Sedimentary Record of Cretaceous and Tertiary Salt Movement, East Texas Basin: Times, Rates, and Volumes of Salt Flow

RI0139. Sedimentary Record of Cretaceous and Tertiary Salt Movement, East Texas Basin: Times, Rates, and Volumes of Salt Flow and Their Implications for Nuclear Waste Isolation and Petroleum Exploration, by S. J. Seni and M. P. A. Jackson, assisted by R. E. Bramson, R. J. Burks, R. D. Conti, S. A. Ghazi, S. E. Lovell, B. C. Richter, J. L. Smith, and D. H. Wood. 89 p., 57 figs., 7 tables, 1984. ISSN: 0082335X: Print.



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Excerpted from the ABSTRACT
Post-Aptian strata (younger than 112 ma) in the East Texas Basin were strongly influenced by halokinesis and recorded the evolution associated sate structures. Comparisons with model diapirs and dome-induced changes in patterns of sandstone distribution, depositional facies, and reef growth indicate that thickness variations in strata surrounding domes were caused by syndepositional processes rather than by tectonic distortion.
           Salt domes in the East Texas Basin exhibit three stages of growth: pillow, diaper, and postdiapir. Each stage affected surrounding strata differently. Pillow growth caused broad uplifting of strata over the crest of the pillows. The resulting topographic swells influenced depositional trends and were susceptible to erosion. Fluvial-channel systems bypassed pillow crests and stacked vertically in primary peripheral sinks on the updip flanks of the pillows. Diapir growth was characterized by expanded sections of shelf and deltaic strata in secondary peripheral sinks around the diapirs. Lower Cretaceous (Aptian stage) reefs on topographic saddles between secondary peripheral sinks now host major oil production at Fairway Field. Postdiapir crestal uplifting and peripheral subsidence affected smaller areas than did equivalent processes that occurred during pillow or diaper stages…
          Long-term and recent rates of dome growth in East Texas indicate a low probability that future dome uplift will breach an intradomal waste repository. During deposition of the Eocene Wilcox Group, fine-grained floodplain sediments accumulated over and around active diapirs in the East Texas Basin, including Oakwood salt dome. These fine-grained sediments now sheathing diapirs are aquitards favorable for waste isolation. However, sand-rich channel facies in rim synclines commonly surround the fine-grained sheath and constitute interconnected aquifers around diapirs. A potential pathway for radionuclides leaking from a dome could occur if interconnected aquifers intercept the dome. Dome-specific facies variability is difficult to detect because the variability commonly exceeds available well spacing. Site characterization of a potential waste repository must therefore be based on dense well control and on an understanding of dome growth history and diapiric processes in order to better predict facies distributions around domes.
         Facies variations over and around domes at different stages of growth enable prediction of the location of subtle, facies-controlled hydrocarbon traps. These facies traps are likely to be the only undiscovered traps remaining in mature petroliferous basins such as the East Texas Basin.



Keywords: Cretaceous-Tertiary, depositional facies, East Texas Basin, petroleum exploration, petroleum traps, rates of dome growth, salt domes, salt tectonics, stress-strain, waste disposal



CONTENTS
ABSTRACT

INTRODUCTION

Data base

Early history of basin formation and filling

Geometry of salt structures

EVOLUTIONARY STAGES OF DOME GROWTH

Pillow stage

Geometry of overlying strata

Geometry of surrounding strata

Depositional facies and lithostratigraphy

Diapir stage

Geometry of surrounding strata

Depositional facies and lithostratigraphy

Postdiapir stage

Geometry of surrounding strata

Depositional facies and lithostratigraphy

Holocene analogs

Summary

Formation of subtle petroleum traps

PATTERNS OF SALT MOVEMENT IN TIME AND SPACE

Group 1 diapirs: Pre-Glen Rose Subgroup (pre-112 Ma)

Group 2 diapirs: Glen Rose Subgroup to Washita Group (112 to 98 Ma)

Group 3 diapirs: Post-Austin Group (86 to 56 Ma)

