EP0105801A2
Expired / Lapsed
EP
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Well logging apparatus and method using transverse magnetic mode
Assignee: SLB NV
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Filing: 1983-09-29
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Granted: —
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Expires: 2003-09-29
Abstract
Abstract A well logging apparatus and method is disclosed which can be used as a wireline logging device or technique, and is also suitable for being employed in a logging-while-drilling device. Electromagnetic energy having primarily a transverse magnetic mode component is guided along a tubular conductor in a borehole, and measurements of the transverse magnetic mode component can be used to obtain the conductivity and/or dielectric constant of formations surrounding the borehole.
Inventors
- 👤 Brian Clark
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 14:40
CPC Classifications
G; G01; G01V; G01V3/00; G01V3/18; G01V3/30
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
68 words
A method for investigating properties of earth formations surrounding a borehole, comprising the steps of: providing a generally tubular electrically conductive body in the borehole; and characterized by generating, at a transmitter location on said body, electromagnetic energy having primarily transverse magnetic mode components which are guided by said body; and receiving the transverse magnetic mode components of the electromagnetic energy at a receiver location on the body.
Claim 2
Independent Claim
68 words
A method for investigating properties of earth formations surrounding a borehole, comprising the steps of: providing a generally tubular electrically conductive body in the borehole; and characterized by generating, at a transmitter location on said body, electromagnetic energy having primarily transverse magnetic mode components which are guided by said body; and receiving the transverse magnetic mode components of the electromagnetic energy at a receiver location on the body.
Claim 3
Dependent Claim
34 words
The method as defined by claim 1 characterized by the step of determining the conductivity and/or permittivity of said surrounding earth formations as a function of the amplitude and phase of the received energy.
Claim 4
Dependent Claim
29 words
The method as defined by claim 1 or 2 characterized in that said receiving step comprises receiving said energy at a pair of spaced receivers within the receiver location.
Claim 5
Dependent Claim
21 words
The method as defined by claim 1, 2, or 3 characterized in that the transmitted energy is made variable in frequency.
Claim 6
Independent Claim
32 words
The method as defined by any one of the previous claims characterized in that the frequency of the transmitted energy is selected in the range of about 10 megahertz to 30 megahertz.
Claim 7
Independent Claim
45 words
The method as defined in any one of the previous claims characterized by providing said generally tubular electrically conductive body as part of the drill string of a drilling system; and communicating signals, which depend on the received energy, to the surface of the earth.
Claim 8
Dependent Claim
98 words
Apparatus for investigating properties of earth formations surrounding a borehole, comprising: a logging device moveable through the borehole, said device including a generally tubular electrically conductive body portion; energizing means; and characterized by transmitting antenna means, mounted on said logging device and coupled to said energizing means, for generating electromagnetic energy having primarily transverse magnetic components; and receiving antenna means, mounted on said logging device in spaced relation to said transmitting antenna means, for receiving the transmitted electromagnetic energy, said receiving antenna means being adapted to be primarily sensitive to the transverse magnetic mode components of electromagnetic energy.
Claim 9
Dependent Claim
98 words
Apparatus for investigating properties of earth formations surrounding a borehole, comprising: a logging device moveable through the borehole, said device including a generally tubular electrically conductive body portion; energizing means; and characterized by transmitting antenna means, mounted on said logging device and coupled to said energizing means, for generating electromagnetic energy having primarily transverse magnetic components; and receiving antenna means, mounted on said logging device in spaced relation to said transmitting antenna means, for receiving the transmitted electromagnetic energy, said receiving antenna means being adapted to be primarily sensitive to the transverse magnetic mode components of electromagnetic energy.
Claim 10
Dependent Claim
35 words
Apparatns as defined by claim 7 characterized by means coupled to said receiving means for determining the conductivity and/or permittivity of said surrounding earth formations as a function of the output of said receiver means.
Claim 11
Dependent Claim
24 words
Apparatus as defined by claim 7 or 8 characterized in that said transmitting antenna means and said receiving antenna means canprise toroidal solenoid antennas.
Claim 12
Dependent Claim
23 words
Apparatus as defined by claim 9 characterized in that said toroidal solenoid antennas are recessed in generally annular slots in said logging device.
Claim 13
Dependent Claim
24 words
Apgaratus as defined by any one of claims 7 to 10 characterized in that said receiver antennas means comprises a pair of spaced antennas.
Claim 14
Dependent Claim
33 words
Apparatus as defined by any one of claims 7 to 11 characterized in that said energizing means includes means for varying the frequency of the energizing signal applied to said transmitting antenna means.
Claim 15
Dependent Claim
30 words
Apparatus as defined by any one of claims 7 to 12 characterized in that said energizing means is operative in the frequency range of about 10 megahertz to 30 megahertz.
Claim 16
Dependent Claim
50 words
Apparatus as defined in any one of claims 7 to 13 characterized in that the electrically conductive generally tubular body is mounted downhole on the drill string of a drilling system; and characterized by means for commmicating signals derived from said receiving antenna means to the surface of the earth.
References Cited (Backward Citations)
No citation records indexed.
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