Oil and Gas Exploration - The Gravimetric Approach Using Subsurface G-Anomalies
Abstract
Earth’s diverse topography—including mountains, valleys, underground caverns, oceans, and glaciers—results in variations in surface mass. Since gravity is directly related to mass, slight variations in the gravitational field exist across the planet’s surface. The gravimetric method is a non-destructive geophysical technique used to measure these differences in Earth’s gravitational field at specific locations. Although the changes in gravity may be subtle, they provide critical clues to understanding the structure and composition of the solid Earth and other related phenomena. The observed surface gravity, g, results from the attraction of mass within the Earth’s interior. This work aims to highlight the practical importance of the gravimetric approach in detecting subsurface anomalies, especially in oil and gas exploration. The most commonly used data are Bouguer gravity anomalies, which reflect variations in the gravitational field caused by objects of interest, such as hydrocarbon deposits. These variations can be analyzed using various analytical and computational methods to estimate the depth, geometry, and density of the causative bodies. Therefore, this study reveals that gravimetric methods have wide applications in geophysics, engineering, environmental science, and geosciences.
Downloads
Literaturhinweise
Abdelrahman, E. M., Riad, S., Refai, E., & Amin, Y. (1985). On the least squares residual anomaly determination. Journal of Geophysics, 50(20), 473–480.
Ayeni, O. O. (2001). Statistical Adjustment and Analysis of Data. Lecture note series, Department of Surveying and Geoinformatics, University of Lagos.
Ezeigbo, C. U. (1988). A least squares collocation method of geoid and datum determination for Nigeria (Ph.D. thesis). Department of Surveying, University of Lagos.
Ezeigbo, C. U. (2010). Role of Global Earth Observation System of Systems (GEOSS) in Monitoring the Environment in Nigeria. Nigerian Union of Planetary and Radio Sciences (NUPRS).
Fajemirokun, F. A., & Orupabo, S. (1987). Residual anomalies computations. Paper presented at the International Workshop on the Stability of the Western Sector of African Plate, University of Ibadan.
Garcia-Abdeslem, J. (1996). A FORTRAN program to compute the gravity anomaly of a 2-D prism where density varies as a function of depth. Journal of Computation and Geosciences, 22, 823–826.
Gumert, W. R. (1992). Airborne gravity measurements. In Geophysical Exploration at Sea (2nd ed.). CRC Press.
Heiskanen, W. A., & Moritz, H. (1967). Physical Geodesy. W. H. Freeman and Company.
Idowu, T. O. (2005). Determination and utilization of optimum residual gravity anomalies for mineral exploration (Ph.D. thesis). Department of Surveying and Geoinformatics, University of Lagos.
Keller, R. G. (2002). Getting started with gravity and magnetic techniques: A tutorial for using and understanding gravity data. Department of Geological Sciences, Pan American Centre for Earth and Environmental Studies, University of Texas at El Paso.
Krarup, T. (1970). The method of least squares collocation. Studia Geophysica.
Moritz, H. (1972). Advanced least squares method (Report No. 175). Department of Geodetic Science, The Ohio State University.
Moritz, H. (1978). Least squares collocation. Journal of the American Geophysical Union, 16(3), 421–430.
Opeloye, S. A., & Dio, C. J. (1999). Geology and Mineral Resources of Adamawa State. 1st ed., Paraclate Publisher.
Orupabo, S., & Ajayi, G. (2010). Gravity inversion for identification of crustal anomalies and crustal dynamics: Applications in oil and gas exploration. Nigerian Union of Planetary and Radio Sciences (NUPRS).
Pwavidon, A. S. (2006). A GIS approach to water utility distribution in Karewa, Yola North Local Government Area, Adamawa State. PGD Project, Department of Surveying and Geoinformatics, Federal University of Technology, Yola.
Rapp, R. H. (1986). Global geopotential solutions. Lecture notes in Earth Sciences, Department of Geodetic Sciences and Surveying, The Ohio State University, 7, 75–181.
Richard, S. K. (1995). Exploration, drilling, and production of oil and natural gas. In Encyclopaedia of Occupational Health and Safety (4th ed.). Geneva: ILO Office.
Robinson, E. S., & Coruh, C. (1988). Basic Exploration Geophysics. John Wiley & Sons.
Roos, L. L., Roos, N. P., Cageorge, S. M., & Nicol, J. P. (1982). How good are the data? The reliability of databanks. Journal of Medical Care, 20, 266–276.
Roos, L. L., Nicol, J. P., & Wajda, A. (1989). Assessing data quality: A computerized approach. Social Science & Medicine, 28, 175–182.
Senti, R. J. (1988). Geophysical activity in 1987. Journal of Geophysics: The Leading Edge of Exploration, 7(8), 33–56.
SNEPCO. (1995). Final report of Gongola Basin, Nigeria.
Sonukan, W. (1998). Gravity and internal structures: An investigation (M.Sc. Project Report). University of Lagos.
Telford, W. M., Geldart, L. P., Sheriff, R. E., & Keys, D. A. (1990). Applied Geophysics (2nd ed.). Cambridge University Press.
Theophile Ndougsa-Mbarga, Eliezer Manguelle-Dicoum, Jose-Oscar Campos-Enriquez, & Yene Atangana. (2007). Gravity anomalies, subsurface structure and oil and gas migration in the Mamfe, Cameroon-Nigeria sedimentary basin. Geofisica International, 46, 129–139.
