The stratigraphic complexity of the Plio-Pleistocene reservoir sands in the East Breaks 165 field (offshore Texas) is readily demonstrated after the completion of exploration and development drilling. Two main problems recurring during field development involved: (1) prediction of turbidite sand facies distributions and thickness, and (2) identification of fault offsets in the high variable reservoir sands. The well control and a 3D seismic data set provide the basis for reservoir description and a deepwater sand depositional model in the East Breaks 165 area.
Four main productive sand intervals are present in the Plio-Pleistocene section. All are characterized by rapid lateral thickness and facies changes. Sand packages are composed of both clean, blocky, channel facies and fining-upward channel levee/overbank facies. The channel systems developed within an intraslope basin. Lateral migration of turbidite channel systems within the basin resulted in sand thickness variations of up to 50 ft over horizontal distances of less than 250 ft.
The main reservoir structure is a highly faulted anticline located downthrown to northeast-trending extensional faults with up to 2500 ft of displacement. The faulting is a result of structural collapse owing to salt withdrawal from a salt-cored anticlinal ridge. Numerous small-scale faults that juxtapose permeable and impermeable units have added further complexity to the field development.
The refined turbidite channel and channel levee/overbank model has been important in delineating future recompletion and development targets in the East Breaks 165 field. This model should also prove to be a useful analog for future Gulf of Mexico deepwater exploration and development programs.
AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)