Integrating 3-D Seismic Attributes and Well Logs for Mapping Bypassed Reservoir and Meandering Fluvial Architecture, Stratton and Agua Dulce Fields, Texas Gulf Coast, USA

By

Hamed Zeidan El-Mowafy¹, Dennis R. Kerr¹, Christopher L. Liner¹

(1) The University of Tulsa, Tulsa, OK

 A study of the basal section of the Oligocene middle Frio Formation in Stratton and Agua Dulce fields tests the effect of synthetic and antithetic growth faults on the fluvial architecture. Gross- and net-sand thickness maps, log facies maps, and well-log cross-sections define channel belts. Correlation analysis confirms that seismic amplitude delineates the lateral extent of channel-fill deposits. RMS amplitude anomaly maps of the F11 interval show that meandering features relate to net pay and hydrocarbon pore volume thickness.

Bypassed reservoir is indicated from the 3D seismic mapping. This reservoir is a potential candidate for infield reserve growth in the northern Stratton area.

This area is dominated by the major Vicksburg and Agua Dulce growth faults, along with several synthetic and antithetic faults. Seismic and well log analysis show that subsidiary faults displace the stratigraphic units into several discrete compartments and result in different stacking patterns of the fluvial channel-fill deposits. The F11 reservoir unit is made up of several meandering channel belts. A broad northwest-southeast valley-fill, up to 4300 ft width, in the footwall block is controlled by the Agua Dulce fault at its southern boundary. In the hanging wall block, a wide avulsion complex is made up of east-west trending narrow meander channel-belts that are up to 1980 ft wide. In the southern part of the field, broad northwest-southeast meander channel belts are present in the hanging wall block. Post-depositional faulting along crestal-collapse antithetic faults offset these channel belts.