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4 - Gravity and Magnetics

Published online by Cambridge University Press:  25 November 2021

Hamish Wilson
Affiliation:
BluEnergy Ltd
Keith Nunn
Affiliation:
Nunngeo Consulting Ltd
Matt Luheshi
Affiliation:
Leptis E&P Ltd
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Summary

The gravity and magnetic survey methods have been in use since the early days of geophysical prospecting for petroleum. They find most application in frontier exploration. In that context, regional and global datasets are often available to assist with early evaluations.

The design and execution of modern, targeted surveys has been transformed as a result of advances in instruments and the advent of satellite navigation. Imaging and interpretive techniques have been transformed by modern computer-based approaches. The potential field methods are extremely cost-effective at delineation of basins and determining structural controls on those basins, especially delineating normal faulting within rift basins. Magnetic surveys yield depth to basement and delineate any igneous rocks present. Such surveys therefore enable early decisions about cost-effective placement of seismic surveys and other intensive follow-ups.

In more mature exploration, gravity and gravity gradient data combine well with seismic data in distinguishing between alternate interpretations, thereby removing ambiguities. High-resolution magnetic data offer an effective means of fault connection in conjunction with regional seismic coverage, if shales or mudstones are present.

In a production environment, gravity logging is the most sensitive density log available, and 4D-gravity finds application in gas production and also water-flood monitoring.

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Publisher: Cambridge University Press
Print publication year: 2021

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References

Bonvalot, S., Balmino, G., Briais, A., et al., 2012. World Gravity Map. Commission for the Geological Map of the World. Paris: BGI-CGMW-CNES-IRD.Google Scholar
Brahimi, S., Le Maire, P., Ghienne, J. F. and Munschy, M., 2020. Deciphering channel networks from aeromagnetic potential field data: The case of the North Sea Quaternary tunnel valleys. Geophysical Journal International, 220, 1447–62. DOI: 10.1093/gji/ggz494.Google Scholar
Braitenberg, C., 2014. Exploration for tectonic structures with GOCE in Africa and across-continents. International Journal of Applied Earth Observation and Geoinformation, 35(Pt A), 8895. DOI: 10.1016/j.jag.2014.01.013.Google Scholar
Burney, C., FitzGerald, D. and Zengerer, M., 2014. Non-seismic geophysical modelling methods for realistic characterisation of 3D geology in greenfields exploration. Poster paper presented at the 38th Indonesian Petroleum Association (IPA) Annual Convention and Exhibition, Jakarta, 21–23 May 2014.Google Scholar
Chandler, V. W. and Lively, R. S., 2015. 2011 Rock properties database: Density, magnetic susceptibility, and natural remanent magnetization of rocks in Minnesota. Retrieved from the Data Repository for the University of Minnesota, DOI: 10.13020/D63S3D.CrossRefGoogle Scholar
Chapin, D., 1998. The isostatic gravity residual of onshore South America: Examples of the utility of isostatic gravity residuals as a regional exploration tool. In Geologic Applications of Gravity and Magnetics: Case Histories, 34–6. SEG Reference Series No 8. AAPG Studies in Geology No. 43. Tulsa, OK: Society of Exploration Geophysicists & American Association of Petroleum Geologists.Google Scholar
Cowan, D. R. and Cowan, S., 1993. Separation filtering applied to aeromagnetic data. Exploration Geophysics, 24(4), 429–36. DOI: 10.1071/EG993429.Google Scholar
Coyle, M., Dumont, R., Keating, P., Kiss, F. and Miles, W., 2014. Geological Survey of Canada aeromagnetic surveys: Design, quality assurance and data dissemination. Geological Survey of Canada Open File 7660.Google Scholar
Gardner, G. H. F., Gardner, L. W. and Gregory, A. R., 1974. Formation velocity and density: The diagnostic basics for stratigraphic traps. Geophysics, 39(6), 770–80. DOI: 10.1190/1.1440465.Google Scholar
GEBCO. 2020. General Bathymetric Chart of the Oceans. GEBCO Compilation Group (2020) GEBCO 2020 Grid. DOI: 10.5285/a29c5465-b138-234d-e053-6c86abc040b9.Google Scholar
Gibson, R. I. and Millegan, P. S. (eds.), 1998. Geologic Applications of Gravity and Magnetics: Case Histories. SEG Reference Series No. 8. AAPG Studies in Geology No 43. Tulsa, OK: Society of Exploration Geophysicists & American Association of Petroleum Geologists.CrossRefGoogle Scholar
Hammer, S., 1983. Airborne gravity is here! Geophysics, 48(2), 213–23. DOI: 10.1190/1.1441460.Google Scholar
Hare, J. L., Ferguson, J. F. and Brady, J. L., 2008. The 4D microgravity method for waterflood surveillance. Part IV: Modelling and interpretation of early epoch 4D gravity surveys at Prudhoe Bay, Alaska. Geophysics, 73(6), WA173WA180. DOI: 10.1190/1.2991120.Google Scholar
Hartman, R. R., Friedberg, J. L. and Teskey, D. J., 1971. A system for rapid digital aeromagnetic interpretation. Geophysics, 36(5), 891918. DOI: 10.1190/1.1440223.Google Scholar
Lasky, R. P., Mory, A. J., Ghori, K. A. R. and Shevchenko, S. I.., 1998. Structure and petroleum potential of the southern Merlinleigh sub-basin, Carnarvon Basin, Western Australia, Report 61, Geological Survey of Western Australia.Google Scholar
Lovley, D. R., Stolz, J. F., Nord, G. L. Jr. and Phillips, E. J. P., 1987. Anaerobic production of magnetite by a dissimilatory iron-reducing microorganism. Nature, 330(6144), 252–4. DOI: 10.1038/330252a0.Google Scholar
Milton-Worssell, R., Smith, K., McGrandle, A., Watson, J. and Cameron, D., 2010. The search for a Carboniferous petroleum system beneath the Central North Sea. In Vining, B. A. and Pickering, S. C. (eds.), Petroleum Geology: From Mature Basins to New Frontiers: Proceedings of the 7th Petroleum Geology Conference, 5775, London: Geological Society. DOI: 10.1144/0070057.Google Scholar
Minty, B. R. S., 2011. Airborne geophysical mapping of the Australian continent. Geophysics, 76(5), A27A30. DOI: 10.1190/geo2011–0056.1.Google Scholar
Moorkamp, M., Roberts, A. M., Jegen, M., Heincke, B. and Hobbs, R. W., 2013. Verification of velocity-resistivity relationships derived from structural joint inversion with borehole data. Geophysical Research Letters, 40(14), 3596–601. DOI: 10.1002/grl.50696.Google Scholar
