Intra-basalt units and base of the volcanic succession east of the Faroe Islands exemplified by interpretation of offshore 3D seismic data

TY - JOUR

T1 - Intra-basalt units and base of the volcanic succession east of the Faroe Islands exemplified by interpretation of offshore 3D seismic data

AU - Ellefsen, M.

AU - Boldreel, L. O.

AU - Larsen, M.

PY - 2010/12/1

Y1 - 2010/12/1

N2 - Recent exploration activities in the basalt covered part of the offshore Faroe Island region has stressed the need for a better understanding of the volcanic succession, especially the lowermost part and the transition to the underlying non-volcanic succession. Using the proposed interpretation methods, which include careful identification of inclined reflector segments and flattening to various reflectors representing pronounced continuous markers embedded horizontally and 3D visualization, six volcanic units have been identified. The upper three units consist of plane-parallel reflector packages and probably represent subaerially extruded lava flows. The three lower units are characterized by irregular hummocky and inclined reflectors and are interpreted as lava deltas composed mainly of hyaloclastites. Within the data coverage area, the direction of extrusion is inferred from the seismic interpretation and four units originate from the NW and two from the SE. It is believed that the base of the volcanic succession is situated at a deeper level than the base of the parallel bedded units. At the base of the basalt succession and in the lower part of the volcanic succession pronounced reflector segments are ascribed to saucer-shaped sills. Analysing the seismic data using principles of seismic stratigraphy and observing them in a 3D environment, it is possible to obtain a broader understanding of the volcanic succession in the area and thereby divide the volcanic succession into characteristic facies units and separate it from the non-volcanic lithology and sills. The study shows that applying the proposed interpretation technique allows an evolution model to be put forward and it is suggested that the approach used in the study can be of use for hydrocarbon exploration in other basalt-covered areas.

AB - Recent exploration activities in the basalt covered part of the offshore Faroe Island region has stressed the need for a better understanding of the volcanic succession, especially the lowermost part and the transition to the underlying non-volcanic succession. Using the proposed interpretation methods, which include careful identification of inclined reflector segments and flattening to various reflectors representing pronounced continuous markers embedded horizontally and 3D visualization, six volcanic units have been identified. The upper three units consist of plane-parallel reflector packages and probably represent subaerially extruded lava flows. The three lower units are characterized by irregular hummocky and inclined reflectors and are interpreted as lava deltas composed mainly of hyaloclastites. Within the data coverage area, the direction of extrusion is inferred from the seismic interpretation and four units originate from the NW and two from the SE. It is believed that the base of the volcanic succession is situated at a deeper level than the base of the parallel bedded units. At the base of the basalt succession and in the lower part of the volcanic succession pronounced reflector segments are ascribed to saucer-shaped sills. Analysing the seismic data using principles of seismic stratigraphy and observing them in a 3D environment, it is possible to obtain a broader understanding of the volcanic succession in the area and thereby divide the volcanic succession into characteristic facies units and separate it from the non-volcanic lithology and sills. The study shows that applying the proposed interpretation technique allows an evolution model to be put forward and it is suggested that the approach used in the study can be of use for hydrocarbon exploration in other basalt-covered areas.

KW - 3D seismic data

KW - Basalts

KW - Facies interpretation

KW - Faroe Islands

KW - Hyaloclastites

KW - Volcanics

UR - http://www.scopus.com/inward/record.url?scp=80052533448&partnerID=8YFLogxK

U2 - 10.1144/0071033

DO - 10.1144/0071033

M3 - Journal article

AN - SCOPUS:80052533448

SN - 2047-9921

VL - 7

SP - 1033

EP - 1042

JO - Petroleum Geology Conference Proceedings

JF - Petroleum Geology Conference Proceedings

IS - 0

ER -