U.S. patent application number 14/125413 was filed with the patent office on 2014-05-15 for two-centre rotary boring bit and method for deepening an existing well.
This patent application is currently assigned to Tercel IP Ltd.. The applicant listed for this patent is Benoit Deschamps, Sebastian Daniel Jean Desmette, Abdelhakim Hahati. Invention is credited to Benoit Deschamps, Sebastian Daniel Jean Desmette, Abdelhakim Hahati.
Application Number | 20140131111 14/125413 |
Document ID | / |
Family ID | 45478608 |
Filed Date | 2014-05-15 |
United States Patent
Application |
20140131111 |
Kind Code |
A1 |
Desmette; Sebastian Daniel Jean ;
et al. |
May 15, 2014 |
TWO-CENTRE ROTARY BORING BIT AND METHOD FOR DEEPENING AN EXISTING
WELL
Abstract
Two-centre rotary boring bit for boring wells, comprising, on
the one hand, a pilot tool (1) comprising a body of revolution with
an axial core (3) and radial blades (4) bearing cutting elements
(5) and, on the other hand, an enlarging tool (2) fitted behind the
pilot tool and laterally offset therefrom, the pilot tool having,
on its front face, a central region (11) that has no cutting
elements in order to allow the creation of a core sample (12), said
central region being in communication with a cavity (13) situated
between two blades (4) of the pilot tool (1) and serving to remove
the core sample toward the periphery of the boring bit.
Inventors: |
Desmette; Sebastian Daniel
Jean; (Thieusies, BE) ; Hahati; Abdelhakim;
(Brussels, BE) ; Deschamps; Benoit; (Gottignie,
BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Desmette; Sebastian Daniel Jean
Hahati; Abdelhakim
Deschamps; Benoit |
Thieusies
Brussels
Gottignie |
|
BE
BE
BE |
|
|
Assignee: |
Tercel IP Ltd.
Tortola
VG
|
Family ID: |
45478608 |
Appl. No.: |
14/125413 |
Filed: |
June 14, 2012 |
PCT Filed: |
June 14, 2012 |
PCT NO: |
PCT/EP2012/002510 |
371 Date: |
January 29, 2014 |
Current U.S.
Class: |
175/57 ;
175/387 |
Current CPC
Class: |
E21B 10/26 20130101 |
Class at
Publication: |
175/57 ;
175/387 |
International
Class: |
E21B 10/26 20060101
E21B010/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 16, 2011 |
BE |
2011/0371 |
Claims
1. Two-centre rotary boring bit for boring wells, comprising, a
pilot tool comprising a body of revolution with an axial core and
radial blades carrying cutting elements and, an enlarging tool
located behind the pilot tool and laterally offset relative to the
pilot tool, wherein the front face of the pilot tool (1) has an
axial central region (11) which is devoid of cutting elements (5)
for allowing the creation of an axial core sample (12), said
central region being in communication with a cavity (13) located
between two blades (4) of the pilot tool and serving to evacuate
the core sample toward the periphery of the boring bit.
2. Boring bit according to claim 1, wherein the cavity (13) is
delimited by two blades (4) of the pilot tool (1) and a clearance
surface (14) set back relative to the front face of said pilot
tool.
3. Boring bit according to claim 1, wherein the enlarging tool (2)
is offset relative to the pilot tool (1), in such a way that a
portion (9) of its peripheral surface is radially set back relative
to the peripheral surface of the pilot tool and in that the cavity
(13) of the pilot tool (1) ends up in said portion (9) of the
peripheral surface of the enlarging tool.
4. Boring bit according to claim 1 wherein the enlarging tool (2)
comprises a core (6) with radial blades (7) carrying cutting
elements (8) and in that the cavity (13) exits between two blades
(7) of the enlarging tool.
5. Boring bit according to claim 1 wherein the blades (4) of the
pilot tool (1) are spiralled.
