U.S. patent application number 11/395612 was filed with the patent office on 2007-10-04 for drill string system for performing measurement while drilling and logging while drilling operations.
Invention is credited to Calum Robert MacPherson, David F. Sim.
Application Number | 20070227780 11/395612 |
Document ID | / |
Family ID | 38557173 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070227780 |
Kind Code |
A1 |
MacPherson; Calum Robert ;
et al. |
October 4, 2007 |
Drill string system for performing measurement while drilling and
logging while drilling operations
Abstract
A drill string system for performing measurement while drilling
and logging while drilling operations for oil and gas drilling is
provided. The drill string system includes a drill string section
having a bore defined by an inner length of surface of a pipe wall
which has an outer surface. A tool guide is secured in the drill
string section and a support is provided for centering the tool
guide in said bore. Communication ports extend through the drill
pipe wall from the outer pipe surface to the inner surface and
through the support to an inner surface of the tool guide, said
communication ports being in communication with one another. An
elongate cylindrical tool is disposed in the tool guide. A first
terminated passageway in the tool is in communication with a
pressure sensor within the tool to sense the drill string annular
pressure. A second terminated passageway in the tool is in
communication with the drill string bore and in communication with
a pressure sensor within the tool to sense the drill string bore
pressure. A three-dimensional orientation sensor in the tool
determines orientation of the tool. An alignment mechanism is
provided by the tool and the tool guide to inhibit rotation of the
tool relative to the tool guide when the tool is in a desired
orientation relative to the tool guide. The first terminated
passageway is in communication with the communication port of the
tool guide when the tool is in the desired orientation.
Inventors: |
MacPherson; Calum Robert;
(Calgary, CA) ; Sim; David F.; (Calgary,
CA) |
Correspondence
Address: |
BARNES & THORNBURG LLP
P.O. BOX 2786
CHICAGO
IL
60690-2786
US
|
Family ID: |
38557173 |
Appl. No.: |
11/395612 |
Filed: |
March 31, 2006 |
Current U.S.
Class: |
175/320 ;
175/325.5 |
Current CPC
Class: |
E21B 47/022 20130101;
E21B 47/01 20130101; E21B 21/085 20200501; E21B 21/08 20130101;
E21B 47/024 20130101; E21B 47/06 20130101 |
Class at
Publication: |
175/320 ;
175/325.5 |
International
Class: |
E21B 17/00 20060101
E21B017/00 |
Claims
1. A drill string system for performing measurement while drilling
and logging while drilling operations for oil and gas drilling,
said drill string system comprising: a drill string section having
a bore defined by an inner length of surface of a pipe wall which
also has an outer surface; a tool guide secured in said drill
string section and a support for centering said tool guide in said
bore; communication ports extending through said drill pipe wall
from said outer pipe surface to said inner surface and through said
support to an inner surface of said tool guide, said communication
ports being in communication with one another; an elongate
cylindrical tool disposed in said tool guide; a first terminated
passageway in said tool in communication with a pressure sensor
within said tool to sense said drill string annular pressure; a
second terminated passageway in said tool in communication with
said drill string bore and in communication with a pressure sensor
within said tool to sense said drill string bore pressure; a
three-dimensional orientation sensor in said tool determining
orientation of the tool; and an alignment mechanism provided by
said tool and said tool guide for inhibiting rotation of said tool
relative to the tool guide when said tool is in a desired
orientation relative to said tool guide, said first terminated
passageway being in communication with said communication port of
said tool guide when said tool is in said desired orientation.
2. A drill string system of claim 1, wherein said alignment
mechanism comprises an alignment key and a corresponding key
slot.
3. A drill string system of claim 2, wherein said alignment key
comprises at least one biasable element.
4. A drill string system of claim 2, wherein said alignment key
comprises at least one biasable element wherein said alignment key
extends longitudinally along said tool guide.
5. A drill string system of claim 2, wherein said alignment key
comprises at least one biasable element wherein said alignment key
extends longitudinally along said tool guide wherein said alignment
key is tapered at a lower longitudinal end thereof.
6. A drill string system of claim 2, wherein said alignment key
comprises at least one biasable element wherein said key slot
extends longitudinally along said tool and is tapered at a lower
longitudinal end thereof.
7. A drill string system of claim 1, wherein said support comprises
a fit ring connected to said tool guide via support legs extending
longitudinally along said tool guide, said fit ring being fitted to
said inner diameter of said drill string pipe.
8. A drill string system of claim 1, wherein said drill string
system comprises ring seals above and below said communication port
on said tool guide.
9. A drill string system of claim 8, wherein each ring seal is made
of compressible material which permits said tool to slide within
said landing shoe assembly.
10. A drill string system of claim 1, wherein said at least one
seal is provided on said outer surface of said tool.
11. A drill string system of claim 1, wherein said support
comprises at least one leg for spacing said tool guide in said
drill string pipe.
12. A drill string system of claim 11, wherein said support further
comprises a fit ring connected to said at least one leg fitted to
the inner surface of said drill string pipe.
13. A drill string of claim 1, wherein said tool comprises at least
one spacer at a lower end thereof for spacing the tool from the
drill string pipe.
14. A drill string of claim 13, wherein said at least one spacer
comprises at least one fin extending generally radially from said
tool.
15. A drill string of claim 1, wherein said tool comprises a
feature for abutting against said tool guide to limit downward
movement of said tool in said drill string pipe.
16. A drill string of claim 1, further comprising at least one seal
for sealing said communication port in said tool guide and said
first terminated passageway from fluid in said bore.
17. A drill string of claim 1, further comprising at least one seal
for sealing said communication port in said tool guide and said
communication port in said drill pipe wall from fluid in said
bore.
18. A drill string system of claim 1, wherein said tool guide is
tubular.
19. A drill string system for performing measurement while drilling
and logging while drilling operations for oil and gas drilling,
said drill string system comprising: a drill string section having
a bore defined by an inner length of surface of a pipe wall which
also has an outer surface; a tool guide secured in said drill
string section and a support for centering said tool guide in said
bore; communication ports extending through said drill pipe wall
from said outer pipe surface to said inner surface and through said
support to an inner surface of said tool guide, said communication
ports being in communication with one another; an elongate
cylindrical tool disposed in said tool guide; a first pressure
sensor within said tool to sense said drill string annular
pressure; a second pressure sensor in said tool in communication
with said drill string bore to sense said drill string bore
pressure; a three-dimensional orientation sensor in said tool
determining orientation of the tool; and a mechanical retention
device connected to said tool guide for inhibiting rotation of said
tool relative to the tool guide when said tool is in a desired
orientation relative to said tool guide, said first terminated
passageway being in communication with said communication port of
said tool guide when said tool is in said desired orientation.
20. A landing assembly for use in a drill string section, said
landing sleeve assembly comprising: a tool guide for receiving an
elongate cylindrical tool; a support for centering said tool guide
in a bore of said drill string section; a communication port
extending through said tool guide and said support for
communication with a corresponding communication port in said drill
string section and a pressure sensor in said tool when said landing
assembly is placed in said drill string section; and a mechanical
retention device connected to said tool guide and said support for
inhibiting rotation of said tool relative to the tool guide when
said tool is in a desired orientation relative to said tool guide.
Description
FIELD OF THE INVENTION
[0001] The invention relates generally to the field of drilling
and, more particularly, to the field of"underbalanced" drilling
systems.
BACKGROUND OF THE INVENTION
[0002] Petroleum exploration activities occasionally require
specialized drilling techniques to optimise production from certain
types of reservoir stratum. One such drilling technique is known as
"underbalanced" drilling, which employs singly or a combination of
nitrogen, carbon dioxide or other inert gasses, and drilling mud as
the primary composite drilling fluid. In this situation, downhole
pressure of the composite drilling fluid is monitored within the
drill string bore and the well annulus, with the goal of preventing
formation fracture due to overly high gas pressures. Another goal
of underbalanced drilling is to minimise loss of the composite
drilling fluid to the formation, which can be re-circulated until
drilling is complete. As with all directional drilling, the
orientation of the drill string is monitored to determine the
actual drilling path to permit correction where the actual drilling
path has deviated from the desired drilling path.
[0003] Such systems generally employ a tool disposed in the bore of
the drill string that is operable to both determine the pressure
inside and outside and the orientation of the drill string. The
tool includes a three-dimensional orientation sensor for
determining the orientation of the tool. As it is ultimately
desired to determine the orientation of the drill string, the tool
is secured in a fixed known position inside the drill string. The
orientation of the drill string can thereafter be determined using
the orientation information reported by the tool to the surface. In
current systems, the orientation of the tool relative to the drill
string is maintained by retaining the tool in a tool guide at its
upper end and seating the tool in a mule shoe at its lower end. The
tool guide permits rotation and vertical travel of the tool. The
mule shoe has a helical groove into which the tool is fitted in
order to limit vertical travel of the tool and to maintain the tool
in a known orientation relative to the drill string. Deployment of
the muleshoe, however, is time-consuming and costly.
SUMMARY OF THE INVENTION
[0004] In accordance with an aspect of the invention, there is
provided a drill string system for performing measurement while
drilling and logging while drilling operations for oil and gas
drilling, said drill string system comprising:
[0005] a drill string section having a bore defined by an inner
length of surface of a pipe wall which also has an outer
surface;
[0006] a tool guide secured in said drill string section and a
support for centering said tool guide in said bore;
[0007] communication ports extending through said drill pipe wall
from said outer pipe surface to said inner surface and through said
support to an inner surface of said tool guide, said communication
ports being in communication with one another;
[0008] an elongate cylindrical tool disposed in said tool
guide;
[0009] a first terminated passageway in said tool in communication
with a pressure sensor within said tool to sense said drill string
annular pressure;
[0010] a second terminated passageway in said tool in communication
with said drill string bore and in communication with a pressure
sensor within said tool to sense said drill string bore
pressure;
[0011] a three-dimensional orientation sensor in said tool
determining orientation of the tool; and
[0012] an alignment mechanism provided by said tool and said tool
guide for inhibiting rotation of said tool relative to the tool
guide when said tool is in a desired orientation relative to said
tool guide, said first terminated passageway being in communication
with said communication port of said tool guide when said tool is
in said desired orientation.
[0013] The alignment mechanism can be an alignment key and a
corresponding key slot. The alignment key and key slot can extend
longitudinally along the tool guide and the tool. The alignment key
can be at least one biasable element and the alignment key can be
tapered at a lower longitudinal end thereof. The key slot can also
be tapered at a lower longitudinal end thereof. The support can be
a fit ring connected to the tool guide via support legs extending
longitudinally along the tool guide, the fit ring being fitted to
the inner diameter of the drill string pipe. The drill string
system can include ring seals above and below the communication
port on the tool guide.
[0014] The tool can comprise at least one spacer at a lower end
thereof for spacing the tool from the drill string pipe. The at
least one spacer can be centralizer fins that extend generally
radially from the tool. The tool can include a feature to abut
against the tool guide to limit vertical movement of the tool in
the drill string pipe. The tool guide can be tubular.
[0015] In accordance with another aspect of the invention, there is
provided a drill string system for performing measurement while
drilling and logging while drilling operations for oil and gas
drilling, said drill string system comprising:
[0016] a drill string section having a bore defined by an inner
length of surface of a pipe wall which also has an outer
surface;
[0017] a tool guide secured in said drill string section and a
support for centering said tool guide in said bore;
[0018] communication ports extending through said drill pipe wall
from said outer pipe surface to said inner surface and through said
support to an inner surface of said tool guide, said communication
ports being in communication with one another;
[0019] an elongate cylindrical tool disposed in said tool
guide;
[0020] a first pressure sensor within said tool to sense said drill
string annular pressure;
[0021] a second pressure sensor in said tool in communication with
said drill string bore to sense said drill string bore
pressure;
[0022] a three-dimensional orientation sensor in said tool
determining orientation of the tool; and
[0023] a mechanical retention device connected to said tool guide
for inhibiting rotation of said tool relative to the tool guide
when said tool is in a desired orientation relative to said tool
guide, said first terminated passageway being in communication with
said communication port of said tool guide when said tool is in
said desired orientation.
[0024] In accordance with a further aspect of the invention, there
is provided a landing assembly for use in a drill string section,
said landing sleeve assembly comprising:
[0025] a tool guide for receiving an elongate cylindrical tool;
[0026] a support for centering said tool guide in a bore of said
drill string section;
[0027] a communication port extending through said tool guide and
said support for communication with a corresponding communication
port in said drill string section and a pressure sensor in said
tool when said landing assembly is placed in said drill string
section; and
[0028] a mechanical retention device connected to said tool guide
and said support for inhibiting rotation of said tool relative to
the tool guide when said tool is in a desired orientation relative
to said tool guide.
