Frio Formation of the Texas Gulf Coast Basin: Depositional Systems, Structural Framework, and Hydrocarbon Origin

RI0122. Frio Formation of the Texas Gulf Coast Basin--Depositional Systems, Structural Framework, and Hydrocarbon Origin, Migration, Distribution, and Exploration Potential, by W. E. Galloway, D. K. Hobday, and K. Magara, assisted by Diana Morton, Mark Helper, Victor Gavenda, and Nathan Smith. 78 p., 76 figs., 15 tables, 19 plates, 1982. ISSN: 0082335X: Print.

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ABSTRACT
The Frio Formation is one of the major Tertiary progradational wedges of the Texas Gulf Coast Basin and has yielded nearly 6 billion bbl of oil and 60trillion ft30f gas. The Frio and its updip equivalent, the Catahoula Formation, consist of deposits of two large fluvial and associated deltaic systems centered in the Houston and Rio Grande Embayments. Structures in the Houston Embayment are dominated by syndepositional deformation of underlying Jurassic salt. Mobilization of thick, undercompacted prodelta and slope muds characterized the tectonic evolution of the deltaic sequence in the Rio Grande Embayment. These two major deltaic depocenters are separated by a vertically stacked, strike-parallel barrier and strandplain system.

Underlying, interbedded, and transgressive shelf, prodelta, and continental slope mudstone sequences provide principal source and sealing facies. Sparse organic geochemical data and regional thermal and compaction-history analyses show that large volumes of hydrocarbons have probably been generated within, and effectively expulsed upward and landward from, normally to moderately undercompacted sequences of these rnudstone facies.

All Frio depositional systems contain economically significant, geologically defined hydrocarbon producing plays. Volume, production style, and type of hydrocarbon within each of 10 recognized plays reflect source-rock quality and type, differing compaction and pore-fluid-migration history, and reservoir and trap configurations characteristic of each depositional system. Analysis of volumetric, historical, and geological relationships for production and discovery within each play provides a basis for estimating the undiscovered hydrocarbon resource potential as well as for assigning that potential to specific geographic and stratigraphic subdivisions of the depositional basin.

Keywords: Frio Formation, Gulf Coast Basin, hydrocarbons, oil and gas, Tertiary, Texas

CONTENTS

ABSTRACT

INTRODUCTION

Objectives

Methodology

GEOLOGIC FRAMEWORK

Stratigraphic correlation and relationships

Primary facies mapping

DEPOSITIONAL SYSTEMS

Gueydan fluvial system

Location and boundaries

Facies description

Structural style

Reservoir and trap configurations

Norias delta system

Location and boundaries

Facies description

Structural style

Reservoir and trap configurations

Chita/Corrigan fluvial system

Houston delta system

Location and boundaries

Facies description

Structural style

Reservoir and trap configurations

Buna strandplain/barrier system

Location and boundaries

Facies description

Structural style

Reservoir and trap configurations

Choke Canyon/Flatonia coastal lake/streamplain system

Greta/Carancahua barrier/strandplain system

Location and boundaries

Facies description

Structural style

Reservoir and trap configurations

Anahuac Shale wedge

Frio depositional history

Comparison of Frio and late Pleistocene paleogeography

Statistical characterization of facies assemblages

Thicknesses of sandstone and shale units

Number of sandstone and shale units

Sandstone percentage

Summary

HYDROCARBON SOURCE, MATURATION, MIGRATION, AND ENTRAPMENT

Concentration of organic carbon in shales

Maturation and expulsion of generated hydrocarbons

Effective hydrocarbon expulsion from source rocks

Expulsion and movement of compaction water and hydrocarbons

Source, reservoir, and primary migration

HYDROCARBON PRODUCTION

Play recognition and description

Play stratigraphy, structural relationships, and hydrocarbon production

EVALUATIONS OF REMAINING RESOURCE POTENTIAL

Historical approach

Cumulative number of exploratory wells

Cumulative footage of exploratory drilling

Discovery versus time

Comparative results

Volumetric approach

Source and migration potential approach

CONCLUSIONS

ACKNOWLEDGMENTS

REFERENCES

76 Figures

15 TABLES

1. Statistics (in feet) of sandstone-unit and shale-unit thickness

2. Number of sandstone (or shale) units normalized for 1,000-lt (300-m) intervals

3. Sandstone-percentage statistics

4. Defining geologic and exploration attributes of Frio MSU plays

5. Quantitative geologic attributes of Frio MSU plays

6. Hydrocarbon inventory for Frio MSU plays

7. Statistical summary of recoverable oil (cumulative-well-number method)

8. Statistical summary of recoverable gas (cumulative-well-number method)

9. Statistical summary of total number, footage, and average depth of exploratory wells, 1942-1977

10. Statistical summary of recoverable oil (cumulative-footage method)

11. Statistical summary of recoverable gas (cumulative-footage method)

12. Statistical summary of recoverable oil (discovery-versus-time method)

13. Statistical summary of recoverable gas (discovery-versus-time method)

14. Summary of estimates of future discoveries, Frio MSU, derived from historical projections

15. Volumetric estimations of undiscovered hydrocarbons in plays of the Frio MSU

19 PLATES (accompanying book)

1. Regional correlation sections and depositional subbasins

2. Top of Frio structure map

3. Frio MSU isopach map

4. Net-sandstone isolith map, upper Frio operational unit

5. Net-sandstone isolith map, middle Frio operational unit

6. Net-sandstone isolith map, lower Frio operational unit

7. Sandstone-percentage map, upper Frio operational unit

8. Sandstone-percentage map, middle Frio operational unit

9. Sandstone-percentage map, lower Frio operational unit

10. Log facies map, upper Frio operational unit

11. Log facies map, middle Frio operational unit

12. Log facies map, lower Frio operational unit

13. Frio depositional systems

14. Stratigraphic dip section 1-1'

15. Stratigraphic dip section 6-6'

16. Stratigraphic dip section 13-13'

17. Stratigraphic dip section 17-17'

18. Stratigraphic dip section 22-22'

19. Map of Frio petroleum fields and outline of plays


Citation
Galloway, W. E., Hobday, D. K., Magara, K., and others, 1982, Frio Formation of the Texas Gulf Coast Basin--Depositional Systems, Structural Framework, and Hydrocarbon Origin, Migration, Distribution, and Exploration Potential: The University of Texas at Austin, Bureau of Economic Geology, Report of Investigations No. 122, 78 p.