6. Boring bit according to claim 5, wherein the blades (7) of the
enlarging tools (1) are spiralled and located in the prolongation
of the blades of the pilot tool.
7. Boring bit according to claim 1 wherein the pilot tool (1)
further comprises a device for breaking the core sample (12).
8. Boring bit according to claim 7, wherein the device for breaking
comprises an abrasion-resistant pellet, located in the central
region (11) of the pilot tool (1).
9. Boring bit according to claim 1 wherein the diameter of the
central region (11) of the pilot tool (1) is adjusted so that the
core sample (12) resists the lateral forces generated by the
enlarging tool (2) during use of the boring bit.
10. Boring bit according to claim 1 wherein the diameter of the
central region (11) of the pilot tool (1) is at least equal to the
difference between the overall diameter of the enlarging tool (2)
and the diameter of the pilot tool (1).
11. Boring bit according to claim 1 further comprising channels
(10) for supplying drilling mud, which ends up through the front
face of the pilot tool (1).
12. Boring bit according to claim 11, wherein channels (16) for
supplying drilling mud exit between the blades (7) of the enlarging
tool 2.
13. Boring bit according to claim 1 wherein the cores (3, 6) and
the blades (4, 7) are made of steel and the cutting elements (5, 8)
comprise elements made of PDC.
14. (canceled)
15. Method for deepening existing wells, comprising the step of
implementing a two-centre boring bit in accordance with claim
1.
16. Method according to claim 15, wherein the radius of the central
region (11) of the pilot tool (1) of the boring bit is at least
equal to the difference between the radius of the well (18) and the
radius of the pilot tool (1).
Description
FIELD OF THE INVENTION
[0001] The invention relates to rotary boring bits, especially to
boring bits intended for the boring of wells in deposits of fluids
such as oilfield or gas field.
[0002] The invention relates more particularly to a rotary boring
bit of the two-centre type comprising a pilot tool followed by an
enlarging tool.
PRIOR ART
[0003] Boring bits are boring tools intended to be fixed to the end
of a drill string in order to bore a well to a useful underground
deposit, such as an oilfield, a gas field, water reservoir, ore or
coal deposit. The drill string is supported by a tower located at
the surface. A drilling mud is generally injected inside the drill
string in order to exit via the boring bit and rise back up to the
surface, through the annular space formed between the drill string
and the well in the process of boring. The function of the drilling
mud is to cool the boring bit and to remove the debris from boring
up to the surface.
[0004] Rotary boring bits of the two-centre type are well known in
boring techniques, where they are used for boring wells of large
diameter or for deepening while widening existing wells. These
known boring bits, disclosed in particular in U.S. Pat. No.
5,678,644 and US 2002/0 104 688 comprise a pilot tool, followed by
an enlarging tool, these two tools forming a rigid unitary set. The
pilot tool comprises a body of revolution with an axial core,
carrying at one end, radial and frontal blades provided with
cutting elements and, at the other end, a threaded endfitting for
attaching it to the drill string. The enlarging tool is inserted
between the pilot tool and the threaded endfitting. It comprises a
body provided with cutting elements on only one portion of its
periphery, in such a way that it is asymmetrical, its cutting
elements acting like a milling cutter in order to widen the well in
the process of boring, behind the pilot tool.
[0005] In known two-centre boring bits, described hereinabove, the
effect of the asymmetric profile of the enlarging tool is to
unbalance the boring bits during the boring. This particularity
constitutes a disadvantage of the known two-centre boring bits, by
decreasing the quality and precision. It furthermore subjects the
boring bit to interfering forces, able to damage it
prematurely.
[0006] When these known two-centre boring bits are used to deepen
exiting wells, they are usually therein subjected to an
epicycloidal movement until they exit the tubing. As soon as the
pilot tool of the boring bit exits the tubing, the boring bit
resumes the normal boring of the well, with widening. Under the
effect of the epicycloidal movement, the cutting elements located
in the central portion of the pilot tool are subjected to a
movement of precession and rotate in the opposite direction, which
is detrimental for these cutting elements when they come into
contact with the bottom of the well.
SUMMARY OF THE INVENTION
[0007] The invention aims to overcome the aforementioned
disadvantages of the known boring bits described hereinabove.
[0008] The invention aims more particularly to provide a rotary
boring bit of the two-centre type, of a new design, able to prevent
an unbalancing of the boring bit.
[0009] Another object of the invention consists in providing a
boring bit of the two-centre type having an improved effectiveness
and which allows a higher boring precision.
[0010] An additional object of the invention is to improve the
productivity of the rotary boring bits of the two-centre type, by
making higher boring speeds possible.
[0011] The invention also has for object to increase the precision
of the geological analysis of the rock formation in the process of
boring.
[0012] An additional object of the invention is to provide a
two-centre boring bit which is especially adapted for use in an
existing well for deepening it, especially for use in a well having
a diameter substantially equal to the largest cross-sectional
dimension of the enlarging tool of the boring bit.
[0013] Consequently, the invention relates to a two-centre rotary
boring bit for boring wells, comprising, on the one hand, a pilot
tool comprising a body of revolution with an axial core and radial
blades carrying cutting elements and, on the other hand, an
enlarging tool located behind the pilot tool and laterally offset
relative to the latter; according to the invention, the boring bit
is characterised in that the front face of the pilot tool has an
axial central region which is devoid of cutting elements for
allowing the creation of an axial core sample, said central region
being in communication with a cavity located between two blades of
the pilot tool and allowing evacuation of the core sample toward
the periphery of the boring bit.
DETAILED DESCRIPTION OF THE INVENTION
[0014] In this specification, the terms `front`, `rear`, `in front
of`, `behind`, `anterior` and `posterior` are defined in relation
to the direction of the progression of the boring bit in a well in
the process of boring. Due to this definition, the pilot tool is
located in front of the enlarging tool and the front face of the
pilot tool is the face of the one that is facing the working
face.
[0015] In its general design, the boring bit according to the
invention is of the type of the one described in U.S. Pat. No.
5,678,644.
[0016] The pilot tool comprises a body of revolution provided with
cutting elements. The body of revolution comprises an axial core
the rear portion is arranged in order to be attached to a drill
string coupled to a motor. The attaching of the core to the drill
string is usually carried out by a threaded endfitting arranged on
the rear face of the core.
[0017] A plurality of radial blades are approximately uniformly
distributed along the periphery of the core and they carry the
cutting elements. The material that constitutes the core and blades
is not critical for the definition of the invention. It can be
steel, tungsten carbide or an abrasive material made of impregnated
diamond.
[0018] The cutting elements are not critical for the definition of
the invention and can be all cutting elements commonly used in
rotary boring bits. They can in particular be PDC cutting elements
or infiltrated abrasive elements. PDC (Polycrystalline Diamond
Compact) cutting elements are well known in the mine drilling
sector. They comprise a polycrystalline diamond pellet on a
cemented tungsten carbide substrate and they are usually obtained
by compressing a mixed powder of diamond and cobalt on the tungsten
carbide substrate. Infiltrated abrasive elements are also well
known in mine drilling techniques and are usually obtained by
mixing a powder of diamond (possibly with a powder of metal carbide
added, for example tungsten carbide) with a powder of a meltable
binder (for example a Cu--Mn solder) and by submitting the mixture
created as such to a compacting followed by sintering. Information
on this technique is available in US 2002/0125048A1.
[0019] The enlarging tool is laterally offset relative to the pilot
tool (transversally to the axis of the pilot tool), such that a
portion of its lateral peripheral surface is protruding relative to
the peripheral surface of the pilot tool. The peripheral surface of
the pilot tool is, by definition, the surface of the latter which
is facing the wall of the well in the process of boring. Similarly,
the peripheral surface of the enlarging tool is the surface of the
latter which is facing the wall of the well in the process of
boring. In the boring bit according to the invention, the
aforementioned portion protruding from the peripheral surface of
the enlarging tool is separated from the axis of rotation of the
boring bit by a distance greater than the maximum radius of the
pilot tool (the axis of rotation of the boring bit coinciding with
the axis of symmetry of the pilot tool). Subsequently, the
aforementioned portion of the peripheral surface of the enlarging
tool shall be designated as `widened portion`.