[0029] The drill string system and landing assembly of the
invention facilitates and/or maintains correct rotational alignment
of a pressure measurement and orientation tool within a drill
string bore.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] A preferred embodiment of the invention is described with
respect to the drawings wherein:
[0031] FIG. 1 is a schematic diagram of a downhole drill
string;
[0032] FIG. 2a is a sectional view of the lower end of the drill
string;
[0033] FIG. 2b is a schematic diagram of the geometry of the drill
string;
[0034] FIG. 3 is a sectional view of a drill string system of this
invention;
[0035] FIG. 4 is an exploded sectional view of the drill string
system of FIG. 3;
[0036] FIG. 5 is another exploded view of the drill string system
of FIG. 3; and
[0037] FIG. 6 is a sectional view of a drill string section with a
landing shoe assembly placed therein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] A representative drilling system is shown in FIGS. 1 and 2a.
The above ground drilling structure 10 has the usual tower 11 with
drill string assembly and drive components 12. The drill string 13
is made up of individual drill string sections 14. The lowest drill
string section is coupled to a collar 15, a bent subassembly 16,
and a mud motor in unit 17 for driving a drill bit 18. The drilling
structure 10 operates in a bore 19 in the earth formation created
by the downward movement of the drill bit 18. The space around the
drill string 13 within the bore 19 is referred to as an annular
space 20. The drilling structure is capable of performing
directional drilling via the drill bit 18 that is angled via the
bent subassembly 16.
[0039] FIG. 2b illustrates various axes corresponding to the
orientation of the drill string system. The vector representing the
axis of the lower end of the drill string 13 is identified as
A.sub.DS. The vector representing the axis of the drill bit is
identified as A.sub.DB. The vector A.sub.DB has a component that is
coaxial to A.sub.DS, namely A.sub.DB.sup.C, and a component that is
normal to A.sub.DS, namely A.sub.DB.sup.N. A vector, V.sub.HS, is
defined as being the polar opposite of A.sub.DB.sup.N. This vector
represents the "highside" of the drill string 13 as indicated on
FIG. 2a. In order to cause the drill bit 18 to "steer" away from
the highside direction, downward pressure is applied to the drill
string 13, causing the drill bit 18 to deviate direction.
[0040] In order to clear away materials from the drill bore 19, a
drilling fluid is pumped downwards through a bore in the drill
string 13. The drilling fluid exits the drill string 13 adjacent
the drill bit 18 and flows upwards within the annular space 20
about the periphery of the drill string 13. Differences between the
drill string bore pressure and drill string annular pressure can
result in fractures in the drill string 13. In order to monitor
these pressures, the drill string 13 is provided with electronic
components that are used to provide for "measurement while drilling
and logging while drilling operations".
[0041] A drill string system 24 in accordance with an embodiment of
the invention shown in FIG. 3. The system 24 enables alignment of
the electronic components in a fixed orientation within a
specialized downhole drill string segment referred to as a landing
sleeve 28. An upper female connector 32 of the landing sleeve 28 is
connected to a male threaded connector of an upper drill string
section. Correspondingly, a lower male connector 36 of the landing
sleeve 28 is threaded into the collar 15. The electronic components
for measurement while drilling, logging while drilling and the
determination of orientation are housed in an elongate cylindrical
tool 40. The tool 40 is positioned within a landing shoe assembly
44 that is fitted within the landing sleeve 28. A tapered sleeve
insert 48 is disposed above the landing shoe assembly 44 in the
landing sleeve 28 and a seal ring 52 is placed atop the tapered
sleeve insert 48. Centralizer fins 56 project generally radially
from a lower end 60 of the tool 40 to fix the lower end 60 of the
tool 40 in a coaxial relation within the landing sleeve 28. The
centralizer fins 56 permit flow of drill fluid thereby. A toothed
crown 64 is secured to an upper end of the tool 40 and allows a
rotational force to be applied to the tool 40 in order to rotate it
when it is disposed within the landing sleeve 28.
[0042] The cylindrical tool 40 contains a multitude of electrical
opponents therein, including devices for measuring drilling fluid
pressure in a bore 68 of the drill string and the drill string
annular pressure in the annular space 20. The annular space 20 is
defined between earth formations and an exterior 76 of the landing
sleeve 28. A pressure transducer 80 is provided to measure the
pressure of a circulating drilling fluid in the drill string bore
68. A port 104 in the tool 40 communicates with a passageway 108,
and terminates at the pressure transducer 80. The pressure in the
annular space 20 surrounding the drill string is measured by a
pressure transducer 92. The pressure transducer 92 is in
communication with a passageway 96 which, in turn, communicates
through a port 100. In turn, port 100 is in communication with a
port 104 through the landing shoe assembly 44 and ultimately with a
passageway 108 in the landing sleeve 28. The external entrance of
the port 104 is located within a recessed region 106 on the
periphery of the landing shoe assembly 44. The passageway 108 has a
removable plug 112 inserted therein that fits into the recessed
region 106 of the landing shoe assembly 44 to fix movement of the
landing shoe assembly 44 relative to the landing sleeve 28. The
removable plug 112 has a port 116 that communicates with the
annular space 20, noted as the drill string annular space 20 that
conveys returned drilling fluid to the surface. As a result, the
pressurized fluid in the annular space 20 outside of the landing
sleeve 28 can communicate static pressure through ports 116, 104
and 100 and through passageway 96 to the pressure transducer
92.
