ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01720.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractMajor savings for operators of seismic parties have been achieved by the use of prilled ammonium nitrate as a substitute for gelatin dynamite in areas where shot holes are dry. Pound for pound, the prills appear to have the same energy yield as 60% gelatin dynamite, and some improvement of records has been noted where prills are used. Safety problems are less with ammonium nitrate than with dynamite, and the development of efficient field handling techniques prevents the loss of production.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01449.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractConventional or continuous velocity logging generally fail to solve the problem of velocities in the whole area of a seismic survey. Surface measurements often bring a large amount of additional information: effect of shallow layers, change of facies, correlations. The authors present a theoretical view on the physical meaning of interval velocities. After a short synthesis of the diverse formulae formerly proposed (Faust, West), the practical manner of using these formulae and the accurate interpretation obtained with the help of geological and geophysical data are shown. Several characteristical examples are finally explained and commented on.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01450.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractUsing a resonance method, determinations have been made of the longitudinal bar velocity and of Poisson's ratio of thirteen different chemically pure limestones. The relation between the velocity and the density showed far less scatter than in the determinations previously published; this is primarily attributed to the high purity of the specimens used. The measurements further showed a tendency of the values of Poisson's ratio to increase with increasing density.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01451.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractA method is described in which the major part of gravimetric terrain corrections may be estimated by digital computing methods.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01452.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractSome mathematical inequalities are proved and their relevance to the interpretation of local magnetic and gravity anomalies is discussed. They can be applied to the readings of either a vertical magnetometer or a total field magnetometer or a gravimeter and yield a maximum possible value for the depth below the earth's surface of the top surface of the body producing the anomaly.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01453.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractThe electric and magnetic field of a direct‐current element, embedded in a space consisting of two halfspaces differing in conductivity and permeability, is given in a form suitable for integration along a cable. From these formulae is obtained the field when one end of a D.C. cable is grounded in a highly conducting, pencilformed ore body, considered as a line electrode with uniform current leakage. Numerical examples are given for a horizontal line electrode. The formulae should be useful as a first approximation to the A.C. case. The validity of this is shortly discusse

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01454.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractAn analogy is established between the propagation of an electromagnetic field in a horizontally stratified conductive medium and that of currents in a linear electric network. This analogy will allow us to know in which case measurements executed at the surface of the ground can provide information about the properties of deeper layers. The situation is the same as when one tries, by means of impedance measurements at the input terminals, to know the properties of electric lines or lumped networks.A symmetrical linear network establishes between:VoltagesV1andV2(respectively at input and output terminals)CurrentsI1andI2(respectively at input and output terminals), the relationshipis called the “phase constant” andZthe characteristic impedance The tableis called “characteristic matrix”If one then takes the horizontal components of an electromagnetic field, one can compare the voltageVwith the horizontal electric fieldE(in voltsm‐1) and the currentIwith the horizontal magnetic fieldH(in Ampm−1)For plane waves in vacuum, one gets (Schelkunoff)Z=C(velocity of light)A layer whose thickness isDhas a phase constant⌈= 2 πD/λ (λ= wavelength)For plane waves in a conductive, non magnetic medium whose conductivity is δ, one getsFor the system of waves created by a point‐source one expresses the solution, since it is classical, as a sum or integral of differentmodes. For each of these modes, one can still write a bilinear relationship similar to (1), and calculateZand ⌈.A generalization of this result is given.Boundary conditions that exist at the surfaces of separation are met by writing the continuity ofEandH. This condition exactly corresponds to the fact that there oneVand oneIat the junctions of various sections of lines, or networks.The characteristic matrix of a cascade of networks‐or here that of a horizontally stratified ground– is the product of the matrixes of each network. If, in addition, one knows the end impedance–here the conductivity λnof the last layer, supposed to be infinite–one can compute the input impedanceReof the whole system. In electromagnetic prospecting, it isRethat conditions the observable field.Inversely, if measurements were infinitely accurate, the. knowledge of the surface field would give all the thicknessesDand conductivities δ of intermediate layers, in the same way that impedance measurements at the input terminals of a cable would allow to locate any failure. The imperfection of measurements causes the elements located too far away (from the point of view of wave a

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01455.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

ABSTRACTA new logging method, which makes use of specific chemical reactions to locate petroleum or other minerals has been developed. The method has been named “Differential Electric Log” (CED).In this paper the application to the CED method of redox (reduction/oxidation) reactions is discussed. A series of organic oxidants was found, capable of undergoing reaction with crude oil, sulphur, mineral sulphides, lignite. A small amount of an oxidant of this type is added to the drilling fluid and pumped into the borehole where reaction takes place in correspondence with layers containing oxidizable minerals. TwoSPlogs, recorded before and after the oxidation, are compared and the presence of such minerals is thus detected.A theoretical hypothesis explaining the mechanism of the potential change due to the chemical reaction is proposed both in the case of electronically conducting and non conducting minerals. The influence of redox potential onSPis discussed.The results of laboratory experiments on several different oxidizable ores and those of field tests performed on pyrite, lignite, and oil wells are reported on and discussed on the basis of the theoretical hypothesis propo

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01456.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

AbstractIn nine small areas in the Black Forest measurements were made of theCO2content of ground air, using a method which is based on the difference in heat conductivity betweenCO2on one side andN2andO2on the other. Measurements during four days yielded four strongCO2anomalies. At one of these a well was sunk, which gave a considerable discharge of mineral water.

ISSN:0016-8025    

DOI:10.1111/j.1365-2478.1959.tb01457.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY