Abstract: 3D Exploitation of Nod Mex Reservoirs in Phase Four Field, Wharton County, Texas
MARK D. McCUEN, and MARK A. WEST
Cox & Perkins
Exploration, Inc., Houston, TX
Phase Four field is located in the "Expanded" or "Downdip" Yegua trend in south-central Texas, where reservoirs are developed within the lowstand systems tracts of at least six high-frequency type-one sequences. Phase Four Field is actually a complex of multiple small isolated reservoirs (<200 acres), which are stratigraphically and structurally compartmentalized. Shelf-edge deltaic sand lowstand prograding complexes provide the reservoirs in the Phase Four field complex. These deltaic sands display extreme lateral variations in thickness. Incised valley feeders channeled sediment across the shelf and formed distributary channel complexes within the lower reaches of the valley mouths at the faulted shelf edge.
Field development of Phase Four Field was difficult due to the ineffectiveness
of the 2D seismic data in imaging the complex stratigraphy and faulting.
Approximately 30 square mi of 3D data was acquired in the Phase Four field
area. In addition to the full offset, DMO
migrated volume; near-offset,
mid-offset, and far-offset migrated volumes were created for AVO interpretation.
A comparison of pre- and post 3D interpretations and 2D versus 3D seismic
show the effectiveness of the 3D seismic and the 3D AVO method in rapidly
analyzing the existing and potential reservoirs. Test wells were targeted
in the optimum parts of the reservoirs, resulting in higher sustained rates
and quicker payouts. The 19 wells drilled based on interpretation of the
3D data yielded a 79% commercial success rate versus 24% from 21 wells
drilled prior to the 3D survey.
AAPG Search and Discovery Article #90932©1998 GCAGS/GCS-SEPM Meeting, Corpus Christi, Texas