MMS ENVIRONMENTAL STUDIES PROGRAM:  ONGOING STUDIES

MMS OCS Region:

Gulf of Mexico

Title:

Improving the Predictive Capability of 3D Seismic Surface Amplitude Data for Identifying Chemosynthetic Community Sites (GM-92-42-76)

Planning Area:

Central

Total Cost:  $799,000

Period of Performance:  FY 2000-2008

Conducting Organization:

MMS Contact:

Description:

Background:  Minerals Management Service is responsible for protecting sensitive biological communities on the Outer Continental Shelf from destruction by oil and gas activities. Exploration and development plans are reviewed to determine whether activities are within close proximity to sensitive communities. The location of the community is often determined from surface seismic data since most communities are located on relatively hard surfaces which result in a different response than surrounding sediments during the collection of seismic data. In particular, the unique chemosynthetic communities found in the Gulf of Mexico are associated with outcrops of gas hydrate, which forms a hard surface and therefore can be identified from seismic data. The data, however, is open to interpretation and may result in mitigations being applied to areas where there are no sensitive communities.

Minerals Management Service has access to all the seismic data collected from the Gulf of Mexico, which is not available to any other single entity. Recently, surface seismic data and underlying geologic structures have been synthesized for a more complete interpretation. However, this data will needs further groundtruthing to verify that the geologic criteria are interpreted correctly.

This study involves a joint effort between MMS personnel in the Resource Evaluation Section, Field Operations, and Leasing and Environment with an LSU investigator. The seismic information will be interpreted by both MMS and LSU personnel and further investigated by visual confirmation using a submarine for shallow depths and an ROV for greater depths. The results will be used to better interpret seismic data and fine tune mitigations during reviews of chemosynthetic community locations.

Objectives:  The objectives of this study are to define criteria for the surface expressions of hydrates and to verify that the criteria are valid.

Methods:  Minerals Management Service and LSU personnel will review and interpret in house seismic data to identify sites where hydrates are expected as well as sites where they are not and develop geologic criteria these sites. A submarine will be used to investigate sites that are less than 1000 m., while an ROV will be used to visit sites at greater depths. The visual observations will be synthesized with the geologic criteria to better define interpretations of data submitted in plans and application of mitigations.

Products:  A final report, pictures, and videos of the locations investigated.

Importance to MMS:  The MMS has historically provided protection from impacts to physically and biologically sensitive offshore bottom features, such as chemosynthetic communities, by preventing activities within a defined distance of the bottom feature. Information from this study will be useful in better interpreting data supplied by offshore operators to establish zones of no activity.

Current Status:  A final cruise using an ROV was completed in February 2005, the final report is in preparation.

Final Report Due:

December 2007

Publications:

Chen, D.F., L.M. Cathles, III, and H.H. Roberts, (2004), The geochemical signatures of variable gas venting at gas hydrate sites: marine and Petroleum Geology, v. 21, p. 317-326.

Sassen, R., H.H. Roberts, R. Carney, A.V. Milkov, D.A. DeFreitas, B. Lanoil, C. Zhang, (2004), Free hydrocarbon gas, gas hydrate, and authigenic minerals in chemosynthetic communities of the northern Gulf of Mexico continental slope: relation to microbial processes. Chemical Geology, v. 205, p. 195-217.

Sassen, R., A.V. Milkov, H.H. Roberts, S.T. Sweet, and D.A. DeFreitas, (2003), Geochemical evidence of rapid hydrocarbon venting from a seafloor-piercing mud diapir, Gulf of Mexico continental shelf: Marine Geology, v. 198, p. 319-329.

Rogers, R.E., J.L. Dearman, and H.H. Roberts, (2003), Enhancement of gas hydrate formation in Gulf of Mexico sediments: Proceedings, Offshore Technology Conference, OTC 15393, p. 1-7.

Roberts, H.H., J.L. Hunt, W.W. Shedd, and R. Sassen, (2002), Surficial gas hydrates, part of the fluid and gas expulsion response spectrum: Identification from 3D seismic data: Proceedings Offshore Technology Conference, OTC 14033, May 6-9, 2002, p. 1-10.

Roberts, H.H., R. Sassen, and A.V. Milkov (2001) Seafloor expression of fluid and gas expulsion from deep petroleum systems, continental slope of the northern Gulf of Mexico: 2001 GCSSEPM research Foundation, 21^st Ann. Res. Conf., Petroleum Systems of Deep-Water Basin, p. 407-421.

