Facies architecture and reservoir compartmentalization in the McAllen Ranch gas field, Hidalgo County, Texas

Conference · Tue May 01 04:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:6663719

Langford, R P; Wermund, E G; Zinke, S G; Guevara, E H; Finley, R J; Brewton, J G ^[1]

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1. Univ. of Texas, Austin (USA)

McAllen Ranch field is typical of south Texas gas fields producing from the overpressured sandstone reservoirs in the Oligocene Vicksburg Formation. As part of an effort funded by the Gas Research Institute, the US Department of Energy, and the state of Texas, and with the cooperation of Shell Oil Company, the depositional and diagenetic reservoir heterogeneities of the field were studied as a means of detecting uncontacted and bypassed gas pools. McAllen Ranch field consists of faulted, shingled, southeastward-tapering wedges that overlie a basal decollement between the Vicksburg Formation and underlying shales of the Jackson Group. Deposition was contemporaneous with deformation, resulting in a complex interplay between sedimentation and tectonism. Gas production is from multiple depositionally similar sandstone packages within the lower Vicksburg. Each package contains stacked, upward-coarsening intervals deposited by a prograding shelf-edge delta. The S sandstone, consisting of five stacked progradational intervals, is the richest reservoir, accounting for over 50% of gas production. Reservoir heterogeneity is present at four different scales. (1) Individual delta lobes are strike elongate 3.5 {times} 7 mi (5.6 {times} 11.2 km). (2) Within each lobe, depocenters commonly less than 1.5 mi (2.7 km) in diameter contain stacked distributary channels and associated delta-front facies. These depocenters often are aligned with faults. (3) Individual distributary channels are 1,000-3,000 ft (300-8,900 m) wide and 10-30 ft (3-10 m) thick. (4) Zones 1-2 ft (0.3-0.6 m) thick within the coarsest grained distributary channel and delta-front facies are the most permeable (1-10 md). Offset vertical seismic profile data were used to resolve strata within which seismic and well log correlations exhibit significant thinning.

• OSTI ID: 6663719
• Report Number(s): CONF-900605--
• Conference Information: Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Journal Volume: 74:5
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
030200* -- Natural Gas-- Reserves
Geology
& Exploration
58 GEOSCIENCES
580000 -- Geosciences
CENOZOIC ERA
DIAGENESIS
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC FORMATIONS
MINERAL RESOURCES
NATURAL GAS DEPOSITS
NATURAL GAS FIELDS
NORTH AMERICA
PERMEABILITY
RESERVOIR ROCK
RESOURCES
ROCKS
SANDSTONES
SEDIMENTARY ROCKS
TERTIARY PERIOD
TEXAS
USA