US3722606A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detecting abnormal formation pressure during drilling of a well
Assignee: ConocoPhillips Co
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Filing: 1971-08-16
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Granted: 1973-03-27
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Expires: 1991-08-16
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, the tendency of an atomic particle to escape from the environment, such as the pH or redox potential, while the well is being drilled, in the normally pressured rock strata existing above the abnormally pressured formations. When variations are observed in the rate of change of escape tendency 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
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:31
CPC Classifications
E; E21; E21B; E21B49/00; E21B49/005; E21B21/00; E21B21/08
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
111 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. monitoring the tendency of an atomic particle to escape from a sample of the subterranean strata being drilled, c. when the rate of change of tendency of such an atomic particle to escape with depth begins to change greatly, instituting controlled drilling procedures, and 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
111 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. monitoring the tendency of an atomic particle to escape from a sample of the subterranean strata being drilled, c. when the rate of change of tendency of such an atomic particle to escape with depth begins to change greatly, instituting controlled drilling procedures, and 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
27 words
The method of claim 1 wherein the tendency of an atomic particle to escape is measured by determining the pH of a sample of said subterranean strata.
Claim 4
Dependent Claim
28 words
The method of claim 1 wherein the tendency of an atomic particle to escape is measured by determining the redox potential of a sample of said subterranean strata.
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
Independent Claim
111 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. monitoring the tendency of an atomic particle to escape from a sample of the subterranean strata being drilled, c. when the tendency of such an atomic particle to escape begins to decrease, 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 7
Independent Claim
111 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. monitoring the tendency of an atomic particle to escape from a sample of the subterranean strata being drilled, c. when the tendency of such an atomic particle to escape begins to decrease, 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
Dependent Claim
28 words
The method of claim 5 wherein the tendency of an atomic particle to escape is measured by determining the redox potential of a sample of said subterranean strata.
Claim 9
Dependent Claim
27 words
The method of claim 5 wherein the tendency of an atomic particle to escape is measured by determining the pH of a sample of said subterranean strata.
Claim 10
Dependent Claim
27 words
The method of claim 6 wherein the controlled drilling procedures instituted comprise keeping a constant rotary speed and weight on the bit while monitoring the penetration rate.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |