Reservoir heterogeneity in the middle Frio Formation: Case studies in Stratton and Agua Dulce fields, Nueces County, Texas

Conference · Sat Sep 01 00:00:00 EDT 1990 · AAPG Bulletin (American Association of Petroleum Geologists); (USA)

OSTI ID:5965199

Kerr, D R ^[1]

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1. Univ. of Texas, Austin (USA)

Selected middle Frio (Oligocene) reservoirs of Stratton field and the contiguous Agua Dulce field are being studied as part of a Gas Research Institute/Department of Energy/State of Texas cosponsored program designed to improve reserve growth in mature gas fields. Over the past four decades, Stratton has produced 2.0 tcf of gas from 113 middle Frio reservoirs, and Agua Dulce has produced 1.6 tcf from 116 reservoirs. Recent drilling and workover activities, however, suggest the presence of additional untapped or bypassed middle Frio reservoirs. Four reservoirs, the E18/6,020-ft, E21/6,050-ft, E31/6,100-ft, and E41/Bertram, were evaluated over a 13,000-acre tract that includes areas adjacent to both fields. The middle Frio is composed of sand-rich channel-fill and splay deposits interstratified with floodplain mudstones, all forming part of the Gueydan fluvial system. Channel-fill deposits are 30 ({plus minus}15) ft thick and 2,500 ({plus minus}500) ft wide. Splay deposits are up to 30 ft thick proximal to channels and extend as much as 2 mi from channels. Channel-fill and associated splay sandstones are reservoir facies (porosity 20%; permeability = 10s to 100s md); floodplain mudstones and levee sandy mudstones are barriers to flow facies separating individual reservoirs vertically and laterally. The E41/Bertram reservoir is an example of a laterally stacked channel system deposited during relatively slow aggradation. This reservoir includes sand-on-sand contacts and is composed of mostly leaky compartments. The E 18/6,020-ft, E21/6,050-ft, and E31/6,100ft reservoirs are examples of vertically stacked channel systems reflecting higher rates of aggradation. Vertically stacked architectures are more favorable for isolated compartments and therefore are better candidates for infield reserve growth.

• OSTI ID: 5965199
• Report Number(s): CONF-9010204-; CODEN: AABUD
• Journal Information: AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 74:9; Conference: Gulf Coast Association of Geological Societies and Gulf Coast Section of SEPM (Society of Economics, Paleontologists, and Mineralogist) meeting, Lafayette, LA (USA), 17-19 Oct 1990; ISSN 0149-1423
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
58 GEOSCIENCES
NATURAL GAS DEPOSITS
RESERVOIR ROCK
TEXAS
GEOLOGIC FORMATIONS
GEOLOGIC TRAPS
SANDSTONES
TERTIARY PERIOD
WELL DRILLING
CENOZOIC ERA
DRILLING
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGIC DEPOSITS
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NORTH AMERICA
RESOURCES
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USA
030200* - Natural Gas- Reserves
Geology
& Exploration
580000 - Geosciences