Reservoir Characterization of a Permian Deep-Water Sandstone
East Ford Field, Bell Canyon Formation, Delaware Basin, Texas

Shirley P. Dutton, Ph.D.

ABSTRACT
Deep-water sandstones of the Delaware Mountain Group in west Texas and southeast New Mexico contained an estimated 1.8 Bbbl of original oil in place. Primary production from these fields is commonly less than 15%, and secondary waterfloods recover only an additional 45% OOIP. East Ford field, a Delaware Sandstone field that produces from the Ramsey sandstone in the upper Bell Canyon Formation, went directly from primary production to tertiary recovery by CO2 flooding. CO2 injection began in July 1995, and production response was observed in December 1997. Field production has increased from 30 bbl/day to more than 185 bbl/day. Oil recovery has been improved by the CO2 flood, but not as much as expected. Geologic heterogeneities are apparently influencing reservoir displacement operations in the East Ford unit.

  A depositional model of the unit was developed using data from Bell Canyon outcrops and subsurface data from East Ford and the adjacent Ford Geraldine unit. The Ramsey sandstones were deposited by turbidity currents in a basin-floor setting. The sandstones are interpreted as having been deposited in a channel-levee system that terminated in broad lobes; overbank splays filled topographically low interchannel areas. Porosity and permeability of the reservoir sandstones are controlled by calcite cement concentrated in layers from 2 to 16 inches thick. Injector wells located in splay sandstones apparently have poor communication with wells in channel sandstones, perhaps because communication is restricted through levee and channel-margin deposits. Modification of the alignment of injectors and producers may overcome the problem of apparently restricted communication between wells in splay and channel sandstones.

 

Bureau of Economic Geology, The University of Texas at Austin, Austin, TX ; Telephone: (512) 471-0329
E-mail: shirley.dutton@beg.utexas.edu