[0043] Port 104 is located on a side of the tool 40 opposite port
100 and is in communication with the pressurized fluid within the
bore of the drill string. Port 100 is located between seals
generally designated as 120 and 124. The cylindrical tool 40 is of
a dimension that readily slides through the bore of landing shoe
assembly 44. Seals 120 and 124 project slightly from the periphery
of the tool and form an interference fit with the interior surface
128 of the landing shoe assembly 44, the resulting seal deformation
providing a liquid tight seal with the interior of the landing shoe
assembly 44. As a result, the seals 120 and 124 prevent the fluid
from the drill string bore 68, which is at a higher pressure than
the fluid in the annular space 20, from leaking into the annular
space formed between the seals 120 and 124, the tool 40 and landing
shoe assembly 44.
[0044] A third seal 132 similar to seals 120, 124 is provided to
stabilize lateral movement of the tool 40 within the landing shoe
assembly 44. Although, in accordance with this embodiment, the
seals are provided in the tool 40, it is appreciated that the seals
may be provided on the inner surface 128 of the landing shoe
assembly 44 to provide a sealed space when the tool 40 is inserted
into the landing shoe assembly 44.
[0045] The landing shoe assembly 44 includes an outer fit ring 136
attached to an upper end of a tool guide 140 by three legs 144. The
tool guide 140 can be any shape that permits axial and rotational
movement of the tool 40 while retaining the tool coaxially relative
to the landing sleeve 28. The outer fit ring 136 and the tool guide
140 are coaxially aligned. The legs 144 radially extend from the
tool guide 140 to the outer fit ring 136 to space the outer
periphery of the tool guide 140 from the interior surface of the
landing sleeve 28. Three arcuate channels 152 are defined by the
legs 144 between the outer fit ring 136 and the tool guide 140. The
arcuate channels 152 allow the pressurized drilling fluid in the
drill string bore 68 to flow through the spaces defined between the
periphery of the tool guide 140 and the interior of the landing
sleeve 28. Seals 156, 160 are seal rings that project slightly from
the outer periphery of landing shoe assembly. Seals 156, 160 are
seal rings that project slightly from the outer periphery of the
landing shoe assembly 44.
[0046] The tool 40 also includes a three-dimensional orientation
sensor 162 for determining its orientation. Various types of
three-dimensional orientation sensor known to those skilled in the
art can be employed. In the described embodiment, the
three-dimensional orientation sensor is a three-dimensional
compass.
[0047] In order to determine the direction of the drilling being
performed, the orientation of the lower end of the drill string is
used to gauge along what path the drilling is headed. In
particular, the orientation of the landing sleeve 28 is used. As
the orientation of the tool 40 can be determined, the tool 40 is
fixed in a known orientation inside the landing sleeve 28. This is
achieved primarily by an alignment mechanism provided by the tool
40 and the tool guide 140.
[0048] The electrical components of the tool 40 communicate the
drill string bore and annulus pressures and orientation to the
surface via telemetry, such as Mud Pulse Telemetry or
Electro-Magnetic Telemetry.
[0049] The alignment mechanism includes an alignment key 164
located on a lower end of the tool guide 140. The alignment key 164
is slip-fitted into a vertically-extending machined aperture 168 in
an extension of one of legs 144 along the lower end of the tool
guide 140. A pair of bolts 170 secures the alignment key 164 to the
tool guide 140. The alignment key 164 includes alignment elements
172 that are spring-biased towards the axis of the tool guide 140.
The alignment elements 172 form a projection 176 that is tapered at
its longitudinal ends.
[0050] In addition, the alignment mechanism includes a vertical key
slot 180 machined into the outer surface of the tool 40 directly
below and radially aligned with the port 100. The key slot 180 has
dimensions that are complementary to the projection 176 of the
alignment key 164. In particular, the key slot 180 has a tapered
upper end 184, that transitions to a flat recess 188 and a tapered
lower end 192, providing a valley-like vertical profile. Lateral
sides 196, 200 of the key slot 180 are not tapered.
