Martin K. Dubois1, Alan P. Byrnes1, W. Lynn Watney1
(1) Kansas Geological Survey, University of Kansas, Lawrence, KS
ABSTRACT: Field Development and Renewed Reservoir Characterization for CO2 Flooding of the Hall-Gurney Field, Central Kansas
Primary and secondary production phases of the seventy-year old Hall-Gurney Field are near completion, however a third development phase could be spurred by a U.S. Department of Energy sponsored Class II carbon dioxide miscible flood demonstration project. The CO2 target reservoirs, Pennsylvanian Lansing-Kansas City (L-KC) Groups, have yielded 90 MMBO of the 152 MMBO cumulative production in the multi-pay field. Primary production, begun in 1931, was followed by extensive waterflooding in the 50's and 60's. Waterfloods reached their economic limits in the 70's and 80's but bi-passed oil represents a significant resource for CO2 miscible flooding, a third development phase.
Reservoir rocks were deposited as coarse-grained ooid sands in shallowing upward fourth order sequences and concentrated on bathymetric highs on the broad Kansas shelf. Subaerial exposure and meteoric water percolation caused ooid dissolution and resulted in oomoldic grainstones. Modern wireline logs and core data from a recently drilled CO2 injection well validate early general reservoir models based on data typical of mid-century development, but also show previously unrecognized reservoir complexity. Detailed reservoir characterization of the 12-18 foot CO2 target zone at the demonstration site indicates the presence of up to three stacked, shallowing-upward cycles contained within a single higher-order shallowing-upward sequence accompanied by vertically increasing porosity and permeability.
In Kansas the L-KC has produced 1.2 billion BO primarily from oomoldic grainstones in 3,500 fields. This case study of a mature field entering its third development phase provides insight into oomoldic limestone reservoirs both in Kansas and worldwide.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado