Date of Award

Spring 1-1-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Geological Sciences

First Advisor

Paul Weimer

Second Advisor

Renaud Bouroullec

Third Advisor

Geoff Dorn

Abstract

The Blasillo Field is a mature field located in the Salina del Itsmo Basin in the southern part of the Gulf of Mexico. An analysis of 71 wireline logs and 930 square km of 3D seismic data was done to evaluate the potential for infill drilling based on an improved understanding of reservoir geometry. Reservoirs are primarily upper Miocene turbidites deposited in bathyal water depths. Average porosity is 19 % and permeability is 215 mD. The field dips to the south along the flank of shallow allochthonous salt feature. The field has a combined structural/stratigraphic trap with three-way closure with an updip pinchout of the reservoirs.

The field is divided into 14 sequences, each separated by regional continuous shales. Seismic and log trends indicate transport from the south to southwest to the north and northeast. Five distinct wireline log lithofacies are recognized. Reservoir sands were primarily single to multistory channel-fill complexes varying from erosional to mixed erosional-aggradational channels. Lateral accretion packages are present within the producing zones indicating migrating channels.

To date, development wells have been drilled at 400-m spacing. Results of the study indicate considerable potential for infill drilling. The depositional systems interpreted are considered semi amalgamated and could present barriers between the reservoirs levels and constitute areas of opportunity to drill infill wells closer to the pre existing wells. Considerable exploration potential is still present in the regions below the shallow allochthonous salt. Pre-stack depth migration processing will be necessary to image the potential traps.

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