DE-FE0009949

Goal
The overarching objective of the project is to significantly increase our understanding of the occurrence, volume and fine scale distribution of natural gas hydrate in the northern Gulf of Mexico using petroleum industry and Gulf of Mexico Gas Hydrate Joint Industry Project well logs.

Performer
The Ohio State University, Columbus, OH 43210

Background
A large quantity of natural gas hydrate certainly occurs within the sediments of the northern Gulf of Mexico; however, the total amount and distribution of gas hydrate across the basin is relatively unconstrained (Boswell et al. 2012, in press). Gas hydrate forms in the gas hydrate stability zone (GHSZ), which is the interval between the seafloor and the sediment depth at which gas hydrate becomes too warm to be stable (gas hydrate stability depends on temperature, pressure, and salinity). A thin GHSZ originates in Gulf of Mexico sediments at the seafloor in water column depths of ~500 m and thickens as the water column increases (Milkov & Sassen, 2001).

Gas hydrate accumulations have historically not been sufficiently mapped by exploration seismic, though some new approaches seem promising (e.g., McConnell & Zhang, 2005; Shedd et al., 2012 [in press]). Thus, most current knowledge of sub-seafloor natural gas hydrate in the Gulf of Mexico comes from hydrate-focused drilling cruises, particularly the Gulf of Mexico Gas Hydrate Joint Industry Project Legs 1and 2, and from models of organic matter deposition and methanogenesis in the Gulf of Mexico basin (Frye, 2008).

The focus of this project is to significantly advance the understanding of the distribution and volume of natural gas hydrate from the log- to basin-scale in the northern Gulf of Mexico. To accomplish this, over 1700 industry well logs (obtained from the Bureau of Safety and Environmental Enforcement) from wells that penetrate the GHSZ will be analyzed for occurrence of natural gas hydrate in both sand and clay reservoirs.The industry well log analysis will be coupled with analysis and high resolution modeling of the sand and fracture gas hydrate reservoirs using well logs collected during the Gulf of Mexico Gas Hydrate Joint Industry Project Leg 2. Finally, researchers will use modeling results from the JIP Leg 2 wells and the industry analysis as inputs to a Monte Carlo simulation to formulate an estimate of the volume of natural gas hydrates in sand reservoirs and all sediment types in the Gulf of Mexico.

Impact
The project will significantly increase our knowledge of the nature and occurrence of deepwater gas hydrates and, in particular, the type of sediment in which gas hydrate forms. By assessing the in situ occurrence of gas hydrate in over 1700 industry wells, this research will directly identify methane hydrate resources, and may identify new potentially commercial hydrate-bearing sand reservoirs. In addition, approximately 200 of the 1700 industry wells were drilled at water column depths of 500–600 meters, which are most sensitive to warming temperatures at the ocean bottom or decreases in sea level. Understanding the distribution and concentration of hydrate in these shallow waters is important for understanding the response of gas hydrate over geologic time.

Accomplishments
New project awarded on October 1, 2012

Current Status (November 2012)
In the initial phase of the project, researchers will use ArcGIS to calculate the depth of the GHSZ throughout the Gulf of Mexico. The resulting data will then be used to order approximately 1700 industry well logs produced for wells penetrating the GHSZ. The logs will then be evaluated to determine the presence of gas hydrate, and a database of parameters relevant to gas hydrate occurrence will be established for each well. True resistivity models will be developed for the hydrate-bearing sand reservoirs of two JIP Leg II wells (WR313-G and GC955-H). The true formation resistivities determined through this process will be used to calculate hydrate saturation.

Project Start: October 1, 2012
Project End: September 30, 2015

Project Cost Information:
Phase 1 - DOE Contribution: $149,706, Performer Contribution: $52,500
Phase 2 - DOE Contribution: $136,506, Performer Contribution: $22,000
Planned Total Funding - DOE Contribution: $286,212, Performer Contribution: $74,500

Contact Information:
NETL – Skip Pratt (skip.pratt@netl.doe.gov or 304-285-4396)
The Ohio State University – Ann Cook (cook.1129@osu.edu or 614-247-6085)
If you are unable to reach the above personnel, please contact the content manager.