Engineers, Inc.
A 10-acre infill pilot test was conducted in the Denver Unit of the Wasson San Andres Field of West Texas to determine if the Unit could be further infilled economically to a tighter spacing at the culmination of a 20-acre infill program. Primary objectives of the test were to (a) delineate pay discontinuity in this San Andres dolomite reservoir, (b) determine size, shape, and orientation of waterflood fronts, (c) determine oil productivity of potential 10-acre locations, and productivity of potential 10-acre locations, and (d) evaluate remaining oil saturation.
From the results of the three-well program, it was concluded that the pay program, it was concluded that the pay continuity is higher than had been interpreted from previous work. All productive zones within the pay interval are being flooded, although at different rates such that 10-acre locations do not appear to have sufficient economic potential to support further infilling. From test data, a preferential directional conductivity could not be ascertained. The results of several methods of investigating residual oil saturation (well bore logs, whole core analysis, laboratory core centrifuge, counter current imbibition tests, and laboratory waterflood susceptibility tests) are discussed.
A previous paper has discussed the changing concepts in the Denver Unit carbonate waterflooding with respect to geology, reservoir engineering, injection and production, and development (20-acre infill drilling). Subsequently, a 10-acre infill pilot test was carried out to determine if the Unit could be further infilled economically at the culmination of the 20-acre infill program. Primary objectives of the test were to (a) delineate Primary objectives of the test were to (a) delineate pay continuity at closer well spacing, (b) pay continuity at closer well spacing, (b) determine size, shape and orientation of waterflood fronts, (c) determine oil productivity of potential 10-acre locations, and productivity of potential 10-acre locations, and (d) evaluate remaining oil saturation to waterflooding.
