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SWLGS Luncheon Topics

Updated August 05, 2003

May 2001

Geologic Overview of the NE Mississippi Fan & Shelf - West Florida Terrace Region, Offshore GOM
Norman Biles, Schlumberger Western Geco


Abstract Summary: This study is based on the joint venture (Schlumberger and TGS NOPEC) Phase 46, 16,000-line-mile 2D seismic and gravity/magnetic program that was acquired, processed, and interpreted from 1997-1999. It consists of  2 x 2 mile grid (16,100 mi2), covering parts of Main Pass, Destin Dome, Viosca Knoll, Mississippi Canyon, Desoto Canyon, Atwater Valley, and Lloyd Ridge. Water depths range from 75 feet to over 10000 feet. Geological control from 44 biostratigraphy wells helped calibrate seven mapped horizons. In addition, a velocity cube was generated from this dataset. A Cretaceous carbonate shelf, a prominent escarpment to the southeast, dominates the east and northeast portions of the survey. It is overlain by primarily regressive Cenozoic clastics. West of the carbonate shelf is a Miocene to Plio-Pleistocene shelf /slope/fan complex. The shelf facies is developed in the northwest and progresses through slope to deepwater fan deposits toward the southeast. This complex contains numerous allochthonous salt bodies. In general, autochthonous salt structures are present east of the detached salt, underlying the slope fan complex. These continue eastward to the Cretaceous shelf edge. This region is becoming an increasingly attractive area to explore. For example, "Crazy Horse" in Mississippi Canyon (MC) Block 778 is a recent subsalt discovery within the study area.

Biographical Sketch: Norman E. Biles received a BS in physics from Lewis and Clark College, and an MS (1966) in geophysics from New Mexico Tech. He worked for Phillips Petroleum from 1966 to 1988 in data processing and international/domestic exploration. Consulted for BP and TGS on GOM lease sales and velocity interpretation from 1988 to 1990. Since 1990 he has been involved with velocity studies and seismic interpretation at WesternGeco (previously Schlumberger Geco-Prakla). Recent seismic interpretation assignments include the eastern Gulf of Mexico and deepwater Brazil. He is a member of the SEG and Houston's geologic and geophysical societies.