Roberts, H.H., (2001), Fluid and gas expulsion on the northern Gulf of Mexico continental slope: Mud-prone to mineral-prone responses. In: C.K. Paull and W.P. Dillon (eds.), Natural gas hydrates: Occurrences, distribution, and dynamics: American Geophysical Union, Geophysical Monograph, No. 124, p. 145-161.

Sassen, R., H.H. Roberts, A.V. Milkov, and D.A. DeFreita (2001) Seafloor vents, seeps, gas hydrate: Relation to flux rate from the deep Gulf of Mexico petroleum system: 2001 GCSSEPM Research Foundation, 21^st Ann. Res. Conf., Petroleum Systems of Deep-Water Basins, p. 489-505.

Roberts, H.H., J.M. Coleman, J. Hunt, Jr., and W.W. Shedd, (2000), 3D-seismic surface amplitude mapping for unproved interpretation of seafloor geology and biology: Offshore Magazine, September Issue, p. 126-128, 181.

Roberts, H.H., J.M. Coleman, J. Hunt, Jr., and W.W. Shedd, (2000), Surface amplitude mapping of 3D-seismic for improved interpretations of seafloor geology and biology from remotely sensed data: Transactions Gulf Coast Association of Geological Societies, v. 50, p. 495-504.

Roberts, H.H., J.L. Hunt, Jr., and W. Shedd, 2005, Seafloor and subsurface geology of gas hydrate sites—northern Gulf of Mexico continental slope: SGS Geophysical Symposium, New Orleans, LA, June 9 (Poster).

Roberts, H.H., 2004, Gas hydrates in the Gulf of Mexico’s complex geologic setting: Future resource or just another geohazard? Houston Geological Society, Houston, TX, April 28, (Invited Talk).

Roberts, H.H., J.M. Coleman, J.L. Hunt, Jr., W.W. Shedd, and R. Sassen, 2003, Seafloor and subsurface geology of gas hydrate exposure sites-Northern Gulf of Mexico Continental Slope: American Association of Petroleum Geologists Annual Meeting, Official Abstract Volume, p. A146 (Poster).

Roberts, H.H. and J.M. Coleman, 2003, Improving the predicitive capability of 3D-seismic surface amplitude data for identifying chemosynthetic communities: MMS-Information Transfer Meeting, Jan. 14-16, New Orleans, LA. (Talk).

Roberts, H.H., J.M. Coleman, and H. Peele, 2003, Mapping areas of hard bottom and other important bottom types-outer continental shelf and upper continental slope (northern Gulf of Mexico): MMS-Information Transfer Meeting, Jan. 14-16, New Orleans, LA. (Talk).

Sassen R., H.H. Roberts, J.P. Chanton, A.V. Milkov, D.A. DeFreitas, and S.T. Sweet, 2003, Evidence of a deep source of bacterial methane in the Gulf of Mexico continental slope: American Chemical Society Meeting, New Orleans (Talk)

Roberts, H.H., J.L. Hunt, W.W. Shedd, and R. Sassen, 2002, Surficial gas hydrates, part of the fluid and gas expulsion response spectrum: Identification from 3D seismic data: 2002 Offshore Technology Conference, OTC 14033, 10 p.

Roberts, H.H., J.M. Coleman, J.L. Hunt, W.W. Shedd, R. Sassen, and A. Milkov, 2002, Gas hydrate deposits in a complex geologic setting northern Gulf of Mexico slope: Gulf Coast Association of Geological Societies Annual Convention, October 30 – November 1, Austin, TX., Official Program, p. 101 (Poster).

Roberts, H.H., 2002, Geologic and biologic responses to varying rates of fluid and gas expulsion – Northern Gulf of Mexico, American Association of Petroleum Geologists Hedberg Conference, Vanconver, April 7-10, 2002 (Talk).

Roberts, H.H., J.M. Coleman, J.L. Hunt, W.W. Shedd, A.V. Milkov, and R. Sassen, 2002, Fluid and gas expulsion on the continental slope, northern Gulf of Mexico: 2001 GCSSEPM Research Foundation, 21^st Ann. Res. Conf., Petroleum Systems of Deep-Water Basin, (Poster).

Roberts, H.H., J.L. Hunt, W.W. Shedd, and R. Sassen, 2002, Surficial gas hydrates, part of the fluid and gas expulsion response spectrum: Identification from 3D-seismic: Proceedings Offshore Technology Conference, OTC 14033, May 6-9, 2002, p. 1-10, (Talk).

