Gas Hydrates Resource Assessment - Gulf of Mexico OCS Region

Methane Hydrates

The BOEM gas hydrate assessment model was initially developed for the GOM OCS over a period of approximately five years (2003 – 2008). A preliminary assessment of the in-place gas hydrate resources was published in OCS Report MMS 2008-004. This report also included a complete description of the input parameters, methodologies, and modeling approach. The original GOM OCS model structure was modified slightly for the assessment of gas hydrate on the Atlantic and Pacific OCS; the results for all three of these OCS regions are summarized in the “Assessment of In-Place Gas Hydrate Resources of the Lower 48 United States Outer Continental Shelf (BOEM Fact Sheet RED-2012-01).


BOEM Publications

BOEM-FactSheetRED_2012-01Cover

  Assessment of In-Place Gas Hydrate Resources of the Lower 48 United States
Image of MMS Report 2008-004 Publication Cover MMS Report 2008-004
2012 ESRI Publication Image BOEM Presentation at the 2012 ESRI Conference
Gas Hydrates Resource Assessment Map Image ICGH 2011
Image of Alaminos Canyon 21 Site Map Gas Hydrate Joint Industry Project Leg II:
Image of OCS Study BOEMRE 2010-046 Publication Cover OCS Study BOEMRE Report 2010-046
  • Gas Hydrate Resource Potential in the Terrebonne Basin, Northern Gulf of Mexico, 2011, by Frye, M., Shedd, W., and Boswell, R., Marine and Petroleum Geology, Volume 34 Issue 1, June 2012, pages 150-168.

    Abstract - The Terrebonne Basin is a salt-withdrawal mini-basin within the northeast portion of the Walker Ridge protraction area in northern Gulf of Mexico continental slope that contains a thick sequence of upper Pliocene and Pleistocene clastic sediment. Data acquired during the 2009 Gulf of Mexico Gas Hydrate Joint Industry Project Leg II (JIP Leg II) logging-while-drilling (LWD) program confirmed the presence of gas hydrate within a variety of sand and clay units. Integration of the Leg II LWD data with regional seismic mapping allows for the identification of various facies assemblages within the sand units and an initial estimation of the gas hydrate in-place resources throughout the Terrebonne basin. A total of ~4.4 × 109 m3 (1.55 × 1011 ft3) of gas occurs within highly saturated gas hydrate accumulations within channel, proximal levee, and distal levee facies of four primary Lower Pleistocene sand reservoirs. These sand accumulations occur at the base of gas hydrate stability and locally trap additional, unquantified accumulations of free gas. A number of additional thin hydrate-bearing sand units are also observed to occur at shallower depths. Potential recoverable volumes from this accumulation compare favorably with those realized from conventional deep-water gas reservoirs in the vicinity. In addition, Leg II LWD data delineated the occurrence of a stratal-bound occurrence of gas hydrate-filled fractures at low bulk volume saturations within a thick, shallow, and predominantly fine-grained unit. This unit is estimated to contain roughly 17.0 × 109 m3 (5.87 × 1011 ft3) of gas. The areal gas hydrate resource density within the Terrebonne basin is calculated at 1.183 × 109 m3 per km2 where delineated sand reservoirs are present and 0.32 × 109 m3 per km2 where sands are thought to be absent.
  • Occurrence and Nature of “Bottom Simulating Reflectors” in the Northern Gulf of Mexico, 2011, by Shedd, W., Boswell, R., Frye, M., Godfriaux, p, and Kramer, K., Marine and Petroleum Geology, Volume 34 Issue 1, June 2012, pages 4-30.

    Abstract - Subsurface interpretation, utilizing a database of more than 450,000 km2 (175,000 mi2) of three-dimensional (3-D) seismic in the northern Gulf of Mexico (GoM), reveals 145 discrete areas, totaling 4450 km2 (1.1 million acres) where the base of gas hydrate stability (BGHS) can be confidently inferred from seismic data. Unlike many other areas of the world, the majority of these features are not Bottom Simulating Reflectors (BSRs) in the “classic” sense, meaning continuous coherent events that cross-cut primary stratigraphy. Those typical, or continuous BSRs, are noted in only 24% of the features identified within this study. In contrast, the most common seismic manifestation of the BGHS in the GoM (59%) is the discontinuous “BSR”, delineated by widely separated anomalous seismic events that align in general conformance with seafloor bathymetry. A third type of seismic feature, pluming “BSRs”, are continuous events that are not bottom-simulating, but are bowed toward the seafloor and represent areas where large, but areally-limited increases in heat flow (linked to strong vertical fluid flux), perturb the BGHS. The limited nature of continuous BSRs and the relative abundance of discontinuous and pluming forms are attributed to the strong lithologic and structural heterogeneity of the northern GoM basin. This lithologic and structural complexity has served to disrupt and localize regionally pervasive and homogeneous gas flux that is consistent with the formation of large, continuous BSRs noted across other less complex continental margins. The various BSR forms identified in this study are shown to be closely associated (125 of 145) with the occurrence of seafloor amplitude anomalies, which are in turn usually associated with the flanks and crests of salt-cored ridges. These associations are nterpreted to reflect the co-dependence of BSRs and seafloor reflectivity along the migration pathways that typify this geologic setting.