Formation of the Wink Sink, A Salt Dissolution and Collapse Feature, Winkler County, Texas

RI0114. Formation of the Wink Sink, A Salt Dissolution and Collapse Feature, Winkler County, Texas, by R. W. Baumgardner, Jr. A. D. Hoadley, and A. G. Goldstein. 38 p., 22 figs., 5 tables, 1982. ISSN: 0082335X: Print.

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ABSTRACT
The Wink Sink in Winkler County, Texas, formed on June 3, 1980. Within 24 hours it had expanded to a maximum width of 360 ft (110 m). On June 5, 1980, maximum depth of the sinkhole was 110 ft (34 m), and volume about 5.6 million ft³ (158,600 m³). Between June 3 and June 6, 1980, a large area bordering the south rim of the sink subsided about 10 ft (3 m) relative to the north side. Further subsidence of 1,456 ft (44.4 cm) occurred along the southern rim between July 19 and December 12, 1980.

A probable precursor of the sinkhole was a solution cavity that migrated upward by successive roof failures, thereby producing a collapse chimney filled with brecciated rock. Dissolution of salt in the Permian Salado Formation is inferred to have produced the solution cavity. Depth of the Salado ranges from 1,300 to 2,200 ft (396 to 670 m). Data on the size and initial depth of the solution cavity are unavailable.

The Salado Formation in the region contains several dissolution zones. Occurrence of dissolution in the middle of the Salado evaporite sequence may have resulted from groundwater flow along fractured anhydrite interbeds. Water may have come in contact with salt by downward movement from overlying aquifers or by upward movement from underlying aquifers under artesian pressure.

The Wink Sink lies directly above the Permian Capitan Reef, which contains water that is unsaturated with respect to sodium chloride. Hydraulic head of water from the reef is higher than the elevation of the Salado Formation but lower than the head in the Triassic Santa Rosa Formation, a near-surface fresh-water aquifer. Fracture or cavernous permeability occurs above, within, and below the Salado Formation, as indicated by the loss of circulation of drilling fluid in wells drilled near the sinkhole. Consequently, a brine density-flow cycle may be operating: relatively fresh water moves upward under artesian pressure and dissolves salt; the denser brine moves downward under gravity flow in the same fracture system. Alternatively, downward flow of water from aquifers such as the Santa Rosa Formation or Quaternary sediments above the salt is also a possible explanation for dissolution. A plugged and abandoned well that was located within the circumference of the sinkhole may have provided a conduit for water movement.

Composition of water in the Wink Sink resembles that of water in nearby wells producing from the Quaternary alluvium and from the Triassic Santa Rosa Formation.

Hendrick well number 10-A was drilled in 1928 at a site now within the circumference of the sinkhole. The well, which initially produced about 80 percent water from the Permian Tansill Formation, was plugged with cement and abandoned in 1964. The well was not used for brine disposal. Over 12 million barrels of salt water produced from the Hendrick Field were disposed of by injection into the Permian Rustler Formation during 1961. Waterflood projects in the Hendrick Field began in 1963 and are still in progress.

Sinkholes similar to the Wink Sink occur in other areas of North America. Their morphology, associated strata, and mode of formation suggest that dissolution, brecciation, and surface subsidence commonly occur during their formation.

Keywords: salt (halite) dissolution, Permian Salado Formation, Capitan Reef, sinkhole, Triassic, Santa Rosa Formation, collapse sinkhole, abandoned oil well, West Texas, Winkler County, Wink Sink, Texas

CONTENTS

ABSTRACT

INTRODUCTION

REGIONAL GEOLOGIC SETTING

Surficial geology

Stratigraphy

Structural geology

SALT DISSOLUTION IN THE DELAWARE BASIN

History of salt dissolution

Mechanisms of salt dissolution

Brine-density flow

Downward ground-water flow

Dissolution phenomena in the Delaware Basin

Collapse features

Pecos River salt load

DEVELOPMENT OF THE WINK SINK

Mechanisms of dissolution

Local geologic setting

Stratigraphy and structural geology

Gravity survey

First-order leveling survey

Hydrology of the Wink

Water-level changes

Water chemistry

HISTORY OF HENDRICK WELL NUMBER 10-A

BRINE PRODUCTION AND INJECTION

SUBSIDENCE FEATURES IN WESTERN WINKLER COUNTY

SINKHOLES IN OTHER AREAS

CONCLUSIONS

ACKNOWLEDGMENTS

REFERENCES

APPENDIX A. DESCRIPTION OF STRATIGRAPHIC UNITS

APPENDIX B. WELLS CITED IN THE TEXT

APPENDIX C. CHANGES IN SURFACE ELEVATION AT WINK SINK

Figures

1. Aerial and ground-level oblique photographs of the Wink Sink

2. Local setting of the Wink Sink

3. Tension fractures near the Wink Sink

4. Generalized geologic map of southern Winkler County, Texas

5. Structural setting of West Texas and eastern New Mexico

6. Regional east-west cross section A-A'

7. Local east-west cross section B-B'

8. Structure-contour map on base of Tansill Formation

9. Structure-contour map on top of Rustler Formation

10. lsopach map of Salado and Tansill Formations

11. Aquifer systems and salt dissolution

12. Schematic diagram of static fluid levels for formations in southwest Winkler County

13. Dissolution and collapse features in the Delaware

14. Evidence of salt dissolution and collapse near Wink Sink

15. Detailed east-west cross section C-C' at Wink Sink

16. Local north-south cross section D-D' at Wink Sink

17. Complete Bouguer anomaly values for gravity stations near Wink Sink

18. Bouguer anomaly values for West Texas and eastern New Mexico

19. Changes of surface elevation at Wink Sink taken from results of first-order leveling surveys

20. Total dissolved solids for water samples from wells in southern Winkler County

21. Hendrick well number 10-A

22. Water used in waterflood projects, Winkler County, Texas

Tables

1. Stratigraphic section examined in this report

2. Thickness of Salado Formation

3. Formation pressure data from drill-stem tests

4. Chemical analyses of water samples from Wink Sink and nearby wells

5. Driller's log for Hendrick well number 10-A



Citation
Baumgardner, R. W., Hoadley, A. D., and Goldstein, A. G., 1982, Formation of the Wink Sink, A Salt Dissolution and Collapse Feature, Winkler County, Texas: The University of Texas at Austin, Bureau of Economic Geology, Report of Investigations No. 114, 38 p.