[0020] The enlarging tool is located behind the pilot tool. It
carries, on its aforementioned widened portion, cutting elements.
The material of the enlarging tool, the profile of the enlarging
tool and the cutting elements that are provided on it are not
critical for the definition of the invention. It is generally
preferred that the enlarging tool comprises a core and radial
blades in its widened portion, said blades carrying the cutting
elements. In this particular embodiment of the invention, the core
and the blades can be made of steel, the cutting elements being PDC
cutting elements.
[0021] The enlarging tool and the pilot tool form a stiff composite
assembly, substantially undeformable. These two tools can include a
single tool body, carrying the cutting elements. Alternatively,
they can be formed of the undeformable assembly of two separate
tool bodies (one body for the pilot tool and one body for the
enlarging tool).
[0022] It is preferred, according to the invention, that the core
and the blades of the pilot tool and of the enlarging tool be made
of steel and that their respective cutting elements be PDC cutting
elements. Alternatively, a portion of the PDC cutting elements can
be replaced with abrasive elements made of infiltrated diamonds. In
a modified embodiment, the pilot tool and at least the widened
portion of the enlarging tool can be made of metal-infiltrated
carbide, as it is well known in the technique of oil boring
tools.
[0023] In the boring bit according to the invention, the blades of
the pilot tool extend on the lateral face of the tool body.
[0024] According to a first characteristic of the invention, the
blades of the pilot tool are extended on the front face of the
latter, while still leaving therein an axial central region, devoid
of blades and of cutting elements. This allows the creation of an
axial core sample during the boring.
[0025] According to a second characteristic of the invention, said
axial central region of the pilot tool is in communication with a
cavity located between two blades of the pilot tool. The function
of the cavity is to ensure the evacuation of the core sample toward
the periphery of the boring bit, then in the annular region
delimited behind the boring bit, between the drill string and the
wall of the well in the process of boring. For this purpose, said
cavity is delimited by two lateral surfaces and a clearance surface
located in the back relative to the front face of the tool. These
two lateral surfaces can, advantageously, be two successive blades
of the pilot tool.
[0026] Additional information relating to the two characteristics
of the invention defined hereinabove is available in WO 2008/149240
(TOTAL S.A.).
[0027] It is desirable, according to a particular embodiment of the
invention, that the pilot tool comprise a device for breaking the
core sample. The function of this device for breaking is to break
the core sample at regular intervals in such a way as to obtain
fragments as regular as possible. In this embodiment of the
invention, the device for breaking can for example include an
abrasion-resistant pellet, fitted in the aforementioned cavity of
the pilot tool. This pellet can for example be a PDC cutting
element or a pellet made of an infiltrated abrasive element.
[0028] In the boring bit according to the invention, the core
sample stabilises the boring bit, by exerting a counter reaction to
the lateral forces resulting from the dissymmetry of the enlarging
tool. The core sample as such opposes a lateral deviation of the
pilot tool. The diameter of the aforementioned central region of
the pilot tool conditions the diameter of the core sample. It is to
be calculated for the base of the core sample resists to the
lateral forces generated by the enlarging tool during normal use of
the boring bit and prevents a lateral displacement of the pilot
tool. Selecting this diameter will depend on diverse parameters,
among which are in particular the dimensions of the boring bit, the
type of cutting elements that it is provided with and the
geological nature of the rock in which the well is bored
(non-exhaustive list of examples). It must be determined in each
particular case by those skilled in the art.
