Patent US4587423A successfully refreshed from Google Patents.
US4587423A
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US
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Method for gravel pack evaluation
Assignee: Schlumberger Technology Corp
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Filing: 1984-07-31
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Granted: 1986-05-06
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Expires: 2004-07-31
Abstract
Abstract Based on Monte Carlo modeling of gravel pack conditions in a completed borehole, a straightforward expression for the determination of percent packing as a function of known or measurable borehole quantities is derived, from which an accurate quantitative gravel pack log may be obtained for purposes of evaluating gravel pack quality. The method includes using a logging tool with a gamma source and gamma detector.
Inventors
- 👤 James R. Boyce
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:44
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04; G01V5/08; G01V5/12; E; E21; E21B; E21B43/00; E21B43/02; E21B43/04; E21B47/00
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
228 words
A method for investigating a gravel pack located in the annulus between the tubing/screen and the casing of a borehole, comprising the steps of: moving a logging tool, including a gamma ray source and at least one gamma ray detector, through the tubing/screen over the depth region of the gravel pack; deriving a measurement (N' T ,S) of the number of gamma rays detected by said detector over a predetermined time interval; and determining the percent packing (P) of the gravel pack at the depth of measurement in accordance with the relationship: ##EQU4## where ##EQU5## ρ f and ρ m are the density of the fluid and the material, respectively, in the annulus between the tubing/screen and the casing of the borehole; v' f is the volume fraction of the fluid in the annulus between the tubing/screen and the casing of the borehole; A' T ,S is a previously determined constant A' T or A' S depending upon whether the depth of measurement is opposite the tubing or the screen; B' T ,S is a previously determined constant B' T or B' S depending upon whether the depth of measurement is opposite the tubing or the screen; and N' T ,S is said measured number of detected gamma rays N' T or N' S depending upon whether the depth of measurement is opposite the tubing or the screen.
Claim 2
Independent Claim
228 words
A method for investigating a gravel pack located in the annulus between the tubing/screen and the casing of a borehole, comprising the steps of: moving a logging tool, including a gamma ray source and at least one gamma ray detector, through the tubing/screen over the depth region of the gravel pack; deriving a measurement (N' T ,S) of the number of gamma rays detected by said detector over a predetermined time interval; and determining the percent packing (P) of the gravel pack at the depth of measurement in accordance with the relationship: ##EQU4## where ##EQU5## ρ f and ρ m are the density of the fluid and the material, respectively, in the annulus between the tubing/screen and the casing of the borehole; v' f is the volume fraction of the fluid in the annulus between the tubing/screen and the casing of the borehole; A' T ,S is a previously determined constant A' T or A' S depending upon whether the depth of measurement is opposite the tubing or the screen; B' T ,S is a previously determined constant B' T or B' S depending upon whether the depth of measurement is opposite the tubing or the screen; and N' T ,S is said measured number of detected gamma rays N' T or N' S depending upon whether the depth of measurement is opposite the tubing or the screen.
Claim 3
Dependent Claim
23 words
The method of claim 1 further comprising the step of recording the percent packing determination as a function of depth within the borehole.
Claim 4
Independent Claim
224 words
A method for investigating a gravel pack located in the annulus between the tubing/screen and the casing of a borehole, comprising the steps of: deriving a measurement (N' T ,S) of the number of gamma rays detected in a predetermined time interval by a gamma ray detector located within the tubing/screen as a result of irradiation of the borehole by a gamma ray source located within the tubing/screen; and determining the percent packing (P) of the gravel pack at the depth of measurement in accordance with the relationship: ##EQU6## where ##EQU7## ρ f and ρ m are the density of the fluid and the material, respectively, in the annulus between the tubing/screen and the casing of the borehole; v' f is the volume fraction of the fluid in the annulus between the tubing/screen and the casing of the borehole; A' T ,S is a previously determined constant A' T or A' S depending upon whether the depth of measurement is opposite the tubing or the screen; B' T ,S is a previously determined constant B' T or B' S depending upon whether the depth of measurement is opposite the tubing or the screen; and N' T ,S is said measured number of detected gamma rays N' T or N' S depending upon whether the depth of measurement is opposite the tubing or the screen.
Claim 5
Independent Claim
224 words
A method for investigating a gravel pack located in the annulus between the tubing/screen and the casing of a borehole, comprising the steps of: deriving a measurement (N' T ,S) of the number of gamma rays detected in a predetermined time interval by a gamma ray detector located within the tubing/screen as a result of irradiation of the borehole by a gamma ray source located within the tubing/screen; and determining the percent packing (P) of the gravel pack at the depth of measurement in accordance with the relationship: ##EQU6## where ##EQU7## ρ f and ρ m are the density of the fluid and the material, respectively, in the annulus between the tubing/screen and the casing of the borehole; v' f is the volume fraction of the fluid in the annulus between the tubing/screen and the casing of the borehole; A' T ,S is a previously determined constant A' T or A' S depending upon whether the depth of measurement is opposite the tubing or the screen; B' T ,S is a previously determined constant B' T or B' S depending upon whether the depth of measurement is opposite the tubing or the screen; and N' T ,S is said measured number of detected gamma rays N' T or N' S depending upon whether the depth of measurement is opposite the tubing or the screen.
Claim 6
Dependent Claim
24 words
The method of claim 3 further comprising the step of recording the percent packing determination as a function of the depth within the borehole.
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) | 1989-05-05 | 1989-11-04 | 1990-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-05 | 1993-11-04 | 1994-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-05 | 1997-11-04 | 1998-05-06 | $7700.00 | Window Closed / Lapsed |