Magnetotelluric exploration for hydrocarbons

Journal Article · Wed Feb 01 04:00:00 EST 1989 · Proc. IEEE (Inst. Electr. Electron. Eng.); (United States)

DOI:https://doi.org/10.1109/5.18627· OSTI ID:5969564

Orange, A S

The magnetotelluric (MT) method utilizes naturally occurring low frequency electromagnetic energy to determine the electrical resistivity of the earth's subsurface. The resistivity distribution of the subsurface is then interpreted in terms of rock type and geologic structure. MT derived resistivity data are usually integrated with other geophysical results, and with surface and subsurface geologic data if available, to arrive at an interpretation. This paper reviews the basic relationships that govern the application of MT to hydrocarbon exploration; the electrical properties of rocks, MT energy sources, and briefly, MT theory. Data acquisition and processing and field procedures are covered. By measuring the complete vector electromagnetic field, an impedance tensor may be calculated which, when evaluated as a function of frequency, samples the electrical characteristics of the earth as a function of depth through the skin depth relationship. The impedance is simply related to an apparent resistivity. The use of a tensor impedance relationship is necessitated by the distortion imposed on the electromagnetic field by lateral variations in subsurface resistivity. Data analysis and modeling techniques have been developed which aid in the interpretation of the resistivity tensor in terms of complex structure. The paper includes a discussion of current usage, concluding with representative case studies, which illustrate the application of MT to hydrocarbon exploration problems.

• Research Organization: Emerald Exploration Consultants, Inc., Austin, TX (US)
• OSTI ID: 5969564
• Journal Information: Proc. IEEE (Inst. Electr. Electron. Eng.); (United States), Journal Name: Proc. IEEE (Inst. Electr. Electron. Eng.); (United States) Vol. 77:2; ISSN IEEPA
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020200* -- Petroleum-- Reserves
Geology
& Exploration
DATA ANALYSIS
ELECTRICAL PROPERTIES
ELECTRICAL SURVEYS
ELECTROMAGNETIC SURVEYS
ENERGY SOURCES
EXPLORATION
GEOLOGY
GEOPHYSICAL SURVEYS
HYDROCARBONS
MAGNETOTELLURIC SURVEYS
ORGANIC COMPOUNDS
PETROLEUM GEOLOGY
PHYSICAL PROPERTIES
ROCKS
SURVEYS