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US 4,899,112 AGranted
Well logging apparatus and method for determining formation resistivity at a shallow and a deep depth
AssigneeSchlumberger Technology Corporation
InventorsBrian Clark, Jacques Jundt, Martin Luling, Michael O. Ross
Life of this patent
Estimating the term…
Abstract
Well logging techniques and apparatus are disclosed for determining formation resistivity at different radial depths of investigation and with greater accuracy than prior techniques, for determining the existence, locations and properties of beds and caves, and for determining changes in the size of a borehole.
Claims67
Apparatus for determining the resistivity of earth formations surrounding a borehole, comprising;
- means for generating electromagnetic wave energy at a first location in the borehole;
- means for receiving electromagnetic wave energy at second and third locations in the borehole, said second and third locations being successively spaced longitudinally in the borehole from said first location;
- means for detecting the phase shift between electromagnetic energy received at said second and third locations in the borehole;
- means for detecting the attenuation between electromagnetic energy received at said second and third locations in the borehole;
- means for determining, as a function of the detected phase shift, the resistivity of formations at a relatively shallow depth of investigation around said second and third locations;
- and
- means for determining, as a function of the detected attenuation, the resistivity of formations at a relatively deep depth of investigation around said second and third locations.
4 more elements
Apparatus for determining the resistivity of formations surrounding a borehole, comprising:
- a logging device adapted for movement through a borehole,
- upper and lower spaced transmitter means formed in said logging device;
- upper and lower spaced receiver means formed in said logging device between said transmitter means on a substantially common axis therewith;
- means for alternately energizing said transmitter means with electromagnetic energy;
- means for detecting the phase shift and the attenuation between energy received at the two receiver means during energizing of the upper transmitter means;
- means for detecting the phase shift and the attenuation between energy received at the two receiver means during energizing of the lower transmitter means;
- means for determining, as a function of both detected phase shifts, the resistivity of formations at a relatively shallow depth of investigation around the receiver means;
- and
- means for determining, as a function of both detected attenuations, the resistivity of formations at a relatively deep depth of investigation around the receiver means.
6 more elements
Apparatus for determining changes in the size of a borehole in earth formations, comprising:
- a logging device adapted for movement generally through a borehole,
- upper and lower spaced transmitter means formed in said logging device;
- upper and lower spaced receiver means formed in said logging device between said transmitter means on a substantially common axis therewith;
- means for alternately energizing said transmitter means;
- means for detecting the phase shift between energy received at the lower receiver means and energy received at the upper receiver means during energizing of the upper transmitter means, and for generating an upper phase shift output signal therefrom;
- means for detecting the phase shift between energy received at the upper receiver means and the energy received at the lower receiver means during energizing of the lower transmitter means, and for generating a lower phase shift output signal therefrom;
- and
- means responsive to said upper phase shift output signal and said lower phase shift output signal for generating a phase shift imbalance signal that is indicative of a change in borehole size in the region of said receiver means.
5 more elements
Apparatus for determining changes in the size of a borehole in earth formations, comprising:
- a logging device adapted for movement generally through a borehole,
- upper and lower spaced transmitter means formed in said logging device;
- upper and lower spaced receiver means formed in said logging device between said transmitter means on a substantially common axis therewith;
- means for alternately energizing said transmitter means;
- means for detecting the attenuation between energy received at the lower receiver means and energy received at the upper receiver means during energizing of the upper transmitter means, and for generating an upper attenuation output signal therefrom;
- means for detecting the attenuation between energy received at the upper receiver means and the energy received at the lower receiver means during energizing of the lower transmitter means, and for generating a lower attenuation output signal therefrom;
- and
- means responsive to said upper attenuation output signal and said lower attenuation output signal for generating an attenuation imbalance signal that is indicative of a change in borehole size in the region of said receiver means.
5 more elements
A method for determining the resistivity of earth formations surrounding a borehole, comprising the steps of:
- generating electromagnetic wave energy at a first location in the borehole;
- receiving electromagnetic wave energy at second and third locations in the borehole, said second and third locations being successively spaced longitudinally in the borehole from said first location;
- detecting the phase shift between electromagnetic energy received at said second and third locations in the borehole;
- detecting the attenuation between electromagnetic energy received at said second and third locations in the borehole;
- determining, as a function of the detected phase shift, the resistivity of formations at a relatively shallow depth of investigation around said second and third locations;
- and determining, as a function of the detected attenuation, the resistivity of formations at a relatively deep depth of investigation around said second and third locations.
3 more elements
A method for determining the resistivity of formations surrounding a borehole, comprising the steps of:
- providing a logging device which is movable through a borehole, the logging device having upper and lower spaced transmitters and upper and lower spaced receivers between the transmitters;
- alternately energizing said transmitters with electromagnetic energy;
- detecting the phase shift and the attenuation between energy received at the two receivers during energizing of the upper transmitter;
- detecting the phase shift and the attenuation between energy received at the two receivers during energizing of the lower transmitter;
- determining, as a function of both detected phase shifts, the resistivity of formations at a relatively shallow depth of investigation around the receivers;
- and
- determining, as a function of both detected attenuations, the resistivity of formations at a relatively deep depth of investigation around the receivers.
4 more elements
A method for determining changes in the size of a borehole in earth formations, comprising the steps of:
- transmitting energy alternately from upper and lower spaced transmitter locations in the borehole;
- receiving said energy at upper and lower spaced receiver locations between the transmitter locations;
- detecting the phase shift between energy received at the lower receiver location and energy received at the upper receiver location during transmission from the upper transmitter location, and generating an upper phase shift output signal therefrom;
- detecting the phase shift between energy received at the upper receiver location and energy received at the lower receiver location during transmission from the lower transmitter location, and generating a lower phase shift output signal therefrom;
- and
- generating a phase shift imbalance signal in response to said upper phase shift output signal and said lower phase shift output signal, said phase shift imbalance signal being indicative of a change in borehole size in the region of said receiver locations.
3 more elements
A method for determining changes in the size of a borehole in earth formations, comprising the steps of:
- transmitting energy alternately from upper and lower spaced transmitter locations in the borehole;
- receiving said energy at upper and lower spaced receiver locations between the transmitter locations;
- detecting the attenuation between energy received at the lower receiver location and energy received at the upper receiver location during transmission from the upper transmitter location, and generating an upper attenuation output signal therefrom;
- detecting the attenuation between energy received at the upper receiver location and energy received at the lower receiver location during transmission from the lower transmitter location, and generating a lower attenuation output signal therefrom;
- and
- generating an attenuation imbalance signal in response to said upper attenuation output signal and said lower attenuation output signal, said attenuation imbalance signal being indicative of a change in borehole size in the region of said receiver locations.
3 more elements
Dependencies are inferred from the claim text.