Patent US3881168A successfully refreshed from Google Patents.
US3881168A
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Seismic velocity determination
Assignee: BP America Production Co
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Filing: 1973-12-11
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Granted: 1975-04-29
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Expires: 1993-12-11
Abstract
Abstract The phase delay of monofrequency seismic waves between oscillators and siesmic detectors, one located in a well and the other located near the top of the well, is measured and used to produce a log of traveltime and compressional wave velocity as a function of depth. A transducer may be attached to some part of a drill rig, supporting the pipe supplying energizing liquid to the fluidic oscillator, to produce a reference signal useful for this measurement. The receptor and reference signals are usually passed through very narrow bandpass filters to minimize noise components before the phase is determined. Since seismic wave traveltime and compressional wave velocity are related to the lithology and fluid content of the formations penetrated by the well, this information may be used diagnostically to delineate hydrocarbon accumulations and for more precise location of a drill bit or of subsurface seismic reflectors.
Inventors
- 👤 John B Farr
- 👤 Ronald W Ward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:53
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/40; G01V1/42; G01V1/28
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
131 words
A method of seismic investigation of the earth comprising the following steps carried out at a plurality of locations: a. applying at least approximately sinusoidal seismic waves to the earth by a seismic alternating source, b. receiving seismic waves from said source at a seismic receiver, one of said source and said receiver for each location being fixed at least near the surface of the earth and the other being at successively different depths in a well, and c. measuring the phase between waves received at said receiver and a reference signal derived from said source for each of said plurality of locations, one of which locations involves a source-receiver spacing of less than a wavelength, whereby the traveltime of seismic waves from said source to said receiver may be determined.
Claim 2
Independent Claim
131 words
A method of seismic investigation of the earth comprising the following steps carried out at a plurality of locations: a. applying at least approximately sinusoidal seismic waves to the earth by a seismic alternating source, b. receiving seismic waves from said source at a seismic receiver, one of said source and said receiver for each location being fixed at least near the surface of the earth and the other being at successively different depths in a well, and c. measuring the phase between waves received at said receiver and a reference signal derived from said source for each of said plurality of locations, one of which locations involves a source-receiver spacing of less than a wavelength, whereby the traveltime of seismic waves from said source to said receiver may be determined.
Claim 3
Dependent Claim
30 words
A method in accordance with claim 1 in which both said received seismic waves and said reference signal are individually narrowly filtered prior to the step of measuring said phase.
Claim 4
Dependent Claim
30 words
A method in accordance with claim 2 in which seismic waves from said source are received at a plurality of seismic receivers at least near the surface of the earth.
Claim 5
Independent Claim
101 words
A method of seismic investigation of the earth comprising the steps of: a. applying at least approximately sinusoidal seismic waves at two different frequencies to the earth at two different seismic source positions in the earth, b. receiving seismic energy from said two source positions at at least one location vertically removed from said two different source positions, and c. measuring the phase between said received seismic energy and seismic energy from each of said two source positions at each of said two different frequencies, whereby the traveltime and seismic wave velocity can be determined relative to said two source positions.
Claim 6
Independent Claim
101 words
A method of seismic investigation of the earth comprising the steps of: a. applying at least approximately sinusoidal seismic waves at two different frequencies to the earth at two different seismic source positions in the earth, b. receiving seismic energy from said two source positions at at least one location vertically removed from said two different source positions, and c. measuring the phase between said received seismic energy and seismic energy from each of said two source positions at each of said two different frequencies, whereby the traveltime and seismic wave velocity can be determined relative to said two source positions.
Claim 7
Dependent Claim
35 words
A method of seismic investigation of the earth in accordance with claim 4, including the step of narrowly filtering said received seismic energy at said two different frequencies prior to any measurement of the phase.
Claim 8
Dependent Claim
43 words
A method of seismic investigation of the earth in accordance with claim 5, including the step of repeating said phase measurements a plurality of times while changing said positions relative to said receiving location, and applying said seismic waves of different frequencies simultaneously.
Claim 9
Dependent Claim
40 words
A method of seismic investigation of the earth in accordance with claim 6 in which said receiving location is at least adjacent the top of a well penetrating the earth and said positions are adjacent each other in said well.
Claim 10
Dependent Claim
38 words
A method of seismic investigation of the earth in accordance with claim 7 in which said positions are changed by drilling said well, said positions being relatively fixed compared to the position of the bottom of said well.
Claim 11
Independent Claim
110 words
A method of seismic investigation of the earth comprising the steps of a. applying at least approximately sinusoidal seismic waves of a single frequency to the earth at a plurality of points below the surface thereof, b. receiving seismic energy from point of said application at one fixed location near the surface of the earth and vertically removed from the point of application of said waves, one of said points being less than one wavelength from said location, and c. measuring the phase between said seismic waves and the received seismic waves, whereby the traveltime and seismic wave velocity through the earth can be determined relative to said source position.
Claim 12
Independent Claim
110 words
A method of seismic investigation of the earth comprising the steps of a. applying at least approximately sinusoidal seismic waves of a single frequency to the earth at a plurality of points below the surface thereof, b. receiving seismic energy from point of said application at one fixed location near the surface of the earth and vertically removed from the point of application of said waves, one of said points being less than one wavelength from said location, and c. measuring the phase between said seismic waves and the received seismic waves, whereby the traveltime and seismic wave velocity through the earth can be determined relative to said source position.
Claim 13
Dependent Claim
63 words
A method in accordance with claim 9 in which the variation in said traveltime or said seismic wave velocity may be logged as a function of depth by receiving said energy at a plurality of fixed points near the earth''s surface and at different, vertically offset distances from the point of application, the distance between adjacent application points being less than a wavelength.
Claim 14
Dependent Claim
38 words
A method in accordance with claim 10 in which seismic energy is received at a plurality of fixed points comprising a geophone spread, the space between adjacent geophones being not greater than a fraction of said one wavelength.
Claim 15
Dependent Claim
31 words
A method in accordance with claim 9 in which the point of application of said waves varies essentially continuously from a minimum distance from the surface to a greater distance therefrom.
Claim 16
Dependent Claim
28 words
A method in accordance with claim 12 in which said point of application is adjacent to and at approximately a fixed distance from the bottom of a well.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-28 | 1978-10-28 | 1979-04-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-28 | 1982-10-28 | 1983-04-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-28 | 1986-10-28 | 1987-04-29 | $7700.00 | Window Closed / Lapsed |