High Resolution Processing of Seismic Data from GB 424 and 425 and MC 852 and 853, Gulf of Mexico  

DE-AF26-01NT00370

Goal
The goal of the project is to better characterize potential methane hydrate drilling sites in the Gulf of Mexico for the Ocean Drilling Program.

Performer
Western-Geco – data and processing

Location
Denver, Colorado 80202

Background
WesternGeco retrieved existing raw data from archived field tapes and performed 3D high-resolution processing of seismic data from Garden Banks Blocks 424 and 425, and Mississippi Canyon Blocks 852 and 853, in the Gulf of Mexico. The performer optimized the image quality by utilizing data recorded by the near-offset hydrophone groups and using high frequency data to obtain improved resolution of near-surface features.

Project Impact
The project had an impact on the Ocean Drilling Program’s decisions related to hydrate research wells in the Gulf of Mexico. The project provided improved site characterization information for Green Canyon and Mississippi Canyon sites that had been proposed for drilling. However, based in part on the improved seismic images, these sites were not selected for drilling.

Accomplishments

• Completed the first part of the processing sequence which included: performing SEG-D conversion to Western Format, tracing select offset range and applying debias filter, merging seismic with navigation, correcting for spherical divergence, editing traces, performing minimum phase signature deconvolution and spiking deconvolution or constant “Q,” and

• Completed the second stage of the processing sequence which included: surface consistent amplitude compensation, 3D binning to remove redundant offsets (max fold of 6 per cell), sorting to CMP, trimming statics to correct for water velocity differences, NMO correction (using original velocity field), stacking (13.3m by 53.3 m stacking grid), trace interpolation to fill missing traces, 3D trace interpolation to a 26.6m cross line spacing, 3D RNA (FX decon), 3D time migration (using the F-K extended stolt migration), additional whitening, 3D time-variant/spatially variant RAC, acquisition footprint attenuation, time variant filtering, application of datum correction to sea level, and copying the final migration volume to SEG-Y.

This work was considered sole source to Western-Geco because they own the proprietary data and have specialized experience in 3D high-resolution seismic data processing to achieve the required spatial resolution.

Current Status
The work was completed and all deliverables received. These included a Final Report on the Processing, Final stack volumes and final migration volumes in SEG-Y format, bin center tapes and maps for both Garden Banks Blocks 424 & 425 and Mississippi Canyon Blocks 852 & 853.

Project Start: April 17, 2001
Project End: July 30, 2001

DOE Contribution: $32,000
Performer Contribution: $0

Contact Information:
NETL – Frances Toro (frances.toro@netl.doe.gov or 304-285-4107)
Western-Geco – J. Larry Cain (303-629-9250)

Final Report [PDF-2789KB] - July, 2001 - 3-D High Resolution Short Offset Processing, Garden Banks IIB and Mississippi Canyon I