inexpensive, and easy to apply. These qualities fit Amoco's strategy to provide appropriate technology to our geoscientists and engineers to address current field development problems.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.