Roberts, H.H., J.M. Coleman, J.L. Hunt, W.W. Shedd, R. Sassen, and A. Milkov, 2002, Gas hydrate deposits in a complex geologic province (GOM): Linkage to fluid-gas expulsion: Gulf Coast Association of Geological Societies Annual Convention, Austin, TX, (Poster).

Sassen, R., A.V. Milkov, D.A. DeFreitas, and H.H. Roberts, 2002, Gas venting and gas hydrate stability in the northwestern Gulf of Mexico-significance to sediment deformation: Proceedings Offshore Technology Conference, OTC 14034, May 6-9, 2002, p 1-7, (Talk).

Roberts, H.H., J.M. Coleman, J.L. Hunt, W.W. Shedd, A.V. Milkov, and R. Sassen, 2001, Gas hydrates in a complex geologic province, Northern Gulf of Mexico: AAPG Annual Convention, Official Program, v. 10, p. A170, (Poster).

Roberts, H.H., 2001, A new source of energy from deep water – The potential of gas hydrates: Lafayette Geological Society, November 28, 2001 (Talk).

Roberts, H.H., 2001, Gas hydrates – Can they be produced from the Gulf of Mexico slope? Society of Independent Professional Earth Scientists (SIPES), April 17, 2001. (Invited Talk)

Roberts, H.H., J.M. Coleman, J.L. Hunt Jr., W.W. Shedd, A.V. Milkov, and R. Sassen, 2001, Gas hydrates in a complex geologic province, northern Gulf of Mexico: American Association of Petroleum Geologists Annual convention, Denver, Co., May 2-6, 2001. (Invited Poster).

Roberts, H.H., J.M. Coleman, J.L. Hunt, W.W. Shedd, A.V. Milkov, and R. Sassen, (Accepted), Gas hydrates in a complex geologic province, northern Gulf of Mexico: American Association of Petroleum Geologists Convention, Denver, CO., June 3-6, 2001, Abst. (Poster).

Sassen, R., S.T. Sweet, A.V. Milkov, D.A. DeFreitas, and H.H. Roberts, Thermogenic gas venting and gas hydrate in the Gulf of Mexico potential significance to climate change: American Association of Petroleum Geologists Convention, Denver, CO., June 3-6, 2001, Abst. (Poster).

Sassen, R., S.T. Sweet, A.V. Milkov, D.A. DeFreitas, and H.H. Roberts, 2001, Thermogenic gas venting and gas hydrate in the Gulf of Mexico-potential significance to climate change: American Association of Petroleum Geologists Annual Convention, Denver, Co, May 2-6, 2001. (Poster).

Roberts, H.H., J. Coleman, J. Hunt Jr., and W. Shedd, 2000, Surface amplitude mapping of 3D-seismic data for improved interpretations of seafloor geology and biology from remotely sensed data: 50^th Annual Gulf Coast Association of Geological Societies convention, October 25-27, 2000. (Talk).

Roberts, H.H., 2000, Fluid and gas expulsion on the northern Gulf of Mexico slope: American Association of Petroleum Geologists Annual Convention, April 16-19, New Orleans, LA., Program and Abstracts, p. A126. (Talk).

Roberts, H.H., Wm. J. Wiseman, Jr., J. Hooper, and G. Humphrey, 2000, Gas hydrate at or near the modern seafloor: Effects of water column temperature variations on hydrate stability: American Association of Petroleum Geologists Annual Convention, April 16-19, New Orleans, LA., Program and Abstracts, p. A126. (Talk).

Sassen, R., H.H. Roberts, and A.V. Milkov, 2000, Oil and gas fields, seafloor vents, seeps, and gas hydrate deposits as products of the Gulf of Mexico Petroleum System: 20^th Annual GCSSEPM Research Conference, Deep Water Petroleum System, Houston, Texas, December 2-5, 2001, Abst. (Talk).

Roberts, H.H., R. Sassen, and A.V. Milkov, 2000, Seafloor expressions of fluid and gas expulsion from deep petroleum systems, continental slope of the northern Gulf of Mexico: 20^th Annual GCSSEPM Research Conference, Deep Water Petroleum Systems, Houston Texas, December 2-5, 2001.

Roberts, H.H., 2000, Fluid and gas expulsion on the northern Gulf of Mexico continental slope: Mud-prone to mineral-prone responses: American Geophysical Union, Fall Meeting, San Francisco, CA., Abst. (Talk).

Affiliated WWW Sites:

Coastal Marine Institute

Revised date:

July 2007

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