Magnetotelluric imaging of basalt-covered sediments

Beamish, David; Travassos, Jandyr M.

doi:10.3997/1365-2397.1992018

Cited by 13 publications

(6 citation statements)

References 12 publications

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“…Their presence was modeled in other Brazilian regions as below the Parana basin (Stanley et al, 1985;Beamish and Travassos, 1992) and the Solimoes Basin (Porsani, 1991). Otherwise crustal resistivities of 200-1000 ohm.m are compatible with the figures found in other cratonic regions (Haak and Hutton, 1986;Hyndman and Shearer, 1989;Brown, 1994).…”

Section: Discussionsupporting

confidence: 73%

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Geoelectric structure beneath limestones of the Sao Francisco Basin, Brazil

Travassos

Menezes

2014

Earth Planet Sp

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A reconnaissance MT survey was conducted in the southern portion of the Sao Francisco Sedimentary Basin, Brazil, for mapping the subsurface structure. The objective was to provide a regional model and in helping to select areas to be further surveyed with seismics. The data collected at seven EMAP-style spreads of 500 m, with an average spacing of 30 km. The field procedure allowed for the correction of statics and the production of 7 inverted models, smooth representations of the regional structure as seen below each site. A 2-D forward model tested and refined the regional structure revealed by the inversions and yielded an earth composed of 4 main geologic units. A 100 ohm.m limestone layer on the top of 20 ohm.m shales, followed by a 1000-200 ohm.m structured basement. Crustal resistivities do not change until reaching depths of more than 30 km. The model ends at a conductive half-space of 30 ohm.m. A suture zone between an orogenic belt and the Sao Francisco craton was modeled below the sedimentary section bringing its know limits 60 km to the east.

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Section: Discussionsupporting

confidence: 73%

“…1. Its resistivity value is compatible to sandstone of the same Era (20 ohm.m on average) found in other Brazilian basins as the Parana (Beamish and Travassos, 1992;Stanley et al, 1985) and Solimoes basins (Porsani, 1991).…”

Section: Discussionsupporting

confidence: 58%

Geoelectric structure beneath limestones of the Sao Francisco Basin, Brazil

Travassos

Menezes

2014

Earth Planet Sp

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“…The magnetotelluric (MT) method is used for imaging subsurface structures in hydrocarbon exploration surveys especially in areas in which the reflection seismic technique shows poor quality (Orange, 1989;Beamish and Travassos, 1992;Warren and Srnka, 1992;Hoversten, 1996;Warren, 1996;Travassos and Menezes, 1999;Martini et al, 2005;Xiao and Unsworth, 2006; A C C E P T E D M A N U S C R I P T…”

Section: Introductionmentioning

confidence: 97%

Magnetotelluric signature of anticlines in Iran's Sehqanat oil field

2015

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“…Capability and usefulness of modern broadband magnetotelluric (MT) exploration as a tool for mapping structural hydrocarbon basins is mentioned by Orange (); Strack et al . (); Beamish and Travassos (); Warren and Srnka (); Hoversten (); Warren (); Travassos and Menezes (); Martini et al . (); Xiao and Unsworth (); Spratt et al .…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional modelling of magnetotelluric data to image Sehqanat hydrocarbon reservoir in southwestern Iran

Mansoori

Oskooi

Pedersen

et al. 2015

Geophysical Prospecting

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A detailed magnetotelluric survey was conducted in 2013 in the Sehqanat oil field, southwestern Iran to map the geoelectrical structures of the sedimentary Zagros zone, particularly the boundary between the Gachsaran Formation acting as cap rock and the Asmari Formation as the reservoir. According to the electrical well logs, a large resistivity contrast exists between the two formations. The Gachsaran Formation is formed by tens to hundreds of metres of evaporites and it is highly conductive (ca. 1 Ωm–10 Ωm), and the Asmari Formation consists of dense carbonates, which are considerably more resistive (more than 100 Ωm). Broadband magnetotelluric data were collected along five southwest–northeast directed parallel lines with more than 600 stations crossing the main geological trend. Although dimensionality and strike analysis of the magnetotelluric transfer functions showed that overall they satisfied local 2D conditions, there were also strong 3D conditions found in some of the sites. Therefore, in order to obtain a more reliable image of the resistivity distribution in the Sehqanat oil field, in addition to standard 2D inversion, we investigated to what extent 3D inversion of the data was feasible and what improvements in the resistivity image could be obtained. The 2D inversion models using the determinant average of the impedance tensor depict the main resistivity structures well, whereas the estimated 3D model shows significantly more details although problems were encountered in fitting the data with the latter. Both approaches resolved the Gachsaran–Asmari transition from high conductivity to moderate conductivity. The well‐known Sehqanat anticline could also be delineated throughout the 2D and 3D resistivity models as a resistive dome‐shaped body in the middle parts of the magnetotelluric profiles.

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Magnetotelluric imaging of basalt-covered sediments

Cited by 13 publications

References 12 publications

Geoelectric structure beneath limestones of the Sao Francisco Basin, Brazil

Geoelectric structure beneath limestones of the Sao Francisco Basin, Brazil

Magnetotelluric signature of anticlines in Iran's Sehqanat oil field

Three‐dimensional modelling of magnetotelluric data to image Sehqanat hydrocarbon reservoir in southwestern Iran

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