1887
2nd Australasian Exploration Geoscience Conference: Data to Discovery
  • ISSN: 2202-0586
  • E-ISSN:
PDF

Abstract

Summary

In situ overpressures in sedimentary basins are commonly attributed to disequilibrium compaction or fluid expansion mechanisms, though overpressures in shallow sedimentary sequences may also develop by vertical transfer of pressure from deeper basin levels, for example via faults. Mafic sill complexes are common features of sedimentary basins at rifted continental margins, often comprising networks of interconnected sills and dikes that facilitate the transfer of magma over considerable vertical distances to shallow basinal depths. Here we document evidence for deep sills (depths >5 km (16,000 ft)) hosting permeable, open fracture systems that may have allowed transmission of overpressure from ultra-deep basinal (>7 km (23,000 ft)) levels. Most notably, well 214/28-1 encountered overpressured, thin (<8 m (26 ft)) and fractured gas-charged intrusions, which resulted in temporary loss of well control. While the overpressure could reflect local gas generation related to thermal maturation of Cretaceous shales into which the sills were emplaced, this would require the overpressures to have been sustained for unfeasibly long timescales (>58 Myr). We instead suggest that transgressive, interconnected sill complexes, such as those penetrated by well 214/28-1, may represent a previously unrecognized mechanism of transferring overpressures (and indeed hydrocarbons) laterally and vertically from deep to shallow levels in sedimentary basins, and that they represent a potentially under-recognized hazard to both scientific and petroleum drilling in the vicinity of subsurface igneous complexes.

© 2019 Taylor and Francis Group LLC
Loading

Article metrics loading...

/content/journals/10.1080/22020586.2019.12073096
2019-12-01
2026-01-22

  • From This Site

    /content/journals/10.1080/22020586.2019.12073096
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Board, M., 2012, Macondo Well Deepwater Horizon Blowout: Lessons for Improving Offshore Drilling Safety. National Academies Press.
  2. Cartwright, J. and Møller Hansen, D., 2006. Magma transport through the crust via interconnected sill complexes. Geology, 34(11), pp.929-932.
  3. Cartwright, J., Huuse, M. and Aplin, A., 2007. Seal bypass systems. AAPG bulletin, 91(8), pp.1141-1166.
  4. Constable, M. V., Antonsen, F., Stalheim, S. O., Olsen, P. A., Fjell, O. Z., Dray, N. Tan, S. (2016, October 1). Looking Ahead of the Bit While Drilling: From Vision to Reality. Society of Petrophysicists and Well-Log Analysts.
  5. Edwards, A., O’Connor, S., Swarbrick, R., Alderson, A. and Diaz, M. 2012. Overpressure mapping in the West of Shetlands Basin. Abstract, PETEX, London.
  6. Fan, C., Wang, Z., Wang, A., Fu, S., Wang, L., Zhang, Y., Kong, H. and Zhang, X., 2016. Identification and calculation of transfer overpressure in the northern Qaidam Basin, northwest China. AAPG Bulletin, 100(1), pp.23-39.
  7. Hoskins, E., O’Connor, S., Robertson, S., Streit, J., Ward, C., Lee, J. and Flett, D. Influence of faulting on reservoir overpressure distribution in the Northern Carnarvon Basin. APPEA Journal, 1-13.
  8. Illife, J.E., Robertson, A.G., Ward, G.H.F., Wynn, C., Pead, S.D.M., and Cameron, N. 1999. The importance of fluid pressures and migration to the hydrocarbon propectivity of the Fareo-Shetland White Xone, in Fleet, A.J. and Boldy, S.A.R. eds., Petroleum Geology of Northwest Europe: Proceedings of the 5th Conference, London, The geological Society, London, 601-611.
  9. Luo, X. and Vasseur, G. 2016. Overpressure dissipation mechanisms in sedimentary sections consisting of alternating mud-sand layers. Marine and Petroleum Geoscience, 78 883-894. Mann, D.M. and Mackenzie, A.S., 1990. Prediction of pore fluid pressures in sedimentary basins. Marine and Petroleum Geology, 7(1), pp.55-65.
  10. Mark, NJ., Schofield, N., Pugliese, S., Watson, D., Holford, S., Muirhead, D., Brown, R. and Healy, D. (2017) 'Igneous intrusions in the Faroe Shetland basin and their implications for hydrocarbon exploration: new insights from well and seismic data'. Marine and Petroleum Geology. doi: 10.1016/J.MARPETGEO.2017.12.005
  11. Osborne, M.J. and Swarbrick, R.E., 1997. Mechanisms for generating overpressure in sedimentary basins: A reevaluation. AAPG bulletin, 81(6), pp.1023-1041.
  12. Schofield, N.J., Brown, D.J., Magee, C. and Stevenson, C.T., 2012. Sill morphology and comparison of brittle and non-brittle emplacement mechanisms. Journal of the Geological Society, 169(2), pp.127-141.
  13. Schofield, N., Holford, S., Millet, J., Brown, D., Jolley, D., Passey, S.R., Muirhead, D., Grove, C., Magee, C., Murray, J., Hole, M., Jackson, C.A.-L., Stevenson, C., 2015. Regional magma plumbing and emplacement mechanisms of the Faroe-Shetland Sill Complex: implications for magma transport and petroleum systems within sedimentary basins. Basin Res. 19. http://doi.org/10.1111/bre.12164.
  14. Swarbrick, R.E., Osborne, M.J. and Yardley, G.S., 2001, AAPG Memoir 76, Chapter 1: Comparision of Overpressure Magnitude Resulting from the Main Generating Mechanisms.
  15. Tassone, D.R., Holford, S.P., Stoker, M.S., Greem P., Johnson, H., Underhill, J.R. and Hillis, R.R. 2014. Constraining Cenozoic exhumation in the Faroe-Shetland region using sonic transit time data. Basin Research, 26, 38-72.
  16. Tingate, P.R., Khaksar, A., van Ruth, P., Dewhurst, D.N., Raven, M.D., Young, H., Hillis, R. R., and Dodds, K. 2001. Geological controls on overpressure in the Northern Carnarvon Basin. APPEA Journal 573-593.
  17. Tingay, M.R., Hillis, R.R., Swarbrick, R.E., Morley, C.K. and Damit, A.R., 2007, ‘Vertically transferred’overpressures in Brunei: Evidence for a new mechanism for the formation of high-magnitude overpressure. Geology, 35(11), pp.1023-1026
  18. Tingay, 2015, Initial pore pressures under the Lusi mud volcano, Indonesia. Interpretation, 3, 33-49.
  19. Traugott, Martin O., and Phillip D. Heppard. "Prediction of pore pressure before and after drilling—Taking the risk out of drilling overpressured prospects." AAPG Hedberg Research Conference. Vol. 70. 1994.
  20. Van Ruth, P.J., Hillis, R.R., Swarbrick, R. and Tingate, P. 2000. Mud weights, transient pressure tests and the distribution of overpressue in the North West Shelf, Australia, Petroleum Exploration Society Australia Journal 28, 59-66.
/content/journals/10.1080/22020586.2019.12073096
Loading
  • Article Type: Research Article
Keyword(s): drilling; exploration; intrusions; overpressure; sills

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error