US5222048A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for determining borehole fluid influx
Assignee: Baker Hughes Oilfield Operations LLC
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Filing: 1990-11-08
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Granted: 1993-06-22
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Expires: 2010-11-08
Abstract
Abstract Fluid influx in a borehole is determined by examining and monitoring the computed transfer function in the signal channel defined by the annulus between the borehole and a drillstring in the borehole.
Inventors
- 👤 Donald S. Grosso
- 👤 Ali H. Abdallah
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:26
CPC Classifications
E; E21; E21B; E21B47/00; E21B47/10; E21B47/107; E21B47/12; E21B47/14; E21B47/18; G; G01; G01H; G01H17/00; H; H04; H04L; H04L7/00; H04L7/04; H04L7/041
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
108 words
A method of detecting fluid influx in an annulus defined between a drill string and a borehole, the drill string and borehole having drilling fluid therein, comprising the steps of: transmitting an input signal through the annulus from a downhole location to define a transmitted signal; detecting the transmitted signal uphole of the downhole location to determine an annulus output signal; determining the transfer function over a range of frequencies in a frequency domain of the annulus based on the input and output signals; monitoring said transfer function for detecting changes in said transfer function with respect to time so as to determine fluid influx in the annulus.
Claim 2
Independent Claim
108 words
A method of detecting fluid influx in an annulus defined between a drill string and a borehole, the drill string and borehole having drilling fluid therein, comprising the steps of: transmitting an input signal through the annulus from a downhole location to define a transmitted signal; detecting the transmitted signal uphole of the downhole location to determine an annulus output signal; determining the transfer function over a range of frequencies in a frequency domain of the annulus based on the input and output signals; monitoring said transfer function for detecting changes in said transfer function with respect to time so as to determine fluid influx in the annulus.
Claim 3
Dependent Claim
17 words
The method of claim 1 wherein: said input signal is transmitted as a known pre-determined input signal.
Claim 4
Dependent Claim
24 words
The method of claim 1 including the step of: reconstructing the input signal transmitted from downhole based on analysis of the annulus output signal.
Claim 5
Dependent Claim
76 words
The method of claim 1 wherein said drill string has an interior having drilling fluid therein and wherein said input signal is also transmitted through the interior of the drill string and including: detecting the transmitted signal transmitted through the interior of the drill string uphole of the downhole location to determine a drill string output signal; and reconstructing the input signal transmitted from the downhole location based on analysis of the drill string output signal.
Claim 6
Dependent Claim
17 words
The method of claim 1 including: monitoring said transfer function to determine changes in phase and amplitude.
Claim 7
Dependent Claim
29 words
The method of claim 1 including: monitoring the annulus transfer function with respect to time and determining fluid influx in the annulus by changes in said annulus transfer function.
Claim 8
Dependent Claim
36 words
The method of claim 1 including: monitoring the annulus transfer function with respect to time as compared to a reference transfer function and determining fluid influx in the annulus by changes in said annulus transfer function.
Claim 9
Dependent Claim
49 words
The method of claim 1 wherein said step of determining the transfer function comprises the steps of: taking the Discrete Fourier Transform of the transmitted signal and the annulus output signal; and determining the auto and cross power spectral densities of the transmitted signal and the annulus output signal.
Claim 10
Dependent Claim
14 words
The method of claim 1 wherein: said transmitted signal is detected near the surface.
Claim 11
Dependent Claim
14 words
The method of claim 1 wherein: said transmitted signal is detected at the surface.
Claim 12
Dependent Claim
15 words
The method of claim 1 including: monitoring said transfer function to determine changes in phase.
Claim 13
Dependent Claim
21 words
The method of claim 4 wherein: the signal transmitted through the interior of the drill string is detected at the surface.
Claim 14
Dependent Claim
21 words
The method of claim 4 wherein: the signal transmitted through the interior of the drill string is detected near the surface.
Claim 15
Dependent Claim
15 words
The method of claim 1 including: monitoring said transfer function to determine changes in amplitude.
References Cited (Backward Citations)
GB2049934A
Cited
US5055837A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-21 | 1996-12-21 | 1997-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-21 | 2000-12-21 | 2001-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-21 | 2004-12-21 | 2005-06-22 | $7700.00 | Window Closed / Lapsed |