Exploration and Production Technologies
Targeting Reserve Growth Opportunities in the Northern Gulf of Mexico Basin  

DE-FC26-98FT40136

Goal:
The goal of this project is to increase domestic natural gas reserve growth from offshore reservoirs through the use of proven secondary gas recovery technologies.

Background:
This project investigated an innovative characterization approach to define the structure, stratigraphy, and hydrocarbon character in mature areas in the northern Gulf of Mexico. This multidisciplinary technique was used to identify bypassed natural gas resources and to predict regional trends in hydrocarbon accumulation. The approach incorporated state-of-art technologies and science (e.g., 3-D seismic interpretation, modern quantitative well log analysis, state-of-art sequence stratigraphic and sedimentalogical interpretation, and production data) to develop optimized secondary gas recovery strategies. The research resulted in identifying opportunities for infill drilling and recompletion of existing wells to demonstrate that the application of advanced reservoir characterization technologies can vastly increase production efficiencies and increase reserves in the offshore environment.


Map of Vermilion and South Marsh Areas showing the study’s primary target fields, Starfak and Tiger Shoal, as well as surrounding fields.

Performer: University of Texas at Austin Bureau of Economic Geology

Location:
Austin, TX 78713

Project Impact:
Within the study area, the project estimates that more than 41 percent of known gas in the GOM Miocene strata remains to be produced. This research project showed that integrated sequence-stratigraphic analysis can be used to create a framework of unparalleled utility within which to examine resource distribution, seal quality, petrophysical parameters, and reservoir presence. By applying this method to accurately define structure, stratigraphy, and regional trends in hydrocarbon accumulations, strategic infill-drilling programs in mature fields can be designed that allow prospects for reserve growth opportunities to be developed expeditiously.

Accomplishments: 
Significant recoverable gas resources remain undiscovered, undocumented and unproduced in the Miocene strata of the northern Gulf of Mexico (GOM). More than 41 percent of the known gas in the GOM Miocene strata remains to be produced. This four-year research project was initiated to develop new play concepts, new processing designs and imaging tools and identify new resource addition opportunities that will enable small and large companies to arrest the decline in capital performance and extend the life gas exploration and development on the GOM shelf.

One of the most significant plays remaining in the Miocene of the northern GOM is the numerous lowstand prograding wedges that characterized the Miocene-age depositional shelf-edge locations throughout the Gulf subsurface. A variety of sub-regional reservoir sandstones pinch-out within thick, stacked lowstand prograding wedges. Their setting within slope and basinal shales creates ideal conditions for potential hydrocarbon migration and entrapment. They are composed of distal, medial and proximal portions each identifiable in logging cross-sections and mappable within stratal slice (proportional sliced) images. Within the study area, the lowstand prograding wedge sandstones of the Robulus “L” zone contain the most gas reserves of any identified zones of opportunity: 41 percent of the total oil and gas in place (421 Bcf) and 40 percent of unrisked reserves (251 Bcf). The combination of unique stratal slice imaging of the seismic performed within a sequence framework of key chronostratigraphic surfaces enable geoscientists to define these resource targets and reduce both their risk and cycle time in exploiting these reserve addition opportunities.


Amplitude Stradal Slice of a Prograding Wedge Sequence

Current Status and Remaining Tasks:
This project is complete and the final report, "Targeting Reserve Growth Opportunities in the Northern Gulf of Mexico Basin: Transferring Secondary Gas Recovery Technology to the Offshore Environment," is available. Please see "Additional Information" below.

Project Start Date: September 30, 1998
Project End Date: September 30, 2002

DOE Contribution: $ 3,386,580
Performer Contribution: $ 5,565,000

Contact Information:
NETL – Gary Sames (gary.sames@netl.doe.gov or 412-386-5067 ) 
UTA – Lesli Wood (lesli.wood.beg@utexas.edu or 512-471-0328)

Additional Information:

Final Project Report [PDF-208MB]

Plate 1 [PDF-1.54MB]

Plate 2 [PDF-13.8MB]

3-D Seismic Detection of Undrilled Prospective Areas in a Mature Province, South Marsh Island, Gulf of Mexico [PDF-294KB]

Frequency Miocene Sequence Stratigraphy, Offshore Louisiana: Cycle Framework and Influence on Production Distribution in a Mature Shelf Province [PDF-1639KB]  

 
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