US4813028A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Acoustic well logging method and apparatus
Assignee: Schlumberger Technology Corp
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Filing: 1987-07-07
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Granted: 1989-03-14
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Expires: 2007-07-07
Abstract
Abstract An acoustic well logging method and apparatus utilizes a rare earth acoustic transducer to provide low frequency acoustic energy within the borehole, and characteristics of a subsurface geological formation may be obtained, such as the formation permeability by measuring values of the attenuation of the Stoneley waves produced by the rare earth acoustic transducer.
Inventors
- 👤 Olive Y. Liu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 15:22
CPC Classifications
G; G01; G01V; G01V1/00; G01V1/40; G01V1/44; G01V1/46
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
158 words
A method for determining the permeability of a subsurface geological formation traversed by a borehole, comprising the steps of: (a) passing a logging tool through the borehole, the logging tool including a rare earth acoustic transducer; (b) generating low frequency acoustic energy at a point in the borehole using the rare earth acoustic transducer; (c) receiving acoustic signals at a plurality of receiver stations spaced one from the other and from the rare earth acoustic transducer; (d) producing full waveforms of the received signals including shear waves and Stoneley waves for the point in the borehole; (e) measuring values of the attenuation of the Stoneley wave and values of the velocity of the shear wave for the point in the borehole; and (f) combining the measured values of the Stoneley wave attenuation and the shear wave velocity with other known measured values of borehole characteristics to obtain the permeability of the formation at the point in the borehole.
Claim 2
Independent Claim
158 words
A method for determining the permeability of a subsurface geological formation traversed by a borehole, comprising the steps of: (a) passing a logging tool through the borehole, the logging tool including a rare earth acoustic transducer; (b) generating low frequency acoustic energy at a point in the borehole using the rare earth acoustic transducer; (c) receiving acoustic signals at a plurality of receiver stations spaced one from the other and from the rare earth acoustic transducer; (d) producing full waveforms of the received signals including shear waves and Stoneley waves for the point in the borehole; (e) measuring values of the attenuation of the Stoneley wave and values of the velocity of the shear wave for the point in the borehole; and (f) combining the measured values of the Stoneley wave attenuation and the shear wave velocity with other known measured values of borehole characteristics to obtain the permeability of the formation at the point in the borehole.
Claim 3
Dependent Claim
55 words
The method of claim 1, including the step of generating the low frequency acoustic energy at the point in the borehole by operating the rare earth acoustic transducer in a monopole mode, when the shear wave velocity is greater than the borehole fluid compressional velocity, to measure values of the velocity of the shear wave.
Claim 4
Dependent Claim
55 words
The method of claim 1, including the step of generating the low frequency acoustic energy at the point in the borehole by operating the rare earth acoustic transducer in a dipole mode, when the shear wave velocity is less than the borehole fluid compressional velocity, to measure values of the velocity of the shear wave.
Claim 5
Dependent Claim
18 words
The method of claim 1, including the step of operating the rare earth transducer in a dipole mode.
Claim 6
Dependent Claim
18 words
The method of claim 1, including the step of operating the rare earth transducer in a monopole mode.
Claim 7
Dependent Claim
21 words
The method of claim 1, including the step of operating the rare earth transducer in an alternating dipole and monopole mode.
Claim 8
Independent Claim
146 words
A method for obtaining waveforms indicative of the permeability of a subsurface geological formation traversed by a borehole, comprising the steps of: (a) passing a logging tool through the borehole, the logging tool (b) generating low frequency acoustic energy at a point along the borehole using the rare earth acoustic transducer; (c) receiving acoustic signals at a plurality of receiver stations spaced one from the other and from the rare earth acoustic transducer; (d) producing full waveforms of the received signals including a shear waves and Stoneley waves for the point along the borehole; and (e) recording the full waveforms an analyzing the full waveforms to determine the attenuation of the Stoneley waves and the velocity of the shear waves, said attenuation and said velocity and other known measured values of borehole characteristics further determining the permeability of said formation at said point along the borehole.
Claim 9
Independent Claim
146 words
A method for obtaining waveforms indicative of the permeability of a subsurface geological formation traversed by a borehole, comprising the steps of: (a) passing a logging tool through the borehole, the logging tool (b) generating low frequency acoustic energy at a point along the borehole using the rare earth acoustic transducer; (c) receiving acoustic signals at a plurality of receiver stations spaced one from the other and from the rare earth acoustic transducer; (d) producing full waveforms of the received signals including a shear waves and Stoneley waves for the point along the borehole; and (e) recording the full waveforms an analyzing the full waveforms to determine the attenuation of the Stoneley waves and the velocity of the shear waves, said attenuation and said velocity and other known measured values of borehole characteristics further determining the permeability of said formation at said point along the borehole.
Claim 10
Dependent Claim
15 words
The method of claim 7, wherein the full waveforms are analyzed prior to being recorded.
Claim 11
Dependent Claim
18 words
The method of claim 7, including the step of operating the rare earth transducer in a dipole mode.
Claim 12
Dependent Claim
18 words
The method of claim 7, including the step of operating the rare earth transducer in a monopole mode.
Claim 13
Dependent Claim
21 words
The method of claim 7, including the step of operating the rare earth transducer in an alternating dipole and monopole mode.
Claim 14
Dependent Claim
19 words
The method of claim 7, wherein continuous compressional wave or shear wave slowness logs are prepared from the waveforms.
Claim 15
Dependent Claim
125 words
The method of claim 1, wherein the measured values of the Stoneley wave attenuation and the shear wave velocity are combined with other known measured values of: fluid bulk modulus; shear modulus of the formation; borehole fluid density; fluid saturated formation density; acoustic signal frequency; and viscosity, in accordance with the expressions: ##EQU4## wherein a st is the Stoneley wave attenuation; a s is the formation shear wave attenuation; G is the shear modulus of the formation; B is the borehole fluid bulk modulus; V s is the formation shear wave velocity; ρ f is the pore fluid density; ρ b is the fluid saturated formation density; f is the acoustic signal frequency; n is the pore fluid viscosity; and k is the formation permeability.
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) | 1992-03-13 | 1992-09-12 | 1993-03-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-13 | 1996-09-12 | 1997-03-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-13 | 2000-09-12 | 2001-03-14 | $7700.00 | Window Closed / Lapsed |