US3898610A
Expired / Lapsed
US
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Method for prediction of abnormal pressures from routine or special seismic records
Assignee: ExxonMobil Upstream Research Co
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Filing: 1969-09-22
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Granted: 1975-08-05
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Expires: 1989-09-22
Abstract
Abstract A technique for determining depth of highly pressurized formations wherein a seismic observation is performed to produce a multitrace seismogram, reflection events thereon are identified, the average velocities and the interval velocities are determined from reflection events on the seismogram, and deviation from a ''''normal'''' velocity function is used to determine depth and degree of abnormality of high pressure formations. Specific gravity of earth cuttings is measured while drilling a borehole, and deviations from the normal are used to further locate such formations.
Inventors
- 👤 Jr Eugene S Pennebaker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 09:18
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/28; G01V1/30
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
87 words
A method for detecting abnormally pressured earth formations comprising: performing a seismic observation at the earth''s surface in which seismic waves are generated at the earth''s surface and seismic energy resulting from said seismic waves so generated is detected at the earth''s surface to obtain average seismic velocities through earth formations beneath the location of said seismic observation; and utilizing variations between the average seismic velocities in abnormally pressured formations and average seismic velocities in normally pressured formations to determine the depth of said abnormally pressured formations.
Claim 2
Independent Claim
87 words
A method for detecting abnormally pressured earth formations comprising: performing a seismic observation at the earth''s surface in which seismic waves are generated at the earth''s surface and seismic energy resulting from said seismic waves so generated is detected at the earth''s surface to obtain average seismic velocities through earth formations beneath the location of said seismic observation; and utilizing variations between the average seismic velocities in abnormally pressured formations and average seismic velocities in normally pressured formations to determine the depth of said abnormally pressured formations.
Claim 3
Dependent Claim
27 words
A method as recited in claim 1 in whIch the average seismic velocities in normally pressured formations are given by a relationship which increases exponentially with depth.
Claim 4
Dependent Claim
26 words
A method as recited in claim 1 including obtaining indications of the magnitude of the abnormal pressures from the amount of said average seismic velocity variations.
Claim 5
Independent Claim
95 words
A method for detecting abnormally pressured earth formations comprising: performing a seismic observation over an area of the earth''s surface in which seismic waves are generated at the earth''s surface and seismic energy resulting from said seismic waves so generated is detected at the earth''s surface; obtaining average seismic interval travel times through earth formations beneath said area of said earth''s surface; and utilizing variations between the average seismic interval travel times in abnormally pressured formations and average seismic interval travel times in normally pressured formations to determine the depth of said abnormally pressured formations.
Claim 6
Independent Claim
95 words
A method for detecting abnormally pressured earth formations comprising: performing a seismic observation over an area of the earth''s surface in which seismic waves are generated at the earth''s surface and seismic energy resulting from said seismic waves so generated is detected at the earth''s surface; obtaining average seismic interval travel times through earth formations beneath said area of said earth''s surface; and utilizing variations between the average seismic interval travel times in abnormally pressured formations and average seismic interval travel times in normally pressured formations to determine the depth of said abnormally pressured formations.
Claim 7
Dependent Claim
29 words
A method as recited in claim 4 in which the average seismic interval travel times in normally pressured formations are given by a relationship which decreases exponentially with depth.
Claim 8
Dependent Claim
48 words
The method of claim 4 wherein the seismic interval travel times in normally pressured formations are given by the relationship Log10 V Log10 Vo + KD where Vo is seismic wave velocity at datum depth, D is depth in the earth, and K is between 0.000027 and 0.000031.
Claim 9
Dependent Claim
24 words
A method as recited in claim 4 in which the amount of said interval travel time deviation indicates the magnitude of the abnormal pressure.
Claim 10
Dependent Claim
65 words
A method as recited in claim 4 including the steps of preparing an average seismic interval travel time curve as a function of depth for normally pressured formations and comparing said curve with said average seismic interval travel times in said earth formations beneath the location of said seismic observation plotted as a function of depth to determine the depth of said abnormally pressured formations.
Claim 11
Independent Claim
140 words
A method for locating abnormally pressured earth formations comprising: conducting a seismic observation at the earth''s surface in which seismic waves are generated at the earth''s surface and seismic energy resulting from said seismic waves so generated is detected at the earth''s surface to produce a seismogram indicative of average travel times of seismic waves through earth formations beneath the location of said observation; identifying lineups of events produced by reflected seismic waves on said seismogram; measuring the average velocity of reflected seismic waves which produce each of said lineups of events; recording the velocity thus measured as a function of depth of the reflecting horizons; and comparing said recording with a recording of normal seismic wave velocity through normally pressured formations as a function of depth to determine any deviation between the recordings indicative of abnormally pressured earth formations.
Claim 12
Independent Claim
140 words
A method for locating abnormally pressured earth formations comprising: conducting a seismic observation at the earth''s surface in which seismic waves are generated at the earth''s surface and seismic energy resulting from said seismic waves so generated is detected at the earth''s surface to produce a seismogram indicative of average travel times of seismic waves through earth formations beneath the location of said observation; identifying lineups of events produced by reflected seismic waves on said seismogram; measuring the average velocity of reflected seismic waves which produce each of said lineups of events; recording the velocity thus measured as a function of depth of the reflecting horizons; and comparing said recording with a recording of normal seismic wave velocity through normally pressured formations as a function of depth to determine any deviation between the recordings indicative of abnormally pressured earth formations.
Claim 13
Dependent Claim
22 words
A method as recited in claim 9 in which the amount of deviation in velocities indicates the magnitude of the abnormal pressure.
Claim 14
Independent Claim
145 words
A method for detecting abnormally pressured earth formations comprising: performing a seismic observation at the earth''s surface in which seismic waves are generated at the earth''s surface and seismic energy resulting from said seismic waves so generated is detected at the earth''s surface to obtain average seismic velocities through earth formations beneath the location of said seismic observation at least to a particular depth, which earth formations include normally pressured and abnormally pressured formations; producing from said average seismic velocities a first curve representing average seismic interval travel times in said normally pressured and abnormally pressured formations versus depth; producing a second curve represEnting putatively normal average seismic interval travel times in normally pressured formations extending at least to said particular depth versus depth; and obtaining the deviations of said first curve from said second curve to establish the depths of said abnormally pressured formations.
Claim 15
Independent Claim
145 words
A method for detecting abnormally pressured earth formations comprising: performing a seismic observation at the earth''s surface in which seismic waves are generated at the earth''s surface and seismic energy resulting from said seismic waves so generated is detected at the earth''s surface to obtain average seismic velocities through earth formations beneath the location of said seismic observation at least to a particular depth, which earth formations include normally pressured and abnormally pressured formations; producing from said average seismic velocities a first curve representing average seismic interval travel times in said normally pressured and abnormally pressured formations versus depth; producing a second curve represEnting putatively normal average seismic interval travel times in normally pressured formations extending at least to said particular depth versus depth; and obtaining the deviations of said first curve from said second curve to establish the depths of said abnormally pressured formations.
Claim 16
Dependent Claim
22 words
A method as described in claim 11 including measuring the magnitudes of the abnormal pressures from the magnitudes of said obtained deviations.
References Cited (Backward Citations)
US3235026A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |