Prasanta K Patro
The generation and accumulation of hydrocarbons (oil and gas) are associated with some specific geological environment and settings. Different geophysical methods try to delineate these specific geological settings as the direct detection of HC is a difficult task. Though seismic is mostly preferred method to detect the HC bearing structures, still, it has limitations in the regions covered by basalts or carbonate rocks. In such cases, electromagnetic (EM) exploration techniques, especially magnetotelluric (MT), play an important and, in some cases, a crucial role in mapping these potential reservoirs because of significant resistivity contrast observed between the basalts and the underlying sedimentary layers. In the case of geothermal exploration, EM techniques, particularly MT, are known to be highly useful in deciphering the target areas because of the conductivity structures arising from the presence and circulation of highly conductive fluids (because of dissolved salts) in the geothermal target areas. The temperature of the system further modulates the electrical conductivity of the assembly. Thus, the geothermal system including fluids and rock matrix, in general, presents itself as an electrically anomalous conductive target and the EM methods, MT in particular, become the favorite tool to detect and image such significantly anomalous conductive zones over a range of depths in a given region of geothermal significance.
This review paper presents the current scenario of application of MT and other EM methods in the exploration of hydrocarbons and geothermal resources in Asia. A few case histories are presented that typically illustrate the role and effectiveness of MT and other EM techniques such as CSEM, TEM, TFEM, etc. in this context. A few examples of MT studies carried out in some of the potential areas of hydrocarbon, and geothermal significance in the Asian region are also discussed.
Patro, P. K., Magnetotelluric studies for hydrocarbon and geothermal resources: Examples from the Asian region, Surveys in Geophysics, DOI 10.1007/s10712-017-9439-x
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