Facies Architecture and Production Characteristics of ... the Frio Formation, Texas. Digital Download

RI0146D. Facies Architecture and Production Characteristics of Strandplain Reservoirs in the Frio Formation, Texas, by Noel Tyler and W. A. Ambrose. 42 p., 29 figs., 1 table, 1985. doi.org/10.23867/RI0146D. Downloadable PDF.


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ABSTRACT
Many modern shore zones comprise a continuum of depositional environments that encompass both strandplain and barrier-island systems. Strandplains are further subdivided into two classes: sand-rich beach-ridge plains and mud-rich chenier plains. Tertiary shorezone systems of the Texas Gulf Coast Basin contain a significant proportion of the Texas oil resource in clastic reservoirs. These reservoirs display better-than-average oil recovery efficiencies. This report describes the production attributes of three Frio strandplain reservoirs--the Cayce, the Cornelius, and the Carlson--in the North Markham-North Bay City field, Matagorda County, Texas.

Hydrocarbons in the North Markham-North Bay City field were trapped in a simple rollover anticline. Oil is produced from stacked strandplain sandstones in this multiple reservoir field. Composite sandstones of beach-ridge plain/distributary/delta-front origin constitute the Cayce oil reservoir. Internal heterogeneity results in considerable fluid-flow anisotropy, as displayed by sequential water-cut maps and oil production maps. Water influx in the strandplain deposits follows broad fronts, whereas water invasion in channel deposits is more restricted and erratic. The Cornelius reservoir was deposited in a system intermediate between sand-rich beach plains and mud-rich chenier plains. Sandy beach ridges, separated by muddy swales, compose the productive framework of this class of strandplain reservoir and furthermore act as conduits for early water influx. Sandstones, possibly of washover origin, in the intervening swales produce oil but are more rapidly drained than are beach-ridge sandstones. The Carlson reservoir produces from transgressed strandplain deposits. Oil is contained in upward-fining transgressive sandstones that rest on thicker but oil-barren progradational facies. Facies analysis indicates that the Carlson had a complex and episodic depositional history, yet water-influx maps and oil production maps suggest isotropic fluid behavior. Modern sand-rich transgressive shore-zone deposits are characteristically sheetlike, as is the transgressive component of the Carlson reservoir. This distinctive morphology appears to have fostered reservoir productivity.

Oil recovery from the North Markham-North Bay City reservoirs follows a predictable trend. Recovery efficiency is highest from the transgressive sheet sands of the Carlson, which is the shallowest of the major oil reservoirs; intermediate from the composite Cayce; and lowest from the depositionally complex and mud-rich Cornelius, which overlies the Cayce. Reservoir efficiency of the strandplain sandstones in the North Markham-North Bay City field exceeds that of barrier and back-barrier deposits productive elsewhere in the Frio Formation of the central Texas Gulf Coast.

Keywords: Texas Gulf Coast, Matagorda County, Frio Formation, North Markham-North Bay City oil field, strandplain reservoirs, reservoir architecture, oil production



CONTENTS
ABSTRACT

INTRODUCTION

Strandplain depositional systems

Beach-ridge plains

Chenier plains

Oil-bearing strandplain systems of the Texas Gulf Coast Basin

NORTH MARKHAM-NORTH BAY CITY FIELD

Oil production from the North Markham- North Bay City field

Facies influence on reservoir continuity

CAYCE RESERVOIR: A COMPOSITE PROGRADATIONAL STRANDPLAIN/FLUVIODELTAIC COMPLEX

Depositional environment

Thickness trends and sandstone distribution

Areal distribution of component facies

Interpretation of depositional environments

Architecture and dimensions of component facies

Areal stratification trends

Reservoir continuity and hydrocarbon distribution

Reservoir drainage characteristics

Water-influx trends

Reservoir productivity

CORNELIUS RESERVOIR: A PROGRADED MUD-RICH STRANDPLAIN COMPLEX

Depositional environment

Sandstone distribution

Areal distribution of component facies

Interpretation of depositional environments

Reservoir continuity and hydrocarbon distribution

Reservoir drainage characteristics

Water-influx trends

Reservoir productivity

CARLSON RESERVOIR: A TRANSGRESSED BEACH-RIDGE PLAIN

Depositional environment

Sandstone distribution

Areal distribution of component facies

Interpretation of depositional environments

Reservoir continuity

Reservoir drainage trends

CONCLUSIONS

Reservoir models

Oil recovery and fluid injection

ACKNOWLEDGMENTS

REFERENCES

Figures

1. Schematic models illustrating the principal environments of deposition in (A) beach-ridge plain, (B) chenier plain, and (C} barrier-island systems

2. Physiography of a modem beach-ridge strandplain, Nayarit coastal plain, Mexico, and a cross section illustrating the tabularity of prograding beach-ridge deposits

3. Physiography of a modem chenier plain, western Louisiana, and a cross section illustrating the shallow-based and irregular distribution of chenier plain beach ridges

4. Frio depositional systems and location of the North Markham- North Bay City field

5. Upper Frio stratigraphic dip cross section

6. Structure map of the North Markham-North Bay City field contoured on top of the Cayce sandstone

7. Generalized west-east section across the North Markham- North Bay City field

8. Percent-sandstone map, Cayce reservoir

9. Log-character and net-sandstone map, Cayce reservoir

10. Facies anatomy of the Cayce sandstone, adapted from vertical SP profiles

11. Exploded reservoir facies of the Cayce sandstone

12. Stratigraphic complexity (number of strata} map of the Cayce sandstone

13. Resistivity cross sections, east Cayce reservoir

14. Resistivity cross section, west Cayce reservoir

15. Sequential water-cut maps, east and west Cayce reservoirs

16. Reservoir productivity maps of the Cayce reservoir for periods 1942 through 1965 and 1966 through 1982

17. Net-sandstone map, Cornelius sandstone

18. Detailed net-sandstone map of the third Cornelius sandstone

19. Interpretive facies anatomy of the third Cornelius sandstone

20. Resistivity dip sections, Cornelius sandstone

21. Resistivity section aligned obliquely to the strike of the Cornelius sandstone

22. Sequential water-cut maps of the west Cornelius reservoir

23. Reservoir production maps, west Cornelius reservoir

24. Log-facies map of the Carlson sandstone

25. Resistivity cross section, Carlson reservoir

26. Water-cut and production maps of the Carlson reservoir

27. Continuity of a composite progradational beach-ridge strandplain transected by a fluvial-deltaic system modeled on the Cayce reservoir

28. Reservoir continuity models of a mud-rich beach-ridge plain complex

29. Reservoir continuity model of transgressed strandplain sandstones

Table

1. Geologic, fluid property, engineering, and production characteristics of the principal oil reservoirs of the North Markham-North Bay City field




Citation
Tyler, Noel, and Ambrose, W. A., 1985, Facies Architecture and Production Characteristics of Strandplain Reservoirs in the Frio Formation, Texas: The University of Texas at Austin, Bureau of Economic Geology, Report of Investigations No. 146, 42 p.