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- Volume 6, Issue 2, 1958
Geophysical Prospecting - Volume 6, Issue 2, 1958
Volume 6, Issue 2, 1958
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RESULTS OF SUBSURFACE INVESTIGATIONS USING SEISMIC DETECTORS AND DEEP BORE HOLES*
Authors H. L. BREWER and J. HOLTZSCHERERabstractThe wells Parentis 10 and 12 which are located on the eastern edge of the Parentis anticline were found to be considerably lower at the top of the reservoir series than had been expected.
Unfortunately the village of Parentis is located in this important zone and no more seismic results could be obtained which might help locate faults and give a better picture of the area. To help in our understanding of the area, we attempted to investigate the subsurface conditions surrounding the wells by shooting shaped charges or primacord in the well and recording the returning seismic energy along profiles located on the surface. Thus far, we have used this method in three wells: Parentis 10, Parentis 12 and Lugos 2.
With the data given by a velocity survey in each well, time‐distance curves have been calculated for several typical possibilities: horizontal layers, dipping layers and the effect of a fault. A comparison of the calculated and experimental curves shows anomalies which correspond to a change of the average velocity along the travel path, which can correspond to geological changes such as: a sudden change of dip, a fault or a thickening of the section.
The anomalies have been studied on the different profiles from each well and a possible interpretation of the subsurface conditions has been given. The directions of the major accidents determined by this method are in general agreement with those found by the regular seismic shooting.
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ÉTUDE DES VITESSES DU KARROO À MADAGASCAR*
More LessAbstractThe Karroo of Madagascar is a thick continental deposit of sandstone with some shale, but no characteristic beds. Where it outcrops, velocities have been measured through bore hole surveys. It seems that they depend primarily on the age, but long refraction soundings show a progressive increase of the velocity with depth and a weak differentiation of the marker beds. These results may possibly be brought in accordance by discriminating between the present position and the deepest position of a bed through its geologic history. Thus we must admit very important erosions which, according to regional geologic data, seem possible. If we make the appropriate correction due to this distinction, all the velocity measurements fall near the curve proposed by Faust for an average shale and sand section.
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SOME PRACTICAL RESULTS OF AIRBORNE ELECTROMAGNETIC PROSPECTING IN SWEDEN*
By G. TÖRNQVISTAbstractIn 1956 a total profile length of about 10,000 kilometers was surveyed in Sweden by a new airborne electromagnetic method. The purpose of the survey was to direct ground parties to areas where conducting ore bodies (sulphides etc.) might be found and to eliminate barren ground. In this method an electromagnetic rotating field is used and the variations in both the real and imaginary components of the applied field are measured. The airborne work can be done with one plane towing a bird on a long cable or with two planes without cable connection. The two‐plane method has proved to have definite advantages over other methods, as shown by practical examples. The relation between the magnitude of the anomaly over background noise in relation to the flying altitude and the transmitter‐receiver distance is demonstrated, as well as different types of anomalies obtained. The use of this airborne method for the mapping of shallow structures in oil field terrains is discussed.
The equipment for the ensuing electromagnetic ground investigations is briefly described and examples are given of anomalies obtained.
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ĽENREGISTREMENT ÉLECTRONIQUE SIMULTANÉ DE PLUSIEURS COURBES DANS LES OPÉRATIONSDECAROTTAGE*
Authors G. MURATORI, G. MANARA and G. CHIZZONIAbstractElectronic recorders have been used for recording borehole logs since several years.
Some difficulties are however experienced in recording more than two curves at the same time.
An experimental 4 curves electronic recorder has been constructed using up to date miniaturized servomechanism components.
A general description together with performance data is given; applications of the same construction principles to pen recorders with a greater number of curves and to photographic recorders are also discussed.
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Volumes & issues
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Volume 72 (2023 - 2024)
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Volume 71 (2022 - 2023)
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Volume 70 (2021 - 2022)
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Volume 69 (2021)
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Volume 68 (2020)
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Volume 67 (2019)
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Volume 66 (2018)
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Volume 65 (2017)
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Volume 64 (2015 - 2016)
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Volume 63 (2015)
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Volume 62 (2014)
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Volume 61 (2013)
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Volume 60 (2012)
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Volume 59 (2011)
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Volume 58 (2010)
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Volume 57 (2009)
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Volume 56 (2008)
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Volume 55 (2007)
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Volume 54 (2006)
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Volume 18 (1970 - 2006)
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Volume 53 (2005)
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Volume 52 (2004)
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Volume 51 (2003)
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Volume 50 (2002)
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Volume 49 (2001)
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Volume 48 (2000)
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Volume 47 (1999)
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Volume 46 (1998)
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Volume 45 (1997)
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Volume 44 (1996)
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Volume 43 (1995)
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Volume 42 (1994)
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Volume 41 (1993)
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Volume 40 (1992)
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Volume 39 (1991)
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Volume 38 (1990)
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Volume 37 (1989)
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Volume 36 (1988)
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Volume 35 (1987)
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Volume 34 (1986)
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Volume 33 (1985)
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Volume 32 (1984)
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Volume 31 (1983)
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Volume 30 (1982)
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Volume 29 (1981)
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Volume 28 (1980)
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Volume 27 (1979)
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Volume 26 (1978)
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Volume 25 (1977)
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Volume 24 (1976)
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Volume 23 (1975)
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Volume 22 (1974)
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Volume 21 (1973)
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Volume 20 (1972)
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Volume 19 (1971)
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Volume 17 (1969)
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Volume 16 (1968)
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Volume 15 (1967)
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Volume 14 (1966)
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Volume 13 (1965)
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Volume 12 (1964)
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Volume 11 (1963)
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Volume 10 (1962)
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Volume 9 (1961)
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Volume 8 (1960)
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Volume 7 (1959)
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Volume 6 (1958)
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Volume 5 (1957)
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Volume 4 (1956)
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Volume 3 (1955)
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Volume 2 (1954)
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Volume 1 (1953)