[0029] In an advantageous embodiment of the boring bit according to
the invention, a portion of the peripheral surface of the enlarging
tool is radially set back relative to the peripheral surface of the
pilot tool; in this embodiment, the cavity of the pilot tool for
evacuating the core sample ends up at this set back portion of the
enlarging tool. This embodiment facilitates the evacuation of the
debris of the core sample and their transfer behind the boring
bit.
[0030] In another advantageous embodiment of the invention, the
blades of the pilot tool are spiralled. This embodiment of the
invention facilitates the evacuation of debris from the core
sample. In a preferred alternative to this embodiment of the
invention, the enlarging tool comprises blades, which are spiralled
and located in the prolongation of the blades of the pilot tool.
This alternative of the invention improves the evacuation of debris
from the core sample behind the boring bit.
[0031] In an additional embodiment of the invention, the boring bit
further comprises, in a well-known manner in known boring bits,
channels for supplying drilling mud. These channels ends up through
the front face of the pilot tool, between its blades and they
communicate with an axial channel exiting into an internal duct of
the drill string.
[0032] Compared with known two-centre boring bits, the two-centre
boring bit according to the invention has better stability, greater
effectiveness and productivity and greater precision in a boring
operation. The evacuation of debris from the core sample moreover
allows a more precise a mineralogical analysis of the geological
layers that the well passes through.
[0033] The boring bit according to the invention draws a
substantial advantage from the fact that it combines an enlarging
tool and a region for creating a core sample. By allowing the
boring of wells with large diameters, the enlarging tool makes
possible at the same time to create core samples of large diameter,
which has the advantageous consequence of allowing higher boring
speeds and a better geological analysis of the rock.
[0034] The boring bit according to the invention has applications
for the boring of all types of wells for diverse applications. It
is especially suited for boring artesian wells or deep wells in
deposits of coal, ore, oilfield or gas field.
[0035] The boring bit according to the invention has an especially
advantageous application for deepening existing wells and in
particular for boring in plugs of mortar at the bottom of the
latter. In this application of the invention, a boring bit is
selected and is introduced substantially exactly in the existing
well (usually tubed). The overall diameter of the enlarging tool of
the boring bit is substantially equal to the diameter of the well.
In an advantageous embodiment of the invention, especially suited
to this application, the diameter of the aforementioned central
region of the pilot tool is at least equal to the difference
between the overall diameter of the enlarging tool and the diameter
of the pilot tool. The overall diameter of the enlarging tool is,
by definition, its largest cross-section dimension at the axis of
rotation of the pilot tool. When a boring bit according to this
embodiment of the invention is used to deepen an existing well,
none of its cutting elements is submitted to a movement of
precession. In this embodiment of the invention, around said
central region, a sufficient crown of cutting elements needs to be
left for allowing to bore through the bottom of the well.
[0036] The invention then also relates to a method for deepening
existing wells implementing a two-centre boring bit in accordance
with the invention. The invention especially relates to such a
method wherein the radius of the central region of the pilot tool
of the boring bit is at least equal to the difference between the
radius of the well and the radius of the pilot tool.
BRIEF DESCRIPTION OF THE FIGURES
[0037] Particularities and details of the invention shall appear in
the following description of the annexed figures, which show a few
particular embodiments of the invention.
[0038] FIG. 1 is an elevational view of an embodiment of the boring
bit according to the invention;
[0039] FIG. 2 is a front view of the boring bit of FIG. 1;
[0040] FIG. 3 is an elevational view of another embodiment of the
boring bit according to the invention;
[0041] FIG. 4 is a front view of the boring bit of FIG. 3;
[0042] FIG. 5 shows a two-centre boring bit in a well that is being
deepened; and
[0043] FIG. 6 is a front view of a particular embodiment of the
boring bit according to the invention.
[0044] In these figures, the same reference notations designate
identical elements.
DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS
[0045] The boring bit, shown in FIGS. 1 and 2, associates over a
unitary body, a pilot tool 1 and a finishing tool 2.
