Patent US4949575A successfully refreshed from Google Patents.
US4949575A
Expired / Lapsed
US
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Formation volumetric evaluation while drilling
Assignee: Anadrill Inc
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Filing: 1989-02-27
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Granted: 1990-08-21
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Expires: 2009-02-27
Abstract
Abstract Formation Strength and other measurement while drilling parameters are combined to produce a formation volumetric analysis which may including the traditional volumetric components of clay volume, sand volume, total porosity, and water filled porosity. In shaley formations, the volumetric analysis may also include an excess or overpressure porosity. Formation Strength may be derived from measurements of torque and weight on bit and be corrected for such effects as bit dullness, mud weight and hydrostatic pressure balance.
Inventors
- 👤 John C. Rasmus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 10:14
CPC Classifications
E; E21; E21B; E21B49/00; E21B49/003; E21B47/00; E21B47/06
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
69 words
A method for investigating properties of subsurface formations traversed by a borehole, the method comprising the steps of: a. deriving a drilling signal indicative of the resistance of the formation to being drilled by a drill bit; b. deriving a plurality of additional signals indicative of formation properties; and b. in response to said drilling signal and to said additional signals, deriving a volumetric analysis of the subsurface formation.
Claim 2
Independent Claim
69 words
A method for investigating properties of subsurface formations traversed by a borehole, the method comprising the steps of: a. deriving a drilling signal indicative of the resistance of the formation to being drilled by a drill bit; b. deriving a plurality of additional signals indicative of formation properties; and b. in response to said drilling signal and to said additional signals, deriving a volumetric analysis of the subsurface formation.
Claim 3
Dependent Claim
26 words
The method as recited in claim 1 wherein said volumetric analysis of the subsurface formation includes a clay volume, a non-clay mineral volume, and a porosity.
Claim 4
Dependent Claim
20 words
The method as recited in claim 1 wherein said additional signals include formation resistivity and formation natural gamma ray radioactivity.
Claim 5
Dependent Claim
14 words
The method as recited in claim 1 wherein said drilling signal includes Formation Strength.
Claim 6
Dependent Claim
20 words
The method as recited in claim 4 wherein said Formation Strength has been corrected for the effects of bit wear.
Claim 7
Dependent Claim
42 words
The method as recited in claim 1 wherein said step of deriving said drilling signal includes the steps of deriving a signal indicative of the weight applied to the bit and of deriving a signal indicative of the torque at the bit.
Claim 8
Dependent Claim
55 words
The method as recited in claim 1 wherein said step of deriving a volumetric analysis includes the step of determining a plurality of tool response equations which each relate a derivable formation property to a plurality of unknown formation properties selected from the group comprising: clay volume, volume of a non-clay mineral, and pore volume.
Claim 9
Dependent Claim
46 words
The method as recited in claim 7 wherin one of said response equations comprises the following relationship: ##EQU7## where FS=measured Formation Strength FS ma =Formation Strength of mineral of volume=1 V cl =clay volume V clzero =clay volume when FS=0 φ ezero =extrapolated porosity where FS=0.
Claim 10
Dependent Claim
26 words
The method as recited in claim 6 wherein said drilling signal is Formation Strength derived from measurements of downhole bit torque and downhole weight on bit.
Claim 11
Dependent Claim
34 words
The method as recited in claim 7 wherein said derivable properties include properties selected from the group comprising Formation Strength, resistivity, natural radioactivity, neutron porosity, gamma ray density, sonic travel-time, and deep induction resistivity.
Claim 12
Dependent Claim
37 words
The method as recited in claim 9 wherein Formation Strength is derived as a function of downhole weight on bit, rate of bit rotation, bit efficiency, gouging component of bit torque, rate of penetration and bit diameter.
Claim 13
Dependent Claim
28 words
The method as recited in claim 7 in which one of the response equations is the Formation Strength response equation which is a function of drilling mud weight.
Claim 14
Dependent Claim
41 words
The method as recited in claim 7 in which one of the response equations is the Formation Strength response equation which is a function of the difference between formation pressure and the drilling fluid pressure at the location of the bit.
References Cited (Backward Citations)
US4064749A
Cited
US4599904A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-08-20 | 1994-02-19 | 1994-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-20 | 1998-02-19 | 1998-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-20 | 2002-02-19 | 2002-08-21 | $7700.00 | Window Closed / Lapsed |