US4493998A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for monitoring drilling materials for gamma ray activity
Assignee: Halliburton Co
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Filing: 1982-04-02
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Granted: 1985-01-15
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Expires: 2002-04-02
Abstract
Abstract In the preferred and illustrated embodiment taught herein, method steps for monitoring of raw materials to be used in drilling mud are disclosed. The materials are monitored for radioactivity. Procedures for taking such measurements are disclosed, and the extent of gamma radioactivity in the raw materials used in drilling mud is determined. This is correlated to the increased radiation attributable to mud made from these materials and the effect the mud would have on gamma ray measuring logs. An alternate procedure for testing drilling mud, typically at the well site, is also disclosed. The method detects mud radioactivity from any additives including barite, potassium chloride, well cuttings or others. Excessive background levels due to mud gamma radioactivity in a well may very well mask the data obtained by various logging procedures dependent on gamma radiation. Procedures are also described for either rejecting mud which is too radioactive or correcting the log measurements for mud effects.
Inventors
- 👤 Harry D. Smith, Jr.
- 👤 Dan M. Arnold
- 👤 Ward E. Schultz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:27
CPC Classifications
G; G01; G01V; G01V5/00; G01V5/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
134 words
A method of quantitatively determining the amount of background gamma ray radioactivity which would be detected in a gamma ray sensitive logging tool in a wellbore due to the presence of naturally occurring radioactive materials in drilling fluid comprising the steps of: (a) placing a sized sample of drilling fluid in a container; (b) positioning a sensor means in said container at a position where said sensor means is exposed to gamma radiation from said sample to form an output indicative of gamma ray radioactivity of said sample; and (c) converting said sensor means output according to a predetermined functional relationship into an output value indicative of the gamma radiation background which the drilling fluid would induce in a gamma ray measuring logging device as a function of drilling fluid density and wellbore diameter.
Claim 2
Independent Claim
134 words
A method of quantitatively determining the amount of background gamma ray radioactivity which would be detected in a gamma ray sensitive logging tool in a wellbore due to the presence of naturally occurring radioactive materials in drilling fluid comprising the steps of: (a) placing a sized sample of drilling fluid in a container; (b) positioning a sensor means in said container at a position where said sensor means is exposed to gamma radiation from said sample to form an output indicative of gamma ray radioactivity of said sample; and (c) converting said sensor means output according to a predetermined functional relationship into an output value indicative of the gamma radiation background which the drilling fluid would induce in a gamma ray measuring logging device as a function of drilling fluid density and wellbore diameter.
Claim 3
Dependent Claim
32 words
The method of claim 1 wherein said drilling fluid sample is placed in the container to a specified depth and said sensor means is placed in a predetermined position in the container.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein said sample contains particulate barite.
Claim 5
Dependent Claim
13 words
The method of claim 1 wherein said sample contains a potassium salt additive.
Claim 6
Independent Claim
22 words
The method of claims 1 or 2 wherein said sensor means is initially calibrated prior to placing said sample in the container.
Claim 7
Dependent Claim
47 words
The method of claim 5 including a preliminary step of reading said sensor means prior to placing a sample in the container; and thereafter reading said sensor means without said sample and with a radiation standard source to obtain two measurements for calibration of said sensor means.
Claim 8
Dependent Claim
15 words
The method of claim 1 wherein crushed raw ore is used as said sized sample.
Claim 9
Dependent Claim
15 words
The method of claim 1 wherein processed mud additives are used as said sized sample.
Claim 10
Dependent Claim
64 words
The method of claim 7 including the step of measuring the bulk density of the ore prior to placing the ore in said container wherein the step of coverting includes the following background correction relationship: C.sup.NSC =C.sup.SC -(C.sup.e ×e.sup.-KP) where C e =count rate without sample C SC =count rate with sample C NSC =net count rate K=a constant P=bulk density in weight/cubic measure.
Claim 11
Dependent Claim
62 words
The method of claim 1 including the step of measuring the density of the drilling fluid, and wherein the step of converting includes the following background correction relationship: C.sup.NSCM =C.sup.sc -(C.sup.e ×e.sup.-KB) where C e =count rate without sample C sc =count rate with sample C NSCM =net count rate of mud K=a constant B=drilling mud density in weight per cubic measure.
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) | 1988-01-15 | 1988-07-16 | 1989-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-01-15 | 1992-07-16 | 1993-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-01-15 | 1996-07-16 | 1997-01-15 | $7700.00 | Window Closed / Lapsed |