US4804051A
Expired / Lapsed
US
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Method of predicting and controlling the drilling trajectory in directional wells
Assignee: Baroid Technology Inc
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Filing: 1987-09-25
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Granted: 1989-02-14
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Expires: 2007-09-25
Abstract
Abstract The methods disclosed herein incorporate the basic concepts and methodologies of a new general rock-bit interaction model useful in predicting and controlling drilling trajectories in directional (and deep vertical) wells. It accounts for the anisotropic drilling characteristics of both the formation and the bit. The model is developed in a 3-D geometry. Therefore, it is capable of predicting the walk tendency and the build-drop tendency of a given BHA (bottomhole assembly) under any drilling condition. The model can be used in the forward mode to predict the drilling direction; in the inverse mode to generate the rock and bit anisotrophy indices; and in the log-generation mode to generate drilling logs, such as a drilling dip log.
Inventors
- 👤 Hwa-shan Ho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:06
CPC Classifications
E; E21; E21B; E21B7/00; E21B7/04; E21B44/00; E21B47/00; E21B47/02; E21B47/022
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
81 words
A method for predicting the drilling trajectory of a drill bit in a directional well through an earth formation, comprising the steps of: a. making a first determination of the dip of the said formation; b. making a second determination of the anisotropy index of the said formation; c. making a third determination of the anisotropy index of the said drill bit; and d. combining said first, second and third determinations to produce the instantaneous drilling trajectory of said drill bit.
Claim 2
Independent Claim
81 words
A method for predicting the drilling trajectory of a drill bit in a directional well through an earth formation, comprising the steps of: a. making a first determination of the dip of the said formation; b. making a second determination of the anisotropy index of the said formation; c. making a third determination of the anisotropy index of the said drill bit; and d. combining said first, second and third determinations to produce the instantaneous drilling trajectory of said drill bit.
Claim 3
Dependent Claim
116 words
The method according to claim 1 wherein said combining steps are done in accordance with the relationship r.sub.N *E.sub.r =I.sub.b *I.sub.r *E.sub.f +I.sub.r *(1-I.sub.b)* cos A.sub.af *E.sub.a +(1-I.sub.r)*r.sub.N cos A.sub.rd *E.sub.d, wherein: r N =normalized drilling efficiency under generalized situations; E r =unit vector along drilling direction; I b =bit anisotropy index; I r =rock anisotropy index; E f =unit vector along the resultant bit force on the formation; A bf =angle between the drilling direction and formation normal; E a =unit vector along bit axis direction; A rd =angle between the drilling direction and the formation normal; A af =angle between E a and E f ; E d =unit vector normal to formation bedding.
Claim 4
Dependent Claim
24 words
The method according to claim 1 wherein the steps are carried out repetitively at successive drilling depths to arrive at the predicted drilling trajectory.
Claim 5
Dependent Claim
116 words
The method according to claim 3 wherein said combining steps are done in accordance with the relationship r.sub.N *E.sub.r =I.sub.b *I.sub.r *E.sub.f +I.sub.r *(1-I.sub.b)* cos A.sub.af *E.sub.a +(1-I.sub.r)*r.sub.N cos A.sub.rd *E.sub.d, wherein: r N =normalized drilling efficiency under generalized situations; E r =unit vector along drilling direction; I b =bit anisotroppy index; I r =rock anisotrpy index; E f =unit vector along the resultant bit force on the formation; A bf =angle between the drilling direction and formation normal; E a =unit vector along bit axis direction; A rd =angle between the drilling direction and the formation normal; A af =angle between E a and E f ; E d =unit vector normal to formation bedding.
Claim 6
Independent Claim
83 words
A method for producing the dip of a formation traversed by a well bore resulting from a drill bit drilling through said formation, comprising the steps of: a. making a first determination of the anisotropy index of the said formation; b. making a second determination of the anisotropy index of said drill bit; c. making a third determination of the instantaneous drilling trajectory of said drill bit; and d. combining said first, second and third determinations to produce the dip of said formation.
Claim 7
Independent Claim
83 words
A method for producing the dip of a formation traversed by a well bore resulting from a drill bit drilling through said formation, comprising the steps of: a. making a first determination of the anisotropy index of the said formation; b. making a second determination of the anisotropy index of said drill bit; c. making a third determination of the instantaneous drilling trajectory of said drill bit; and d. combining said first, second and third determinations to produce the dip of said formation.
Claim 8
Dependent Claim
116 words
The method according to claim 5 wherein said combining steps are done in accordance with the relationship r.sub.N *E.sub.r =I.sub.b *I.sub.r *E.sub.f +I.sub.r *(1-I.sub.b)* cos A.sub.af *E.sub.a +(1-I.sub.r)*r.sub.N cos A.sub.rd *E.sub.d, wherein: r N =normalized drilling efficiency under generalized situations; E r =unit vector along drilling direction; I b =bit anisotropy index; I r =rock anisotropy index; E f =unit vector along the resultant bit force on the formation; A bf =angle between the drilling direction and formation normal; E a =unit vector along bit axis direction; A rd =angle between the drilling direction and the formation normal; A af =angle between E a and E f ; E d =unit vector normal to formation bedding.
Claim 9
Dependent Claim
25 words
The method according to claim 5 wherein the steps are carried out repetitively at successive drilling depths to arrive at the dip of the formation.