[0046] The pilot tool 1 is of revolution. It comprises an axial
core 3 made of steel and radial blades 4 made of steel. The radial
blades 4 carry cutting elements 5 at their periphery. The cutting
elements 5 are advantageously PDC cutting elements.
[0047] The enlarging tool 2 comprises a core 6 made of steel,
extending the core 3 of the pilot tool 1. The core 6 carries radial
blades 7 made of steel on a portion of its periphery, with the
remaining portion 9 of its periphery being in the extension of the
core 3 of the pilot tool 1. The radial blades 7 bear cutting
elements 8 made of PDC.
[0048] The blades 7 of the enlarging tool are laterally offset
relative to the pilot tool 1, in such a way that their cutting
elements 8 are protruding in relation to the peripheral surface of
the pilot tool 1. The portion 9 of the enlarging tool 2 is set back
relative to the periphery of the pilot tool 1.
[0049] The core 6 is extended by a threaded endfitting 17 in order
to attach it to the drill string, not shown.
[0050] Channels 10, serving for the supply of drilling mud, exit
through the front face of the pilot tool 1. Similarly, channels 16
for supplying drilling mud exit between the blades (7) of the
enlarging tool 2.
[0051] In accordance with the invention, the blades 4 of the pilot
tool are interrupted in the anterior central region 11 of this
tool. This central region 11 is centred on the axis of the boring
bit (coinciding with the axis of the pilot tool), in such a way
that, during the boring of the well, a cylindrical rock core sample
12 is formed.
[0052] The pilot tool 1 further comprises a cavity 13 for the
evacuation of the core sample 12. This cavity 13 is delimited
between two blades 4 and an inclined clearance surface 14, that
ends up in front of the portion 9 of the core 6 of the enlarging
tool 2.
[0053] In order to dig a well by means of the boring bit of FIGS. 1
and 2, the boring bit is set into rotation in the direction of the
arrow X (FIG. 2) and it is displaced axially in the direction of
the arrow Y (FIG. 1) through a rock formation. As it goes deeper
into the rock, the pilot tool 1 digs the well that the enlarging
tool then widens. The core sample 12 which is formed in the
anterior central region 11 of the pilot tool 1 maintains the boring
bit unit in the axis of the well being dug, despite the lateral
forces generated by the enlarging tool 2. As the boring bit
progresses in the rock formation, the core sample 12 is deviated
laterally over the clearance surface 14 of the cavity 13 wherein it
the core sample gets broken and its debris 15 are evacuated toward
the mouth of the well by the drilling fluid. In an alternative of
the invention, an abrasion-resistant pellet (not shown) is placed
in the cavity 13, for breaking the core sample 12 as it is created.
This pellet can for example be a PDC pellet.
[0054] In the boring bit of FIGS. 3 and 4, the blades 4 of the
pilot tool 1 are spiralled. The radial blades 7 of the enlarging
tool 2 are straight. Alternatively, they could be spiralled in the
same direction as the blades 4 of the pilot tool 1.
[0055] In FIG. 5, an existing well is diagrammatically shown,
wherein a two-centre boring bit has been introduced, for the
purpose of extending said well. The well, shown as an axial
cross-section, is tubed with a metal tube 18. The boring bit is
sized and positioned in such a way that the overall diameter of its
enlarging tool 2 is substantially equal to the diameter of the
well. The boring bit being positioned as such in the well, its axis
19 (axis of symmetry of the pilot tool and of the threaded
endfitting 17) is offset relative to the axis 20 of the well.
During the deepening of the well, the boring bit is submitted to an
epicycloidal movement. According to the invention, the central
region 11 of the pilot tool is delimited by a circle which is
centred on the axis 19 and of which the radius is equal to the
distance separating the two axes 19 and 20. Its radius is
substantially equal to the difference between the radius of the
well 18 and the radius of the pilot tool 1.
[0056] FIG. 6 shows the circular central region 11 of the boring
bit of FIG. 5. This central region 11 is delimited between the axis
19 of the boring bit and the axis 20 of the well 18.
* * * * *