Morgan, R., 1998. Magnetic anomalies associated with the North and South Morecambe Field, U.K. In Geologic Applications of Gravity and Magnetics: Case Histories, 85–91. SEG Reference Series No 8. AAPG Studies in Geology No. 43. Tulsa, OK: Society of Exploration Geophysicists & American Association of Petroleum Geologists.Google Scholar
Mushayandebvu, M. F., van Driel, P., Reid, A. B. and Fairhead, J. D., 2001. Magnetic source parameters of two-dimensional structures using extended Euler deconvolution. Geophysics, 66(3), 814–23. DOI: 10.1190/1.1444971.Google Scholar
Nabighian, M. N., Grauch, V. J. S., Hansen, R. O., et al., 2005a. The historical development of the magnetic method in exploration. Geophysics, 70(6), 33ND61ND. DOI: 10.1190/1.2133784.Google Scholar
Nabighian, M. N., Ander, M. E., Grauch, V. J. S., et al., 2005b. The historical development of the gravity method in exploration. Geophysics, 70(6), 33ND89ND. DOI: 10.1190/1.2133785.Google Scholar
Naudy, H., 1971. Automatic determination of depth on aeromagnetic profiles. Geophysics, 36(4), 717–22. DOI: 10.1190/1.1440207.CrossRefGoogle Scholar
Pawlowski, R., 2020. Years of Arabian Peninsula gravity exploration by Chevron and its legacy companies, including discovery of the Ghawar and Burgan super-giants. The Leading Edge, 39(4), 279–83. DOI: 10.1190/tle39040279.1.CrossRefGoogle Scholar
Reid, A. B., 1980. Aeromagnetic survey design. Geophysics, 45(5), 973–6. DOI: 10.1190/1.1441102.Google Scholar
Reid, A. B., 1994. High resolution aeromagnetic data: New tricks for an old dog! Poster paper at GEO’94, Middle East Geoscience Conference, Bahrain, 1994.Google Scholar
Reid, A. B., Allsop, J. M., Granser, H., Millett, A. J. and Somerton, I. W., 1990. Magnetic Interpretation in three dimensions using Euler Deconvolution. Geophysics, 55(1), 8091. DOI: 10.1190/1.1442861.Google Scholar
Reid, A. B., Ebbing, J. and Webb, S. J., 2014. Avoidable Euler errors: The use and abuse of Euler deconvolution applied to potential fields. Geophysical Prospecting, 62(5), 1162–8. DOI: 10.1111/1365-2478.12119.Google Scholar
Reynolds, R. L., Fishman, N. S., Wanty, R. B. and Goldhaber, M. B., 1990, Iron sulphide minerals at Cement oilfield, Oklahoma: Implications for magnetic detection of oilfields. Geological Society of America Bulletin, 102, 368–80. DOI: https://bit.ly/2M9X4zo.Google Scholar
Saad, A., 2018a. Sedimentary magnetic anomalies. Part 1: The validity of short-wavelength, low amplitude SEDMAG anomalies. The Leading Edge, 37(10), 774–9. DOI: 10.1190/tle37100774.1.Google Scholar
Saad, A., 2018b. Sedimentary magnetic anomalies. Part 2: Examples, sources and geologi9 origin of SEDMAG anomalies. The Leading Edge, 37(10), 830–7. DOI: 10.1190/tle37110830.1.Google Scholar
Salem, A., Williams, S., Fairhead, D., Smith, R. and Ravat, D., 2008. Interpretation of magnetic data using tilt-angle derivatives. Geophysics, 73(1), L1L10. DOI: 10.1190/1.2799992.Google Scholar
Salem, A., Williams, S., Samson, E., Fairhead, J. D., Ravat, D. and Blakely, R. J., 2010. Sedimentary basins reconnaissance using magnetic tilt-depth method. Exploration Geophysics, 41(3), 198209. DOI: 10.1071/EG10007.Google Scholar
Smith, R. S., Thurston, J. B., Dai, T. F. and MacLeod, I. N., 1998. iSPITM: The improved source parameter imaging method. Geophysical Prospecting, 46(2), 141–51. DOI: 10.1046/j.1365-2478.1998.00084.x.CrossRefGoogle Scholar
Smith, R. S., Thurston, J. B., Salem, A. and Reid, A. B., 2012. A grid implementation of the SLUTH algorithm for visualising the depth and structural index of magnetic sources. Computers & Geosciences, 44, 100–8. DOI: 10.1016/j.cageo.2012.03.004.Google Scholar
Spector, A. and Grant, F. S., 1970. Statistical models for interpreting aeromagnetic data. Geophysics, 35(2), 293302. DOI: 10.1190/1.1440092.Google Scholar
Vacquier, V., Steenland, N. C., Henderson, R. G. and Zeitz, I., 1951. Interpretation of Aeromagnetic Maps. Geological Society of America Memoir 47. Boulder, CO: Geological Society of America.Google Scholar
Verduzco, B., Fairhead, J. D. and MacKenzie, C., 2004. New insights into magnetic derivatives for structural mapping. The Leading Edge, 23(2), 116–19. DOI: 10.1190/1.1651454.Google Scholar
Vixo, D and Connard, G., 2020. Isostatic gravity inversion: A new way to model gravity data. First Break, 38(5), 4351. DOI: 10.3997/1365-2397.fb2020033.Google Scholar
Watts, A. B., 2001. Isostasy and Flexure of the Lithosphere. Cambridge: Cambridge University Press.Google Scholar
Werner, S., 1955. Interpretation of magnetic anomalies at sheet-like bodies. Sveriges Geologiska Undersökning, Årsbok, 43(1949), 6.Google Scholar

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