Authors / CoAuthors
Abstract
Delhi-Santos Gidgealpa No. 1 Well was drilled in the north-eastern corner of South Australia by Delhi Australian Petroleum Ltd, as operator, and Santos Limited. The well is 60 miles south-west of Innamincka No. 1 and 50 miles west-north-west of Dullingari No. 1. Gidgealpa No. 1 was spudded on 28th August, 1963, reached a total depth of 13,114 feet on 27th November, 1963, and was completed as a water well flowing from the Mooga Sandstone on 6th December, 1963. A National 80-B rig, owned and operated by Drilling Contractors (Australia) Pty Ltd, was used to drill the well. Gidgealpa No. 1 was drilled as an off-structure well on the flank of a prominent closed anticline. The Mesozoic sequence was the thickest yet encountered in wells in the western part of the Great Artesian Basin, and very similar to that found in Innamincka No. 1. The overall lithology of the Permian in Gidgealpa No. 1 resembles that in Dullingari No. 1 although detailed correlation is not possible. Below the regional angular unconformity at the base of the Permian, a thick sequence of Cambrian marine carbonates and tuffaceous sediments was penetrated. This was the first encounter of Cambrian rocks in the subsurface of the Great Artesian Basin. More hydrocarbon shows were encountered in the Permian sequence in this well than in any other drilled to date in this region. Unfortunately the sandstones exhibited very low porosity. A deep zone of porous dolomite, some 400 feet thick, was also discovered in the Middle Cambrian, and on test, flowed very gassy saltwater. Thus Delhi-Santos Gidgealpa No. I, in addition to providing much new geological information, gave most encouraging indications that, under favourable conditions, the Permian and the newly discovered Middle Cambrian dolomite could produce hydrocarbons. The off-structure drilling operation at Delhi-Santos Gidgealpa No. 1 was subsidized under the Petroleum Search Subsidy Act 1959-1961, from surface to total depth.
Product Type
document
eCat Id
67345
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
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2601
Australia
Keywords
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- GA PublicationOther Publication
- ( Theme )
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- petroleum exploration
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- AU-SA
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_External
Publication Date
1966-01-01T00:00:00
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unknown
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geoscientificInformation
Series Information
PSSA_73
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