Claim 10
Dependent Claim
116 words
The method according to claim 7 wherein said combining steps are done in accordance with the relationship r.sub.N *E.sub.r =I.sub.b *I.sub.r *E.sub.f +I.sub.r *(1-I.sub.b)* cos A.sub.af *E.sub.a +(1-I.sub.r)*.sub.r.sub.N cos A.sub.rd *E.sub.d, wherein: r N =normalized drilling efficiency under generalized situations; E r =unit vector along drilling direction; I b =bit anisotropy index; I r =rock anisotropy index; E f =unit vector along the resultant bit force on the formation; A bf =angle between the drilling direction and formation normal; E a =unit vector along bit axis direction; A rd =angle between the drilling direction and the formation normal; A af =angle between E a and E f ; E d =unit vector normal to formation bedding.
Claim 11
Independent Claim
91 words
A method for producing an indication of the anisotropy indices of the drill bit and of the formation traversed by a well bore resulting from a drill bit drilling through said formation, comprising the steps of: a. making a first determination of the dip of the same formation; b. making a second determination of the instantaneous drilling trajectory of said drill bit; and c. combining said first and second determinations to produce indications of the said anisotropy index of the said drill bit and the anisotropy index of the said formation.
Claim 12
Independent Claim
91 words
A method for producing an indication of the anisotropy indices of the drill bit and of the formation traversed by a well bore resulting from a drill bit drilling through said formation, comprising the steps of: a. making a first determination of the dip of the same formation; b. making a second determination of the instantaneous drilling trajectory of said drill bit; and c. combining said first and second determinations to produce indications of the said anisotropy index of the said drill bit and the anisotropy index of the said formation.
Claim 13
Dependent Claim
119 words
The method according to either of claim 9 wherein said combining steps are done in accordance with the relationship r.sub.N *E.sub.r =I.sub.b *I.sub.r *E.sub.f +I.sub.r *(1-I.sub.b)* cos A.sub.af *E.sub.a *E.sub.a +(1-I.sub.r)*r.sub.n cos A.sub.rd *E.sub.d, wherein: r N =normalized drilling efficiency under generalized situations; E r =unit vector along drilling direction; I b =bit anisotropy index; I r =rock anisotropy index; E f =unit vector along the resultant bit force on the formation; A bf =angle between the drilling direction and formation normal; E a =unit vector along bit axis direction; A rd =angle between the drilling direction and the formation normal; A af =angle between E a and E f ; E d =unit vector normal to formation bedding.
Claim 14
Dependent Claim
27 words
The method according to claim 9 wherein the steps are carried out repetitively at successive drilling depths to arrive at the indication of the said anisotropy indices.
Claim 15
Dependent Claim
117 words
The method according to claim 11 wherein said combining steps are done in accordance with the relationship r.sub.N *E.sub.r =I.sub.b *I.sub.r *E.sub.f +I.sub.r *(1-I.sub.b)* cos A.sub.af *E.sub.a +(1-I.sub.r)* r.sub.N cos A.sub.rd *E.sub.d, wherein: r N =normalized drilling efficiency under generalized situations; E r =unit vector along drilling direction; I b =bit anisotropy index; I r =rock anisotropy index; E f =unit vector along the resultant bit force on the formation; A bf =angle between the drilling direction and formation normal; E a =unit vector along bit axis direction; A rd =angle between the drilling direction and the formation normal; A af =angle between E a and E f ; E d =unit vector normal to formation bedding.
Claim 16
Dependent Claim
28 words
The method according to claim 11 characterized further by the step of using the said anisotropy index of the drill bit to generate a drilling bit wear log.
Claim 17
Dependent Claim
26 words
The method according to claim 11 characterized further by the step of using the anisotropy index of the formation to generate a drilling lithology index log.
Claim 18
Independent Claim
98 words
A method for controlling the drilling trajectory of a drill bit included in a drill string having a bottomhole assembly in a directional well through an earth formation, comprising the steps of: a. making a first determination of the dip of the said formation; b. making a second determination of the anisotropy index of the said formation; c. making a third determination of the anisotropy index of the said drill bit; and d. combining said first, second and third determinations to determine the make-up of the bottomhole assembly, to thereby control the drilling trajectory of said drill bit.
Claim 19
Independent Claim
98 words
A method for controlling the drilling trajectory of a drill bit included in a drill string having a bottomhole assembly in a directional well through an earth formation, comprising the steps of: a. making a first determination of the dip of the said formation; b. making a second determination of the anisotropy index of the said formation; c. making a third determination of the anisotropy index of the said drill bit; and d. combining said first, second and third determinations to determine the make-up of the bottomhole assembly, to thereby control the drilling trajectory of said drill bit.
Claim 20
Dependent Claim
116 words
The method according to claim 15 wherein said combination step is done in accordance with the relationship r.sub.N *E.sub.r =I.sub.b *I.sub.r *E.sub.f +I.sub.r *(1-I.sub.b)* cos A.sub.af *E.sub.a +(1-I.sub.r)*r.sub.N cos A.sub.rd *E.sub.d, wherein: r N =normalized drilling efficiency under generalized situations; E r =unit vector along drilling direction; I b =bit anisotropy index; I r =rock anisotropy index; E f =unit vector along the resultant bit force on the formation; A bf =angle between the drilling direction and formation normal; E a =unit vector along bit axis direction; A rd =angle between the drilling direction and the formation normal; A af =angle between E a and E f ; E d =unit vector normal to formation bedding.
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) | 1992-02-14 | 1992-08-15 | 1993-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-14 | 1996-08-15 | 1997-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-14 | 2000-08-15 | 2001-02-14 | $7700.00 | Window Closed / Lapsed |