Abstract

Deepwater Gulf of Mexico contains numerous geologic plays at different reservoir depths with proven hydrocarbon resource. Among these plays is the Wilcox, where exploration and appraisal drilling has increased since 2001, and reported successes indicate that the play holds significant producible hydrocarbons in the order of multi-billion barrels. However, depth, location, and reservoir characteristics of the offshore Wilcox play present various challenges to commercial development of the Wilcox formation even with today's technology.

This paper summarizes a study that focused on Wilcox reservoir properties. It reviewed publicly available data from the Deepwater Gulf of Mexico Wilcox play. The study identified reservoir and geomechanical properties as well as potential regional trends and challenges facing deepwater Gulf of Mexico exploration and development. In addition, a log-based analysis was used to estimate rock mechanical properties and assess the potential for sand production and compaction. Initially conducted in 2009, this study was updated in 2012 to incorporate additional well data available for the Deepwater Gulf of Mexico Wilcox formation.

As a result, the study has helped to gain a better understanding of the Wilcox play, so that a reservoir life cycle approach can be implemented to serve the energy sector for more informed reservoir development decisions and fit-for-purpose engineering designs.

Introduction

The Wilcox Formation in Deepwater Gulf of Mexico (GOM) is an Upper (or Late) Paleocene to Lower (or Early) Eocene age siliciclastic turbidites. Continued successful exploration and appraisal activities since the first deepwater well in the Baha prospect have shown the Wilcox to be a major world class hydrocarbon (oil) resource. Full field ultra deepwater oil production has commenced from the Wilcox in Great White/Tobago (2010) and Cascade/Chinook (2012). Nevertheless, commercial development of significant Wilcox discoveries requires new completion technology, in view of concerns with viable deliverability from low porosity and low permeability reservoir units with high bottom hole temperatures (>200 deg F) and pressures (>20,000 psia), and in water depths exceeding 4,000 ft.

Baker Hughes Inc. proactively embarked on a regional reservoir study of the Wilcox play to support its operations and technology developments for GOM and in particular address the Paleogene challenges. As part of that study, Gaffney, Cline and Associates (GCA) and GeoMechanics International (GMI), both subsidiaries of Baker Hughes, Inc. (BHI) carried out a regional property trend study of the GOM Wilcox formation in 2009 (updated in 2012) to identify the range and trends of the Wilcox formation petrophysical and geo-mechanical properties. The study provided insights into the reservoir characteristics impacting commercial development of the Wilcox play that can be addressed with present day technology and identify technology gaps. This paper summarizes the study approach and results of property trends established from available well data.

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