[0051] A shoulder 204 of the tool above seal 120 is set in a
machined annular recess 208 on the inner surface 128 of the tool
guide 44.
[0052] The exterior passageway 108 extends through the wall of the
landing sleeve 28. The passageway 108 communicates with the port
104 which extends through the leg 144 of the landing shoe assembly
44 via a space defined between the exterior surface of the inner
surface 148 of the landing sleeve 28 and the outer surface of the
outer fit ring 136 of the landing shoe assembly 44. There is a
slight gap between the inner surface 148 of the landing sleeve 28
and the outer surface of the landing shoe assembly 44 to permit
insertion of the landing shoe assembly 44 in the landing sleeve 28.
This space is sealed off to each side of the port 100 by seals 156
and 160, which form a liquid tight seal with the inner surface 148
of the landing sleeve 28 to inhibit fluid from the bore 68 of the
landing sleeve 28 from entering port 104 or passageway 108. This
ensures that all pressurized fluids passing through passageway 108
and port 104 are contained within the annular space. The port 104
opens up into the space defined between the exterior surface of the
cylindrical tool 40 and the inner surface 128 of the landing shoe
assembly 44. There is a slight gap between the cylindrical tool 40
and the inner surface 128 of the landing shoe assembly 44 to permit
insertion and retraction of the cylindrical tool 40. This space is
sealed off to each side of the port 104 by seals 120 and 124. This
ensures that all pressurized fluids passing through passageway 108
and port 104 are contained within the annular space. Port 100 is in
communication with the annular space so that any pressurized fluid
in the annular space enters port 100 and travels along passage 96.
As a result, the pressure of such fluid is sensed by the pressure
transducer 92.
[0053] When the drilling system 24 is being assembled at the
surface, the landing shoe assembly 44 is fitted into the landing
sleeve 28. The recessed region 106 is aligned with the passageway
108 and the plug 112 is inserted into the passageway 108. When
fully inserted, the plug 112 projects into the recessed region 106
which is dimensioned to inhibit movement of the landing sleeve
assembly 44 when the plug 112 is inserted. The tapered sleeve
insert 48 is inserted into the landing sleeve 28 after insertion of
the landing shoe assembly 44, and the seal ring 52 is placed atop
the tapered sleeve insert 48. The tool 40 is then inserted into the
bore of the landing sleeve 28 through the landing shoe assembly 44
until the shoulder 204 of the tool 40 abuts against the machined
annular recess 208 of the landing shoe assembly 44. The shape of
the tapered sleeve insert 48 guides insertion of the cylindrical
tool 40 into the landing shoe assembly 44 during assembly.
[0054] The tapered sleeve insert 48 and seal ring 52 are retained
in place by connection of a drill string section to landing sleeve
28. The seal ring 52 is compressed between the tapered sleeve
insert 48 and the end of the male connector 36 of the connecting
drill string section, thereby creating a liquid tight seal between
the bore of the landing sleeve 28 and that of the connecting drill
string section. An apertured bracket is secured over the toothed
crown and limits upward movement of the tool 40.
[0055] In order to fix the orientation of the tool 40 within the
landing sleeve 28, the tool 40 is rotated via a rotary drive
coupled to the toothed crown 64 until the alignment key 164 is
radially aligned with the key slot 180 of the tool 40. In this
position, the projection 176 then moves freely into the key slot
180. Upon biasing of the projection 176 of the alignment key 164
into the key slot 180, abutment of the projection 176 with the side
walls 196, 200 inhibits further rotation of the tool 40 in either
direction. As the tool guide 140 and the centralizer fins 56
maintain the upper and lower ends of the tool 40 coaxial to the
landing sleeve 28, and the alignment mechanism inhibits rotation of
the tool 40, the tool 40 is held in a fixed known orientation
relative to the landing sleeve 28. Thus, the orientation of the
landing sleeve 28 can be determined from the orientation of the
tool 40.
[0056] Thereafter, further sections of the drill string 13 are
appended atop the landing sleeve 28 to construct the drill string
13.
[0057] In this manner a reliable economical system is provided
which permits securement of a tool having a three-dimensional
orientation sensor inside the drill string in a fixed known
orientation relative thereto.
[0058] Although preferred embodiments of the invention have been
described herein in detail, it will be understood by those skilled
in the art that variations may be made thereto without departing
from the spirit of the invention or the scope of the appended
claims.
* * * * *