Initiation and acceleration of salt flow

Overview of dome history

RATES OF SALT MOVEMENT AND DOME GROWTH

Propositions

Proven propositions

Unproven propositions

Simplified propositions

Distinguishing between syndepositional and postdepositional thickness variations

The problem

Structural evidence

Sedimentological evidence

Methodology

Distinguishing between regional and salt-related thickness variations

Calculating volumes of salt mobilized and of salt lost

Rates of dome growth

Net rates of pillow growth

Net rates of diapir growth

Gross rates of diapir growth

Growth rates and strain rates

IMPLICATIONS FOR WASTE ISOLATION

CONCLUSIONS

ACKNOWLEDGMENTS

REFERENCES

APPENDICES

1. Calculation of diapiric strain rates from diapiric growth rates

2. List of wells by cross sections

Figures

1. Location map showing the East Texas Basin and surrounding area

2. Index map of the East Texas Basin showing cross-section lines and logged wells

3. Stratigraphic column of the East Texas Basin

4. Schematic cross sections showing evolution of the East Texas Basin and the Gulf of Mexico

5. Schematic block diagrams of facies around salt structures during early evolution of the East Texas Basin

6. Isometric block diagrams of salt structures in the East Texas Basin

7. Structure map showing four salt provinces in the East Texas Basin

8. Schematic stages of dome growth and characteristics of strata, East Texas Basin

9. Mapped areas of stratal thinning over salt pillows in the East Texas Basin

10. Southwest-northeast cross section and map, Hainesville Dome

11. Map of primary peripheral sinks, East Texas Basin

12. Map of net sandstone, Paluxy Formation

13. Cross section D-D', Paluxy Formation, across Van, Hainesville, and Hawkins salt structures

14. Schematic cross sections showing inferred evolution of salt structures.

15. Map of secondary peripheral sinks, East Texas Basin

16. Cross section U-U', Hainesville Dome area

17. lsopach map, Lower Taylor Formation - Austin Group, Hainesville Dome area

18. lsopach map of salt-withdrawal basins, Paluxy and Walnut Formations

19. lsopach map of salt-withdrawal basins, Washita Group

20. lsopach map of salt-withdrawal basins, Glen Rose Subgroup

21. Cross section Z-Z', Glen Rose Subgroup.

22. Cross section X-X', and maps of isopach, net sandstone, and structure, Paluxy Formation

23. Map of tertiary peripheral sinks, Wilcox Group, southern part of the East Texas Basin

24. Sand-percent map, Wilcox Group

25. Cross section B-B', Wilcox Group, Bethel Dome area

26. Cross section A-A', Wilcox Group, Oakwood Dome area

27. Relation between above-dome topography and surficial sand distribution, Upper Texas Gulf Coast

28. Location map of Hormuz salt plugs and Yas Island salt dome, Persian Gulf

29. Schematic block diagrams of facies around salt structures during late evolution of the East Texas Basin

30. Schematic cross section through a mature diapir showing typical facies variations and potential petroleum traps

31. Three groupings of domes in the East Texas Basin based on the timing of stages of salt movement

32. Map of three age groups of salt diapirs in the East Texas Basin

33. Regional isopach map, Glen Rose Subgroup

34. Regional isopach map, Paluxy and Walnut Formations

35. Regional isopach map, Lower Taylor Formation and Austin Group

36. Technique for calculating the volume of a salt-withdrawal basin

37. Dome-growth-rate curves calculated on the basis of compacted and decompacted sediments, East Texas Basin

38. Percentage thickness change around selected diapirs and pillows in the East Texas Basin

39. Fold-shape analysis

40. Cross sections of model domes

41. Measurement of isochore thickness parameters in model domes

42. Histograms showing frequency distribution of thickness changes in model domes

43. Comparison of axial-trace positions for salt domes in the East Texas Basin and for model domes

44. Cross sections of Hainesville, Grand Saline, and Keechi Domes

45. Methods of calculating net and gross rates of dome growth

46. Histograms of thickness and rate of regional sediment accumulation of major stratigraphic units in the East Texas Basin

47. Cumulative-probability curves of sediment-accumulation rate in the East Texas Basin

48. Contour map showing sample grid spacing and standard deviation of sediment-accumulation rate, Lower Taylor Formation and Austin Group

49. Histogram of the volumes of salt-withdrawal basins and volumetric rates at which salt-withdrawal basins were filled in the East Texas Basin

50. Histogram of the volumes of salt-withdrawal basins for diapirs in the East Texas Basin

51. Net rates of salt-pillow growth, East Texas Basin

52. Maximum net rates of dome growth, Oakwood and Hainesville Domes

53. Maximum net rates of dome growth and mean rate of regional sediment accumulation in the East Texas Basin

54. Residual rates of dome growth for 16 East Texas salt domes

55. Gross rates of dome growth in the East Texas Basin

56. Hypothetical gross and actual heights of diapirs in the East Texas Basin

57. Comparison of published net and gross rates and methods of dome growth

Tables

1. Net rate of pillow growth, East Texas Basin

2. Net rate of diapir growth, East Texas Basin

3. Gross rate of diapir growth, East Texas Basin

4. Statistical analysis of data on thickness and rate of regional sediment accumulation for major stratigraphic units, East Texas Basin

5. Volume of salt-withdrawal basins, East Texas Basin

6. Comparison of rates of salt-dome growth and methods used to calculate them

7. Overall and fastest bulk-strain rates in East Texas Basin salt diapir



Citation
Seni, S. J., and Jackson, M.P.A., 1984, Sedimentary Record of Cretaceous and Tertiary Salt Movement, East Texas Basin: Times, Rates, and Volumes of Salt Flow and Their Implications for Nuclear Waste Isolation and Petroleum Exploration: The University of Texas at Austin, Bureau of Economic Geology, Report of Investigations No. 139, 89 p.