Patent US3785446A successfully refreshed from Google Patents.
US3785446A
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US
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Predicting occurrence of geopressured subterranean zones during drilling
Assignee: ConocoPhillips Co
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Filing: 1971-08-20
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Granted: 1974-01-15
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Expires: 1991-08-20
Abstract
Abstract An early warning detection method for predicting abnormal formation pressure in subterranean rock strata before it is drilled. The technique is to measure, on a sample removed from the well bore an electrical characteristic such as the resistivity or its reciprocal, conductivity, preferably corrected for formation temperature, while the well is being drilled, in the normally pressured rock strata existing above the abnormally pressured formations. When variations are observed in the degree of change of resistivity or conductivity with depth, drilling procedures are altered to meet the requirements of the formation which is about to be penetrated by the drill bit.
Inventors
- 👤 W Fertl
- 👤 R Cavanaugh
- 👤 J Hillhouse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:03
CPC Classifications
E; E21; E21B; E21B47/00; E21B47/06; E21B21/00; E21B21/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
102 words
A method for detecting the approach of an underlying abnormally pressured zone while drilling normally pressured zones of a subterranean strata comprising: a. drilling the normally pressured zones with a drilling fluid whose pressure is balanced against the subterranean strata pressure, b. determining an electrical characteristic of a sample of the subterranean strata being drilled, c. when the rate of change of such electrical characteristic with depth begins to change greatly, instituting controlled drilling procedures, and thereafter d. when the abnormally pressured zone is penetrated, adjusting the drilling fluid pressure to balance the same against the pressure in the abnormally pressured zone.
Claim 2
Independent Claim
102 words
A method for detecting the approach of an underlying abnormally pressured zone while drilling normally pressured zones of a subterranean strata comprising: a. drilling the normally pressured zones with a drilling fluid whose pressure is balanced against the subterranean strata pressure, b. determining an electrical characteristic of a sample of the subterranean strata being drilled, c. when the rate of change of such electrical characteristic with depth begins to change greatly, instituting controlled drilling procedures, and thereafter d. when the abnormally pressured zone is penetrated, adjusting the drilling fluid pressure to balance the same against the pressure in the abnormally pressured zone.
Claim 3
Dependent Claim
11 words
The method of claim 1 wherein the electrical characteristic is resistivity.
Claim 4
Dependent Claim
11 words
The method of claim 1 wherein the electrical characteristic is conductivity.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein the controlled drilling procedures instituted comprise keeping a constant rotary speed and weight on the bit while monitoring the penetration rate.
Claim 6
Dependent Claim
21 words
The method of claim 2 wherein the resistivity is corrected for the temperature of the formation whose resistivity is being measured.
Claim 7
Independent Claim
99 words
A method for detecting the approach of an underlying geopressure zone while drilling normally pressured subterranean strata comprising: a. drilling the normally pressured subterranean strata with a drilling fluid whose pressure against the subterranean strata is balanced againsT pressure in the subterranean strata, b. determining the resistivity of a sample of the subterranean strata being drilled, c. when the resistivity begins to decrease substantially instituting controlled drilling procedures, and d. when the controlled drilling procedures indicate that a geopressured zone has been penetrated, adjusting the drilling fluid pressure to balance the same against the pressure in the geopressured zone.
Claim 8
Independent Claim
99 words
A method for detecting the approach of an underlying geopressure zone while drilling normally pressured subterranean strata comprising: a. drilling the normally pressured subterranean strata with a drilling fluid whose pressure against the subterranean strata is balanced againsT pressure in the subterranean strata, b. determining the resistivity of a sample of the subterranean strata being drilled, c. when the resistivity begins to decrease substantially instituting controlled drilling procedures, and d. when the controlled drilling procedures indicate that a geopressured zone has been penetrated, adjusting the drilling fluid pressure to balance the same against the pressure in the geopressured zone.
Claim 9
Dependent Claim
21 words
The method of claim 6 wherein the resistivity is corrected for the temperature of the formation whose resistivity is being measured.
Claim 10
Independent Claim
99 words
A method for detecting the approach of an underlying geopressure zone while drilling normally pressured subterranean strata comprising: a. drilling the normally pressured subterranean strata with a drilling fluid whose pressure against the subterranean strata is balanced against pressure in the subterranean strata, b. determining the conductivity of a sample of the subterranean strata being drilled, c. when the conductivity begins to increase substantially instituting controlled drilling procedures, and d. when the controlled drilling procedures indicate that a geopressured zone has been penetrated, adjusting the drilling fluid pressure to balance the same against the pressure in the geopressured zone.
Claim 11
Independent Claim
99 words
A method for detecting the approach of an underlying geopressure zone while drilling normally pressured subterranean strata comprising: a. drilling the normally pressured subterranean strata with a drilling fluid whose pressure against the subterranean strata is balanced against pressure in the subterranean strata, b. determining the conductivity of a sample of the subterranean strata being drilled, c. when the conductivity begins to increase substantially instituting controlled drilling procedures, and d. when the controlled drilling procedures indicate that a geopressured zone has been penetrated, adjusting the drilling fluid pressure to balance the same against the pressure in the geopressured zone.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |