U.S. patent application number 14/127584 was filed with the patent office on 2014-04-17 for tubular device with radiofrequency communication for well head.
This patent application is currently assigned to VAM DRILLING FRANCE. The applicant listed for this patent is Alexandre Fraignac, Yannick Mfoulou. Invention is credited to Alexandre Fraignac, Yannick Mfoulou.
Application Number | 20140104073 14/127584 |
Document ID | / |
Family ID | 47423020 |
Filed Date | 2014-04-17 |
United States Patent
Application |
20140104073 |
Kind Code |
A1 |
Fraignac; Alexandre ; et
al. |
April 17, 2014 |
TUBULAR DEVICE WITH RADIOFREQUENCY COMMUNICATION FOR WELL HEAD
Abstract
An element for a drill string including a body with a generally
axisymmetric appearance and a wave type communication device
installed in the body. The communication device includes a set of
antennae including plural antennae distributed at a periphery of
the body, about an axis of symmetry thereof, and capable of
operating in transmission and in reception, operating electronics
capable of organizing transfer of data, in transmission and in
reception, an actuator capable of selectively connecting the
antennae of the set to the operating electronics, and an antenna
monitor configured to regularly evaluate a reception quality
parameter for at least one sub-assembly of the set of antennae, to
repetitively select one or more antennae of the set as a function
of reception quality parameters derived from the sub-assembly and
to command the actuator to connect the selected antenna or antennae
to the operating electronics.
Inventors: |
Fraignac; Alexandre;
(Marolles-en-Hurepoix, FR) ; Mfoulou; Yannick;
(Massy, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Fraignac; Alexandre
Mfoulou; Yannick |
Marolles-en-Hurepoix
Massy |
|
FR
FR |
|
|
Assignee: |
VAM DRILLING FRANCE
Cosne Cours Sur Loire
FR
|
Family ID: |
47423020 |
Appl. No.: |
14/127584 |
Filed: |
June 22, 2012 |
PCT Filed: |
June 22, 2012 |
PCT NO: |
PCT/EP2012/062063 |
371 Date: |
January 7, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61536708 |
Sep 20, 2011 |
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61536763 |
Sep 20, 2011 |
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61536843 |
Sep 20, 2011 |
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Current U.S.
Class: |
340/854.4 |
Current CPC
Class: |
E21B 47/13 20200501;
E21B 17/003 20130101; E21B 21/106 20130101 |
Class at
Publication: |
340/854.4 |
International
Class: |
E21B 47/12 20060101
E21B047/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 2011 |
FR |
11 01924 |
Jun 22, 2011 |
FR |
11 01925 |
Jun 22, 2011 |
FR |
11 01926 |
Claims
1-19. (canceled)
20. An element for a drill string, comprising: a body with a
generally axisymmetric appearance; and a wave type communication
device installed in the body, wherein the communication device
comprises: a set of antennae including a plurality of antennae
distributed at a periphery of the body, about an axis of symmetry
thereof, and configured to operate in transmission and in
reception; operating electronics configured to organize transfer of
data, in transmission and in reception; an actuator configured to
selectively connect the antennae of the set to the operating
electronics; an antenna monitor configured to regularly evaluate a
reception quality parameter for at least one sub-assembly of the
set of antennae, to repetitively select one or more antennae of the
set as a function of reception quality parameters derived from the
sub-assembly, and to command the actuator to connect the selected
antenna or antennae to the operating electronics.
21. An element according to claim 20, wherein the selected antenna
or antennae include one or more antennae selected from the
sub-assembly and/or one or more antennae close to the antennae of
the sub-assembly.
22. An element according to claim 20, wherein the antenna monitor
is further configured to regularly evaluate a switching criterion
and to operate the actuator each time the switching criterion is
verified.
23. An element according to claim 22, wherein the switching
criterion includes a comparison between a time elapsed from a last
activation and a predetermined time period.
24. An element according to claim 23, wherein the predetermined
time period is calculated from a value for the rate of rotation of
the body, taking into account the distribution of the antennae
about the axis of symmetry of the body.
25. An element according to claim 24, wherein the value for the
rate of rotation is determined from a change with time of a
reception quality parameter of at least one of the activated
antennae.
26. An element according to claim 22, wherein the switching
criterion includes a comparison of substantially instantaneous
values for the reception quality parameters relating to the
activated antennae and to the other antennae of the
sub-assembly.
27. An element according to claim 20, wherein the operating
electronics is configured to toggle repetitively between a
reception mode and a transmission mode.
28. An element according to claim 27, wherein the operating
electronics are configured to operate in transmission mode for a
time period of a predetermined duration and to toggle into
transmission mode in absence of modification of the antennae to
which it is connected during the time period.
29. An element according to claim 20, wherein the set of antennae
includes a plurality of surface antennae distributed regularly
about the axis of symmetry of the body.
30. An element according to claim 20, wherein the body houses a
safety valve.
31. A device for a well head, comprising at least one element
according to claim 20.
32. A device according to claim 31, wherein the body of the element
includes an upper end threading, a lower end threading, an end
coupler, arranged at its lower end, configured to cooperate with a
matching end coupler of another element made up onto the lower end
threading, and an electrical connection arranged between the end
coupler and the operating electronics.
33. A device according to claim 32, further comprising a valve
arranged in an intermediate portion of the body between the upper
end threading and the lower end threading.
34. A well head device comprising at least one device according to
claim 31, attached to a drive in rotation with respect to a derrick
and one or more antennae that are fixed with respect to the
derrick.
35. A method for communication by a drill string element including
a body with a generally axisymmetric appearance and a set of
antennae, including a plurality of antennae distributed at a
periphery of the body about its axis of symmetry, and configured to
operate in transmission and reception, the method comprising: a)
evaluating at least one reception quality parameter for at least
one sub-assembly of the set of antennae; b) selecting one or more
antennae of the set as a function of the reception quality
parameter or parameters derived from the sub-assembly; and c)
organizing a transfer of data, in transmission and/or reception,
via the selected antenna or antennae.
36. A method according to claim 35, wherein the evaluation is
regularly carried out.
37. A method according to claim 35, wherein the selection is
carried out repetitively.
38. A method for drilling, exploration, and/or operation of a
hydrocarbon well, comprising one or more communication actions
carried out in accordance with the method of claim 35.
Description
[0001] The invention relates to deep or long wells, in particular
oil wells.
[0002] As an oil well advances, from time to time one or more tubes
have to be added at the well head. For this reason, such a well
comprises a vertical support structure on the surface which is
known as a derrick.
[0003] In general, the derrick and the equipment it contains, in
particular the rotary drive system, will be known herein as the
"well head equipment".
[0004] As will be seen in more detail below, the area of the well
head equipment is a cramped space. The derrick carries a mechanical
system which can hold the drill string as well as lift and drop it.
When pulling the drill string, the upwards vertical excursion is
ten metres or more. This is also the case for the downwards
vertical excursion during drilling.
[0005] The well head equipment also includes the rotary drive for
the string, for drilling, and also the system that can break out
and make up one or more tubes (or other equipment) onto the formed
string. To this is added a system for injecting and recovering
drilling mud which in particular actuates the drill bit. Finally,
various types of safety systems are necessary.
[0006] The search is currently on to make the drill string
communicative, so that information can be exchanged between the top
and bottom of the well or between intermediate equipment inserted
in the string. To this end, within the string, each tube is
provided with communication couplers at its ends and an electrical
connection between those couplers.
[0007] At the top of the well, it is helpful to pass data between
the string, which rotates and is displaced vertically, and fixed
electronic equipment on the surface. The connection between the
string and this surface electronic equipment is known herein as the
"surface interface".
[0008] Selecting this surface interface connection is critical. If
this connection is interrupted, the communication equipment
provided in the string itself becomes useless and all of the
information and commands it relies upon is lost.
[0009] A number of solutions can be envisaged. Of these, few are
actually applicable in practice, due to the many constraints placed
upon it, in particular the cramped environment of the well head
equipment.
[0010] As an example, US 2010/0214121 describes a drill string
provided with a communication device comprising a single
transmitter capable of carrying out wireless transmission with one
or more fixed "coordinators". Said coordinators are in fact
receiving antennae located at the well head. The envisaged
transmission conforms to IEEE standard 802.15.4, which allows data
transfer at a fairly low rate.
[0011] The communication device in question uses control or marker
signals originating from the coordinators in order to determine the
best available coordinator and/or, for one coordinator in
particular, the best moment to transmit data to it.
[0012] Data transmission is limited to a portion of the rotational
gate of the string, typically an arc of 120.degree., or to certain
time periods. This is intended to minimize the energy consumed for
data transmission.
[0013] It is then necessary to adjust the transmitter on the
coordinators to determine the time periods which are favorable for
data transfer: once a valid coordinator has been detected, the rate
of rotation of the string is used to determine a succession of
transmission time periods which correspond to successive passes of
the transmitter in the vicinity of the coordinator in question.
[0014] The device known from US 2010/0214121 suffers from a number
of disadvantages.
[0015] As has been seen, the rate of rotation of the string must be
known, but it is likely to vary with time, for example as drilling
problems crop up. Typically, supplemental sensors have to be
installed in the string, which causes problems with integration
thereof and electrical supply thereto.
[0016] Further, for high rates of rotation, little time is
available to carry out data transfer properly.
[0017] It also appears that the device in question only
accommodates a fairly reduced transfer rate, which may prove to be
insufficient, primarily because of recent improvements in the field
of sending information from the well bottom.
[0018] Finally, it is not a simple matter of multiplying the number
of coordinators, i.e. the receiving antennae, since as has been
seen above, the environment of the well head equipment is already
very cramped and filled with elements that are vital to the
drilling operations.
[0019] US 2010/0224409 A1 describes a wear insert or saver sub
which is used to connect the drill string to the drive system. Said
wear insert is equipped with antennae which allows wireless data
transmission with a surface antenna produced in the form of a
parabolic antenna. According to US 2010/0224409 A1,
transmission/reception of data can be carried out in practically
any direction, in particular over 360.degree. around the wear
insert, which means that communication should be established even
when the wear insert is driven in rotation or displaced in any
manner. The function of said antennae is not explained in more
detail. The idea appears to be to irradiate the antennae array
around the wear insert as widely as possible in all directions so
that the parabolic antenna can practically always capture data
transmitted by the insert in question. The system in US
2010/0224409 A1 does not overcome certain problems which arise in
practice in the art, such as the energy consumption of the onboard
electronic elements or the cramped space in the well environment,
to mention just a few.
[0020] The present invention will improve the situation.
[0021] It proposes an element for a drill string of the type
comprising a body with a generally axisymmetric appearance and a
wave type communication device installed in said body. This element
is remarkable in that the communication device comprises a set of
antennae comprising a plurality of antennae distributed at the
periphery of said body, about the axis of symmetry thereof, and
capable of operating in transmission and in reception, operating
electronics which are capable of organizing the transfer of data,
in transmission and in reception, an actuator which is capable of
selectively connecting the antennae of said set to the operating
electronics, and an antenna monitor arranged to regularly evaluate
a reception quality parameter for at least one sub-assembly of the
set of antennae, to repetitively select one or more antennae of
said set as a function of reception quality parameters derived from
said sub-assembly and to command the actuator to connect the
selected antenna or antennae to the operating electronics.
[0022] The proposed element allows communication between the drill
string and one or more fixed devices on the surface, at an
excellent rate and with a low energy consumption.
[0023] Optional characteristics of the invention, which may be
complementary, supplemental or substitutional, are mentioned below:
[0024] the selected antenna or antennae comprise one or more
antennae selected from said sub-assembly and/or one or more
antennae close to the antennae of said sub-assembly; [0025] the
antenna monitor is also arranged to regularly evaluate a switching
criterion and to operate the actuator each time the switching
criterion is verified; [0026] the switching criterion comprises a
comparison between a time elapsed from the last activation and a
predetermined time period; [0027] the predetermined time period is
calculated from a value for the rate of rotation of said body,
taking into account the distribution of the antennae about the axis
of symmetry of the body; [0028] the value for the rate of rotation
is determined from the change with time of the reception quality
parameter of at least one of the activated antennae; [0029] the
switching criterion comprises a comparison of substantially
instantaneous values for the reception quality parameters relating
to the activated antennae on the one hand and on the other hand to
the other antennae of said sub-assembly; [0030] the operating
electronics are capable of toggling repetitively between a
reception mode and a transmission mode; [0031] the operating
electronics are arranged to operate in transmission mode for a time
period of a predetermined duration and to toggle into transmission
mode in the absence of modification of the antennae to which it is
connected during said time period; [0032] the set of antennae
comprises a plurality of surface antennae distributed regularly
about the axis of symmetry of said body; [0033] the body houses a
safety valve.
[0034] The invention also concerns a well head device comprising at
least one drill string element as proposed above, as well as a well
head comprising at least one such device attached to a drive for
rotation with respect to a derrick and one or more antennae fixed
with respect to said derrick.
[0035] The body of the element may then have an upper end
threading, a lower end threading, an end coupler, arranged at its
lower end, intended to cooperate with a matching end coupler of
another element made up onto the lower end threading, and an
electrical connection arranged between the end coupler and the
operating electronics. The device may also comprise a valve
arranged in the intermediate portion of the body between the upper
end threading and the lower end threading.
[0036] The invention also pertains to a method for communication by
means of a drill string element comprising a body with a generally
axisymmetric appearance and a set of antennae, comprising a
plurality of antennae distributed at the periphery of said body
about its axis of symmetry, and capable of operating in
transmission and reception, comprising a step of evaluating at
least one reception quality parameter for at least one sub-assembly
of the set of antennae, a step of selecting one or more antennae of
said set as a function of the reception quality parameter or
parameters derived from said sub-assembly, and a step of
organization of a transfer of data, in transmission and/or
reception, via the selected antenna or antennae.
[0037] The evaluation step may be carried out regularly and/or the
selection step may be repetitive.
[0038] The invention also pertains to a method for drilling,
exploration and/or operation of a hydrocarbon well, comprising one
or more communication actions carried out in accordance with the
above method.
[0039] Further characteristics and advantages of the invention will
become apparent from the following detailed description and the
accompanying drawings in which:
[0040] FIG. 1 is a simplified view in side elevation of well head
equipment with a traditional rotary table drive;
[0041] FIG. 2 is a diagram of the made up components used at the
head of a drill string in the case of the well head equipment of
FIG. 1;
[0042] FIG. 3A shows a modern top motor drive in isometric
perspective;
[0043] FIG. 3B shows the upper portion of the drive of FIG. 3A;
[0044] FIG. 3C shows the lower portion of the drive of FIG. 3A;
[0045] FIG. 4 shows the made up components used at the string head
in the case of the drive of FIG. 3;
[0046] FIGS. 5A and 5B are two detailed partial views of well head
equipment equipped with the drive of FIG. 3;
[0047] FIGS. 6A and 6B respectively represent two variations of a
drill string element viewed in isometric, partially truncated
perspective;
[0048] FIG. 7A represents a simplified block diagram of the of the
elements of FIGS. 6A and 6B;
[0049] FIG. 7B represents a variation in a view analogous to that
of FIG. 7A;
[0050] FIG. 8 represents a block diagram of the onboard electronics
in the elements of FIGS. 6A and 6B;
[0051] FIG. 9 represents a block diagram of the surface electronics
for use in combination with the elements of FIGS. 6A and 6B;
[0052] FIG. 10 illustrates an example of an embodiment of a portion
of the electronics of FIG. 8;
[0053] FIGS. 11 to 13 are flow diagrams illustrating the function
of the onboard electronics of FIG. 10;
[0054] FIG. 14A represents a tubular insert in longitudinal
section;
[0055] FIG. 14B represents a variation of the insert in a view
analogous to FIG. 14A.
[0056] The accompanying drawings essentially contain elements of a
concrete nature. As a consequence, they not only serve to provide a
better understanding of the detailed description below, but also
contribute to the definition of the invention if necessary.
[0057] The established terminology for oil drilling is in English,
and many of these English terms do not have a general equivalent in
French. For this reason, in the present description and for the
purposes of clarity, a technical expression from the French will
very frequently be accompanied by the corresponding dedicated
English expression.
[0058] In FIG. 1, the well head equipment as a whole is designated
by the reference numeral 1. It includes the well-known slender
pyramid, or derrick 10, at the top of which is an idler sheave 11
housed in a crown 12. The idler sheave 11 supports by cable a
terminal sheave or travelling block 14. This assembly forms a hoist
which in its turn supports a pivot 20 termed a swivel, which in
turn supports an assembly which will be described in further detail
below and which comprises a drive system, known as a kelly drive
or, more briefly, a kelly. This kelly 21 cooperates with a rotary
table 23; its rotary drive is indicated here by a peripheral ring
25 one roller of which is mechanically driven by a chain or belt
via an intermediate pulley 24 the shaft of which is in turn driven
from the pulley of the output of motor 2. The rotary table 23 is
located in the region of a floor 22 of the derrick 10.
[0059] At the bottom in the example, the drill string commences at
ground level with a casing head 29 attached to the casing 30 of the
well. The string or chain of tubes 26, termed the drill string,
passes inside this casing 30 and terminates in a drill bit 27
constituted, for example, by rotary abrasive disks.
[0060] The idler sheave 11 is driven by a hoist 16 driven by a
motor, which is not shown. The reference numeral 15 designates the
cable which supports the drill string via the travelling block 14
and the idler sheave 11.
[0061] The drill bit 27 requires energy to function and this energy
is transmitted to it by pressurized mud and/or by various rotary
mechanisms located on the surface or along the drill string, for
example one or more motors. Mud is withdrawn from a reservoir 40
via an intake line 41 and is moved to a pump 42 driven by a motor,
not shown. This mud lubricates the drill bit 27, cools it, lifts
debris from the well bottom, equilibrates its pressure, cleans it
and drives some of the equipment of the drill string.
[0062] At the outlet from the pump 42, pipework rises along a wall
of the derrick 10, ending in a gooseneck 43 from which the pipework
drops and rises again to another gooseneck 45, and is attached to
the top of the swivel 20 so that mud can enter the string, passing
through the kelly 21 to the casing head 29.
[0063] The mud then drops through the drill string 26 to cause the
drill bit 27 to function. It rises between the string 26 and the
casing 30, to the casing head 29, where it is taken up through two
safety devices 33 of the valve type, known as blow out preventers:
one, known as the blind ram, is capable of crushing the casing 30
annularly to isolate it while the other, termed the shear ram, is
capable of severing and closing off the assembly formed by the
casing 30 and the string 26.
[0064] The mud then rises towards a type of expansion vessel 31
known as a bell nipple, from which it passes into a return line 47
before returning to the reservoir 40 through a device 49 which
filters the mud. Gases are filtered out and debris is
eliminated.
[0065] On the left hand side, the floor 22 is extended at 50 to act
as a support for a tube stand 51 held at the top by racking 52
known as a finger board.
[0066] It will be understood from the foregoing that between the
travelling block 14 and the string 26, at the head of this string,
there are elements which provide the rotary drive for said string
26. The elements which are driven are included within the dashed
outline, and in this case include the swivel 20, the kelly 21, the
rotary table 23 and the peripheral ring 25.
[0067] The moving elements, from the central column of the derrick
to the travelling block 14, in particular the swivel 20 and the
kelly 21, undergo a vertical excursion of ten metres or more.
[0068] The derrick houses other elements, not shown in FIG. 1:
[0069] a system for supporting the drill string 26, when it is
disconnected from the hoist; [0070] equipment for manipulating the
tubes between the store 51 and the central column; [0071] a system
which can carry out breakouts or makeups on the drill string 26 in
order to add or remove a length of tube; [0072] safety valves, in
particular installed at the top of the drill string; [0073] a
hydraulic clamp to hold the tubes when being made up on the
drive.
[0074] Reference will now be made to FIG. 2. The central portion
shows the profiled drive stem termed the kelly. It is a long stem
with a polygonal cross section, in principle square or hexagonal,
denoted KD_I on FIG. 2. This stem is attached to threaded end
shanks denoted KD_U at the top and KD_L at the bottom. The assembly
formed by the stem KD_I and its ends KD_U and KD_L is generally
denoted the KD (for kelly drive).
[0075] The top threading of the upper shank KD_U engages with an
upper wear insert, denoted USavSub, surmounted by an upper safety
valve termed the upper kelly valve, denoted UKV, and which in
principle is actuated manually. At the bottom of the profiled stem
KD_I, its lower shank KD_L engages with a lower safety valve termed
the lower kelly valve, denoted LKV, which in principle is pneumatic
in action, followed by a lower wear insert, LSavSub, to which the
drill string 26 will be attached.
[0076] The lower wear insert LSavSub may also act as an adapter for
the threading. Its lower threading has to be compatible with the
threading specified for the string 26. In contrast, its upper
threading may be different.
[0077] The manual valve may in particular be used as a safety valve
in the event of the pneumatic valve not closing off the well
completely.
[0078] It has been shown that in the well heads of FIGS. 1 and 2,
drive is obtained via a rotary table 23; its rotational motion is
transmitted to the profiled stem KD_I. A removable bushing (kelly
bushing), not shown, defines a profile with a shape corresponding
to the square or hexagonal profile of the stem KD_I. The kelly
bushing is inserted between the rotary table 23 and said profiled
zone KD_I. Thus, the rotary table 23 drives the profiled stem KD_I
in rotation while leaving it free in vertical translation to
accompany the descent of the drill string 26 as drilling
progresses.
[0079] Tubes are added as drilling progresses.
[0080] Consider now the time when one or more tubes are to be added
to the string. The profiled stem KD_I is then completely out of the
well and the rotary table 23 is engaged at the bottom of its
profiled zone. This is the "top position" of the drill string 26.
The stem KD_I descends by sliding as drilling progresses until the
top of its profiled zone engages with the rotary table. This is the
"bottom position" of the drill string 26. It is then time to add
another tube or tubes. To this end, rotation (drilling) is halted,
and the kelly bushing is removed; the string 26 is lifted to a
height substantially equal to the length of the profiled stem KD_I;
the string 26 is locked under the stem KD_I; and the stem KD_I is
broken out from the string. A new tube is made up at the top of the
string 26. The string 26 is dropped again by the height mentioned
above, so that the drill bit 27 is once again at the well bottom.
The stem KD_I is made up again onto the top of the string. The
kelly bushing is replaced to provide the rotational coupling of the
KD_I to the rotary table 23. Drilling can then resume.
[0081] Events are substantially similar, with the vertical
displacements in the reverse order, when the drill string 26 is to
be removed completely or partially. Known techniques allow the
casing to be deposited sequentially after drilling a section of the
well (to depth).
[0082] As drilling progresses, there will thus be many
breakout/makeup operations on the same threading of the same
component. These breakout/makeup operations are carried out under a
high load due to the weight of the string, which may in the end
comprise a hundred or several hundred tubes, and hence wear of the
threading is rapid. For this reason, it is normal to use one or
more wear inserts, known as saver subs, at regions which undergo
repeated breakout/makeup operations. In the case of FIGS. 1 and 2,
there are two wear inserts respectively placed at the top (USavSub)
and the bottom (LSavSub) of the profiled stem KD_I, or kelly. These
upper and lower inserts with respect to the profiled stem KD_I are
respectively known in the art as the "upper kelly saver sub" and
the "lower kelly saver sub".
[0083] Reference will now be made to FIGS. 3A, 3B and 3C, which
illustrate a more modern embodiment of the well head equipment.
[0084] In recent wells, the well head equipment is equipped with a
top drive system, denoted TD, shown in its entirety in FIG. 3A. The
drive is mounted right at the top of the drill string, supported
directly by the travelling block 14 by means of a system bail SB
attached to it.
[0085] In its upper portion, shown in isolation in FIG. 3B, the top
drive system TD comprises an electric motor DM (drilling motor)
which drives a drive stem DS in rotation via a transmission TR.
This upper portion also comprises a pair of hydraulic brakes HB as
well as a cooling system comprising a pair of cooling ducts CD
(cooling system air duct) connected to the motor DM and in which
air moves by the action of the fans CF (cooling fan motor).
[0086] The stem DS is hollow. For the reasons given above, mud is
injected into the stem DS by means of a gooseneck GS, via a bonnet
BO and a wash pipe packing assembly WP.
[0087] In its lower portion, visible in isolation in FIG. 3C, the
drive TD comprises a PEP (powered elevator positioner) motor which
can turn through 360.degree. about the axis of the stem DS. A
backup clamp BUC is connected to the positioner PEP via a torque
arrestor frame TAF. Elevators E provided with a hydraulic clamp HC
are mounted at the end of elevator links EL of which the opposite
end is attached to the positioner PEP via rotating link adapters
RLA. The adapters RLA can be used to pivot the arms EL with respect
to the axis of the drive stem DS under the action of a link tilt
assembly fixed to the positioner PEP. The backup clamp BUC
comprises adjustable stabilizing guides SG, not shown.
[0088] FIG. 3C also shows an upper safety assembly (upper blow out
preventer), UBOP, and a lower safety assembly (lower blow out
preventer), LBOP, interposed between the stem DS and a wear insert
(saver sub), which cannot be seen. The backup clamp BUC, disposed
above the hydraulic clamp HC, engages over practically the whole
wear insert.
[0089] The drive TD is guided by a laterally offset vertical rail
VR (FIG. 3A). The drive TD descends as drilling progresses until it
is close to the floor of the derrick 10. Adding a length of tube is
a little simpler than before. The drill string is locked by being
strongly clamped and it is broken out from the stem DS, more
exactly from a wear insert, termed the top drive saver sub, fixed
beneath the lower safety assembly LBOP. In this case, there is only
one wear component.
[0090] The motor is lifted towards the top of the derrick 10. One
or more tubes are added. Then the drill string is made up again
onto the wear component, remaining attached to the drive TD. The
assemblies UBOP and LBOP respectively comprise an upper safety
valve (upper kelly valve) UKV and a lower safety valve (lower kelly
valve) LKV disposed one above the other between the stem DS and the
wear insert SavSub. Conventionally, they retain their names "upper
kelly valve" and "lower kelly valve" even though there is no longer
a profiled stem known as a kelly in this embodiment.
[0091] FIG. 4 shows the arrangement of the column head in the case
of the well head equipment of FIGS. 3A to 3C.
[0092] The motor DM drives the stem DS which is threaded and
engages on the upper safety valve UKV. In this embodiment, it is
immediately followed by the lower safety valve LKV then the wear
insert SavSub, in this case just one.
[0093] As already indicated, the aim now is to render the string
communicative so as to be able to exchange information between the
top of the well on the one hand and the bottom of the well on the
other hand, or intermediate equipment inserted in the string. To
this end, within the drill string, each tube is equipped with
communication couplers (abbreviated to "couplers") at its ends and
with an electrical connection between said couplers.
[0094] Known solutions to this problem have been described, in
particular in the document "US DOE Report" with reference "Report
#41229R14". This document is available at the following internet
address: [0095]
http.//www.netl.doe.gov/technologies/oil-gas/publications/epreports/dcs/f-
inal%20report%20fg123104.pdf
[0096] Those solutions suffer from a number of disadvantages.
[0097] One of these solutions, known by the name "SwivelLink",
integrates rotary union type transmission electronics into a
specialized insert or sub, which will naturally be quite lengthy,
in order to be able to house the transmission electronics. The
internal cross section of flow has to be retained for the drilling
mud in particular. The transmission electronics are located in a
housing provided in the peripheral tubular wall of the insert,
hence the length.
[0098] Using that first solution involves a complete rethink of the
architecture of the well head equipment because of said length.
This considerably limits the scope of this solution. Further, it
involves revising all of the standards applicable to the well head
elements, which has considerable consequences in terms of
costs.
[0099] If, in contrast, this first solution were to be integrated
into the top drive system of an existing well using current
standards, then one of the top elements of the string would have to
be sacrificed: by removing one of the two safety valves UKV and
LKV, or by replacing the wear insert SavSub.
[0100] The document Report #41229R14 also describes a second
solution, known as "Data Swivel", where the wear insert known as
the saver sub is provided with an electrical rotary union wherein a
portion which is fixed with respect to the derrick 10 is connected
to a fairly long cable to accommodate the vertical excursion of the
wear component during drilling.
[0101] However, as can be seen in FIG. 4, the backup clamp BUC
engages on the wear insert over practically its entire length.
Thus, there is a major risk of deterioration of the electrical
rotary union and/or the cable carried by it when the wear insert is
clamped by the hydraulic backup clamp. This deterioration is
disastrous as the whole communication system of the drill string is
then cut off. For the reasons given above, the wear insert cannot
be lengthened, especially because the backup clamp BUC is at a
fixed distance with respect to the remainder of the top drive TD:
[0102] elongating the wear insert towards the top of the drill
string would involve removing or shortening the elements which are
normally located there even though they are safety devices; this
would also mean that specific elements would have to be produced,
and finally, almost all of the string head, the wear insert and the
drive stem would have to be changed; [0103] elongation of the wear
insert towards the bottom of the drill string would cause analogous
disadvantages since the distance from the drive stem to the
hydraulic clamp is also fixed.
[0104] Thus, at the moment, there are no completely satisfactory
practical solutions.
[0105] The present invention will improve the situation. It will be
described for the case of modern well head equipment in accordance
with the principles shown diagrammatically in FIG. 3, i.e. with a
top drive.
[0106] The Applicant carried out an in-depth examination of the
practical function of the elements used in the cramped environment
of a well head.
[0107] Known solutions are limited by the fact that the skilled
person will not in principle modify a safety means in a substantial
manner. Thus, in the second solution mentioned above, the rotary
union has been installed in the wear component termed the saver
sub, although it will encounter an environment which is dangerous
for its rotary union.
[0108] Unexpectedly, the Applicant's studies have shown that it is
possible to incorporate a rotary union into a safety valve of the
kelly valve type, in contrast to that which would a priori have
been assumed to be the case.
[0109] This is what will now be described with reference to FIGS.
6A and 6B.
[0110] These FIGS. 6A and 6B show a safety valve which in this case
is the safety valve LKV of FIG. 4. In conventional manner, it
comprises a generally tubular structure or body 600 with an
internal threading 601 at one end (upper end in FIGS. 6A and 6B)
and an external threading 602 at its opposite end (lower end in
FIGS. 6A and 6B).
[0111] In the intermediate portion, a spherical bead 610 is
pivotally mounted in a guide 611. This is introduced by sliding it
into the body 600 until it abuts against a shoulder 614. On the
opposite side, the guide 611 is retained by a ring 618 housed in a
peripheral groove provided inside the body 600. The spherical bead
610 is pierced with a cylindrical channel 613 with the same
geometry as the interior of the body 600. In the example shown,
pivoting of the bead may be controlled via an actuator having a
hexagonal profile matching the indented shape 612 formed in the
spherical bead 610. The spherical bead 610 can be pivoted between a
position where the channel 613 is in the axis of the body 600 and a
position where the spherical bead 610 obscures the interior of the
body 600.
[0112] The Applicant has observed that the lower end of the valve
LKV may be provided with a coupler 626 similar to the couplers used
in the drill string. This coupler 626 is connected to a first
electrical connection 624 having a longitudinal piercing, provided
in the annular wall of the body 600 then a radial piercing which
extends at a right angle until it reaches a recess 623 provided on
the outer wall of the body 600. The recess 623 houses onboard
electronics 621 which are connected via a second electrical
connection 625 to a set of antennae 627 housed in an annular groove
629 also provided on the periphery of the body 600. The second
electrical connection 625 has a longitudinal piercing provided in
the annular wall of the body 600 and a radial piercing which
extends at a right angle to the annular groove 629. The annular
groove 629 is closed by a protective means which in this case is
produced in the form of a cover 628 formed from a non-metallic
material, for example formed from polytetrafluoroethylene
(PTFE).
[0113] The recess 623 is closed by a protection which in this case
is in the form of a cover 630 formed from an amagnetic material,
for example a metallic material. The cover 630 is held on the body
600 in a leak-proof manner by means of a seal (not shown) and a set
of screws. The thickness of the protection is adapted so as to
guarantee it sufficient mechanical strength for the pressure and
the torque produced.
[0114] The onboard electronics 621 and the set of antennae 627 form
part of a wireless communication device which, in general, can be
used to transmit data originating from the drill string to a
surface network and to receive data originating in this surface
network. The wireless communication device in question forms a part
which may be termed a surface interface.
[0115] In the embodiment of FIG. 6A, the onboard communication
device in the body 600 is intended to cooperate with at least one
wire antenna 631, for example a leaky feeder, fixedly held in the
well head equipment. The wire antenna 631 extends along it for at
least the vertical excursion executed repetitively by the valve
LKV, along with the top portion of the drill string. This excursion
may be as long as several tens of metres depending on the drive
technique employed.
[0116] In the embodiment of FIG. 6B, the onboard communication
device in the body 600 is intended to cooperate with a surface
communication device 632 which may be provided with a grommet (not
shown) through which a vertical cable passes. The surface
communication device 632 may remain fixed at the base of the well
head equipment during the combined movements of sinking or rising
and rotation executed by the valve LKV with respect to the derrick
10.
[0117] As can be seen in FIG. 4, the tubular element SavSub located
below the safety valve LKV is normally a wear insert, or saver
sub.
[0118] The Applicant has observed that the two ends of this wear
insert could be provided with communication couplers while a
connection between them passes along the wear insert, preferably in
a channel pierced in the wall thereof, from one end to the
other.
[0119] We shall now describe this with reference to FIG. 14A.
[0120] This FIG. 14A shows a wear insert which in this case is the
wear insert SavSub of FIG. 4.
[0121] In conventional manner, the insert SavSub comprises a
generally tubular structure 1400 with a threading 1401 at the upper
end, compatible with the threading 602 of the lower end of the
safety valve LKV, and a threading 1402 at the lower end. The
threading 1402 of the lower end of the insert SavSub is compatible
with the threadings used in the lower portion of the string.
[0122] The lower end of the insert SavSub is provided with a
coupler 1426 similar to those which are used in the drill string.
The upper end of the insert SavSub is provided with a coupler 1427
matching the coupler 626 of the safety valve LKV. In this case, the
coupler 1427 at the upper end and the coupler 1426 at the lower end
of the insert SavSub are analogous. These couplers are connected
together by an electrical connection 1424 having a longitudinal
piercing provided here in the annular wall of the tube.
[0123] In particular, the lower coupler 1426 of the insert SavSub
may have the same dimensions as the couplers which are used in the
drill string, while the upper coupler 1427 of the insert SavSub and
the lower coupler 626 of the valve LKV may also have the same
dimensions as those which are used in the drill string.
[0124] FIG. 14B shows a variation of the insert SavSub which
differs from that illustrated in FIG. 14A in that its threading
1401 at the upper end is male in type rather than female. In this
form, it is adapted to a valve LKV for which the lower end
threading 602 is female in type. This means that the upper end
coupler 1427 is housed close to the corresponding terminal face of
the insert SavSub, while in the embodiment of FIG. 14A, this
coupler 1427 is housed at the bottom of a bore provided to receive
the lower end of the valve LKV. In other words, in FIG. 14B, the
coupler 1427 at the upper end is close to the end of the threading
1401 which is distant from the lower end of the insert SavSub,
while in FIG. 14A, this coupler 1427 is close to the end of the
threading 1401 which is close to the lower end of the insert
SavSub.
[0125] Reference will now be made to FIG. 7A.
[0126] The set of antennae 627 comprises a plurality of elementary
antennae 700-i (i being a whole number from 1 to N, N being the
number of antennae in said set), which are flat, and are printed on
a substrate 702 and covered with a cover layer 704 produced from a
non-metallic material. The cover layer 704 may be different from
the protective means 628 (not shown in FIG. 7A).
[0127] The elementary antennae 700-i are disposed in a regularly
distributed manner around the axis of symmetry of the body 600. The
right hand portion of FIG. 7, which represents a portion of the set
of antennae 627 in a developed form, shows, by way of example,
elongated elementary antennae 700-i each being inclined with
respect to the longitudinal direction of the body 600 such that
each end of an elementary antenna 700-i is approximately aligned in
the direction of the axis of symmetry of the body 600 in each case
with a respective end of an adjacent elementary antenna 700-i. With
such a disposition, the set of antennae 627 radiates in a
substantially identical manner over the whole of the circumference
of the body 600, at least over a longitudinal section of the body
600 comprising the set of antennae 627.
[0128] As an example, in this case the set of antennae 627
comprises eight elementary antennae 700-i (N=8).
[0129] In a variation illustrated in FIG. 7B, the elementary
antennae 700-i are flat antennae, also known in the art as patch
antennae. These antenna can be used to produce antennae with good
directional properties in a reduced space.
[0130] In this case, the flat antennae are rectangular leaky feeder
antennae connected into an array via a set of hybrid couplers (not
shown).
[0131] FIG. 8 illustrates the function of a set of components 800
for the onboard electronics 621.
[0132] The set of components 800 comprises a first transceiver
circuit 810 connected in a two-way manner to the set of antennae
627, which manages the communication between the set of antennae
627 and the fixed antenna installed on the well head equipment, and
a second transceiver circuit 804 in charge of the two-way
transmission of data with the devices installed in the drill
string, which devices are represented as a whole by the dashed line
frame with reference numeral 806.
[0133] The set of components 800 also comprises a memory 808 in
which useful data can be stored, in particular data originating
from the drill string to be transmitted to the surface network and
data originating from this network to be routed to the drill
string. As an example, the memory 808 acts in the manner of a
buffer memory.
[0134] The set of components 800 also integrates one or more
batteries 814 which supply the onboard electronic elements 621
including a microprocessor 802 which makes all of these elements
operate in an integrated manner.
[0135] As an option, the set of components 800 comprises a "local"
communication interface 816 connected to sensors installed in the
valve LKV and which measure the functional characteristics of the
onboard electronics 621 and/or the valve LKV itself. These
characteristics may, in a non-limiting manner, comprise data
regarding the vibrational characteristics of the valve LKV, the
pressure inside said valve, or the temperature.
[0136] Optionally again, the set of components 800 comprises a
configuring interface 818 through which the microprogram of the
microprocessor 802 may be updated and/or data can be recovered from
the memory 808 and/or the onboard electronics 621 or even the valve
LKV itself, can be tested and/or configured, inter alia.
[0137] FIG. 9 represents the function of surface electronics 900
which cooperate with one or more fixed antennae with a view to
communicating with the onboard device in the valve LKV. The surface
electronics 900 also form a part of the device termed the surface
interface.
[0138] The surface electronics 900 comprise a central processing
unit 902 supplied via a current transformer 904 connected to an
energy distribution network shown as the dashed line frame with
reference 906. Replacing it or as a complement to it, the surface
electronics 900 may be provided with one or more batteries, in
particular as an energy source if the power distribution network
should fail.
[0139] The surface electronics 900 integrates a transceiver circuit
908 which provides digital type two-way communication with the
processing unit 902 and two-way communication with the antenna 910,
which latter may be of the wire type as in the embodiment of FIG.
6A or of another type, for example in accordance with the
embodiment of FIG. 6B.
[0140] The surface electronics 900 also include a second
input/output interface, in this case of the Ethernet type,
connected to a data exchange network represented here as the dashed
line block 914, and a configuration circuit 916 connected to the
processing unit 902 and optionally accessible via a standard type
input/output interface, for example of the USB (universal serial
bus) type.
[0141] FIG. 10 shows a portion of the set of components 800
intended to transmit/receive data via the set of antennae 627.
[0142] The transmission lines for the various elementary antennae
700-i are respectively referred to therein as 100-1, 100-2, . . .
100-8.
[0143] Each transmission line 100-i (i=1, . . . , 8) is connected
to a respective switching gate of a switching circuit 102 including
an input/output gate which is connected to an input/output gate of
a two-way switch 106. The switching circuit 102 is capable of
selectively connecting, in this case under the control of a
microprocessor 104, one or more transmission lines 100-i to the
input/output of the switch 106.
[0144] The switch 106 has a first switching gate connected to a
reception line 107 and a second switching gate connected to a
transmitting line 111. Under the control of the microprocessor 104,
the switch 106 can pass from a first switching state in which the
reception line 107 is connected to the input/output gate of the
switching circuit 102, the set of antennae 627 thus acting in
reception mode, to a second switching state in which the
transmission line 111 is connected to the input/output gate of the
switching circuit 102, the set of antennae 627 then operating in
transmission mode. The switch 106, the reception line 107 and the
transmission line 111 form operating electronics which are capable
of operating in transmission or reception mode depending on the
switching state of the switch 106.
[0145] Although in this case the microprocessor 104 controls both
the switching circuit 102 and the switch 106, in a variation, it is
possible to control both devices by means of distinct dedicated
microprocessors.
[0146] The reception line 107 comprises an amplifier-adapter 108
and a reception memory 110, while the transmission line 111
comprises an amplifier-adapter 112 and a transmission memory 114.
Although not shown in the figures, the amplifier-adapter 108 of the
reception line 107 and the amplifier-adapter 112 of the
transmission line 111 may be controlled by the microprocessor
104.
[0147] The reception memory 110 and the transmission memory 114 may
be organized within the same electronic device.
[0148] This portion of the set of components 800 also comprises a
detection circuit 118 to which each of the transmission lines 100-1
to 100-8 are connected via a respective input. The detection
circuit 118 is capable of establishing a signal representing a
reception power as measured at its inputs on each of the
transmission lines 100-1 to 100-8 corresponding to the elementary
antennae 700-i of the set of antennae 627 and, if appropriate, to
deliver that signal to the output, in this case the microprocessor
104.
[0149] FIG. 11 illustrates the function of the onboard electronics
as regards transmission and reception of data.
[0150] In an operation 1100, the onboard electronics 800 are
initialized at least as regards the elements described in relation
to FIG. 10. The transmission line is in reception mode (the switch
106 is on the reception line 107). The signal derived from the
detection circuit 118 is acquired.
[0151] An operation 1102 verifies whether the set of antennae is at
least partially operational, i.e. that at least one of the antenna
elements is capable of receiving a signal from the fixed antenna.
For example, the detection circuit 118 is checked as to whether it
measures a reception power value of more than a threshold value for
at least one of the elementary antennae 700.
[0152] If not, the operation 1102 is recommenced until at least one
antenna is operational.
[0153] When the test 1102 for operation is positive, during an
operation 1104, reception of a packet of data and transmission of
another packet of data are organized.
[0154] Next, the data received and/or the data to be transmitted to
the next transmission/reception step are processed during an
operation 1106. During this processing operation, it is in
particular checking if the packet of data received is integral, in
other words whether the data received form a complete packet.
Encapsulation of the data into packets for transmission is also
checked.
[0155] This succession of operations may be carried out in the form
of a function of a microprogram executed by the microprocessor 104.
However, there is no impediment to using exclusively electronic
logic circuits to carry it out.
[0156] FIG. 12 details the operation of transmission and reception
of a data packet.
[0157] This operation commences with an initialization step 1200.
This initialization step in particular comprises a phase for
synchronization between the onboard electronics 800 and the surface
electronics 900 in order to define respective time windows for
transmission and reception of a data packet.
[0158] In step 1202, the onboard electronics 800 are in a reception
state. This means that the switch 106 is switched onto the
reception line 107, which may undergo a supplemental test. In
practice, the switch 106 has a default switching state which
corresponds to the reception mode. The reception state also
involves operation of the amplifier-adapter 108. Received data are
written to the reception memory 110. This reception step is
finished when a time period t_r, set during the synchronization
with the surface electronics 900, has elapsed. We shall see below
how to evaluate this period t_r in an advantageous manner.
[0159] When the time t_r has elapsed, step 1204 tests whether,
during period t_r which has just elapsed, there has been a change
in state in the switching circuit 102.
[0160] If yes, then step 1202 is recommenced. In other words, the
onboard electronics 800 are once again placed in data reception
mode for a new time period t_r. The time t_r that this reception
period lasts may be subject to a new synchronization. In other
words, the duration of the reception time period may be adapted
each time that this step 1202 is recommenced. This means that the
fact that the switching circuit 102 may be switched too frequently
to allow reception of a complete data packet in the negotiated time
period t_r can be taken into account.
[0161] If the test of step 1204 is negative, then the onboard
electronics are toggled into transmission mode, in step 1208. This
means that the switch 106 is toggled onto its second switching gate
and that the amplifier-adapter of the transmission gate is made
operational. This packet transmission step is complete when a time
period t_s, the duration of which has been negotiated during the
preceding synchronization step, has elapsed.
[0162] When the time period t_s has elapsed, a test as to whether
there has been a switch in the switch 102 during this time interval
is carried out in step 1210.
[0163] If yes, then the transmission step 1208 is recommenced for a
new time period t_s, with a duration equal to or different from the
preceding time period t_s.
[0164] If the interval t_s has elapsed without an intervening
switch, then the set of antennae 627 is toggled into reception mode
during step 1212, i.e. the microprocessor 104 transmits a switching
signal to the switch 106 which links the reception line 107 to the
input/output gate of the switching circuit 102.
[0165] The steps just described may be carried out by executing a
function of a microprogram of the microprocessor 104.
[0166] FIG. 13 illustrates the function of the onboard electronics
as regards switching the elementary antennae 700-i of the set of
antennae 627.
[0167] After an initialization operation 1300, a test is carried
out as to whether the set of antennae is at least partially
operational during a step 1302.
[0168] In particular, this test consists of checking that a minimum
reception power can be measured on at least one of the transmission
lines 100-i (i=1, . . . , 8).
[0169] If the test of operation 1302 is negative, then operation
1302 is recommenced until it is positive, if necessary after a
delay.
[0170] In operation 1304, one or more selection criteria pertaining
to all of the elementary antennae 700-i that have been adjudged
operational is evaluated. At this moment, the best performing
antenna or antennae for communication are determined.
[0171] In one embodiment, the antenna line 100-i on which the
highest reception power is measured is selected. In this
embodiment, the available transmission power is concentrated on a
single elementary antenna 700, which means that very high
performance as regards rate and energy savings can be obtained.
[0172] In a variation, a sub-assembly of transmission lines could
be selected, for example all of the transmission lines for which a
reception power greater than a predetermined base value is measured
may be selected.
[0173] In yet another variation, it is also possible to select the
line on which the highest reception power is measured or several
lines on which the highest reception powers are measured, i.e.
higher than the reception powers measured on the other lines. In
this case, the selection may be conditioned by the fact that the
reception power measured on the selected lines is greater than a
base value for the power.
[0174] The selected antenna or antennae may also comprise one or
more elementary antennae close to the antenna corresponding to the
transmission line on which the highest reception power is measured,
in particular if several fixed antennae are used at the
surface.
[0175] In yet another variation, the power levels measured by the
detection circuit 118 may only be taken into account in a secondary
manner for the selection of the elementary antenna or antennae. As
an example, with the elementary antenna which is active at the
present moment being identified (for example by means of a stored
register), the elementary antenna selected in operation 1304 may be
the antenna adjacent to the current antenna (higher or lower
identifier) on the transmission line on which the highest reception
power is measured. Again as an example, with the currently active
elementary antenna and a direction of rotation of the body 600
(known by extrapolating the change in the reception power of an
antenna line, typically the antenna line which corresponds to the
currently activated antenna, and the change in slope) being known,
the antenna selected during operation 1304 may be the next antenna
(with a higher or lower identification number) provided that the
measured reception power is higher than a threshold value.
[0176] In operation 1306, the switching circuit 102 is commanded to
connect the switching gates corresponding to the transmission lines
of the selected antennae to its input/output gate.
[0177] Operation 1308 tests whether one or more switching
conditions are satisfied. These switching conditions are intended
to determine when it is opportune to carry out a modification to
the set of active antennae.
[0178] A first condition may comprise evaluating the reception
power of the currently active antenna and comparing the measured
power level with a base value, this first condition being satisfied
if the measured power is less than a base value.
[0179] A second condition may comprise comparing the reception
powers measured on the transmission lines corresponding to a
sub-assembly of the set of antennae 700. As an example, the second
condition is satisfied if there is a transmission line which is
different from the line corresponding to the currently active line
on which a reception power which is greater than the currently
active antenna is measured.
[0180] A third condition may include the elapse of a predetermined
time period, for example evaluated on the basis of a rate of
rotation of the body 600.
[0181] The operation 1308 is recommenced when the switching
conditions are not satisfied.
[0182] The operations described in relation to FIG. 12 may be
carried out by executing one or more functions of the microprogram
of the microprocessor 104, a microprocessor dedicated to
controlling the detection circuit and the switching circuit 102,
and/or a specific circuit.
[0183] The detection circuit 118, jointly with the microprocessor
104 with which it exchanges data, acts like an elementary antenna
monitor which repetitively evaluates the reception power of each of
these elementary antennae as regards being a reception quality
parameter, or of a sub-assembly of the set of antennae 627. The
detection circuit 118, jointly with the microprocessor 104,
repetitively selects one or more elementary antennae from said set
as a function of the reception quality parameters derived from said
sub-assembly and commanding the switching circuit 102, which acts
as an actuator, to connect the thus selected antenna or antennae
which may be called the operating electronics, i.e. the
transmission line 111 and reception line 108.
[0184] We shall now return to the processing step described above
in relation to FIG. 13.
[0185] Because the elementary antennae 700-i are distributed in a
regular manner about the axis of symmetry of the body 600, which
corresponds to its axis of rotation when the drill string is
working, this means that at all times the power level is higher
than a base level in transmission and in reception, at least when
the surface interface is functioning normally. By repetitively
switching the best performing active elementary antennae over an
interval of time, energy consumed by transmission of data is saved.
In other words, directive elementary antennae have been produced
which can, thus, be controlled in order to limit energy losses. On
this point, the use of high transmission frequencies, for example
of the order of 2.45 GHz, further improves the directivity of the
elementary antennae.
[0186] The minimum power level is maintained due to switching of
the active elementary antennae which is regular, selective and
conditional to a greater or lesser extent.
[0187] The switching frequency depends on many parameters,
especially the change in the conditions for the propagation of
radiofrequency waves in the well head equipment, which conditions
might be influenced by many fairly unpredictable parameters, such
as the presence of equipment between the body 600 and the fixed
antenna, for example. It should be noted that the negative effect
of these unpredictable phenomena on transmission is minimized
because generally, the best performing antenna or antennae are
switched (and not necessarily that facing the fixed antenna).
[0188] The rate of rotation of the body 600 with respect to the
fixed antenna may influence the frequency of switching of the
elementary antennae 700, and as a result the duration of the time
window effectively available for transmission and reception of
data.
[0189] Given a threshold transmission power level, above which it
is assumed that data transmission is opportune, the increase in the
rate of rotation of the drill string tends to reduce the time
window effectively available for an elementary antenna, while a
reduction in this rate tends to increase this time window.
[0190] Advantageously, the processing carried out on the data
packets can be adapted to take this into account.
[0191] In one embodiment, the data to be transmitted are
encapsulated into packets with a size that is likely to vary with
time as a function of the switching frequency, which may be
evaluated on the basis of a history (a mean of the switching
frequency in a past time interval, for example) or on that of a
rate of rotation. In other words, the size of the packets
transmitted and received is adapted as a function of the time
window offered each time by an elementary antenna 700.
[0192] It is also possible to provide fixed size packets. The
packet size may then be estimated on the basis of a maximum
rotation rate for the drill string, either real (for example 120
rpm) or theoretical (for example 250 rpm).
[0193] Within a time window, at least one interval is appropriately
organized for reception, with duration t_r, and an interval for
transmission, with duration t_s. These durations t_r and t_s may be
deduced, if necessary, from the time window available on an
elementary antenna 700, such that the duration of this window is
known, estimated, measured or assumed. The durations t_s and t_r
are not necessarily identical given that in the application
described here, the information to be extracted from the drill
string is greater in quantity than the information to be
transmitted to said string.
[0194] As has been seen, the solution proposed here is a complete
rethink of the usual ideas of the skilled person. This comes
firstly from the provision of a communication device on a safety
element, namely a valve.
[0195] In contrast, known solutions, in particular US 2010/0224409,
place the rotary union on the wear insert even though this is
located close to mechanical means operating under load, such as the
hydraulic clamp. There is thus a serious risk of damage to the
rotary union and its connection cable with the surface interface,
and thus of inadvertent interruption to service.
[0196] Further, it is normal to periodically "recondition" the
threadings of the wear insert. The presence of an electrical union
on it poses problems if its threadings are to be reconditioned
under economically acceptable conditions. The variation consisting
of making the wear component a dispensable component is also not
economically desirable.
[0197] US 2010/0224409 proposes the production of a communication
device which is at least partially removable, but this renders
manufacture of the wear insert still more complex.
[0198] The solution proposed here avoids this problem. The wear
insert is provided with end couplers and a cable, in a manner
similar to that for the tubes of the drill string. It does not have
the outer projecting portion which forms part of the rotary union.
Thus, the threadings of the wear insert can be reconditioned using
the same techniques as those used for the tubes of the drill
string. The wear insert retains its strength qualities, which are
critical in this region of the string. The cost of reconditioning
the wear insert is optimized compared with known solutions such as
"Data Swivel" or SwivelLink". The overall bulk of the wear insert
is reduced to a minimum.
[0199] Providing the communication device on the valve LKV also
means that this valve can have at least two clamping positions,
namely above the set of antennae and below it, because of the
length of this valve.
[0200] As explained above, the invention is not limited to the case
of top drive drilling, but may also be envisaged in combination
with a profiled stem of the "kelly" type. In this case, the valve
LKV described here could be used as an upper kelly valve while the
profiled stem (kelly), the safety valve (lower kelly valve) and the
lower wear insert (lower saver sub) could each be equipped with end
couplers and a cable electrically connecting said couplers.
[0201] The valve LKV described could also be provided in the form
of a pneumatic valve.
[0202] Although the communication device described above has
numerous advantages when it is integrated into a safety valve of
the kelly valve type, at least some of these advantages are also
enjoyed when the device in question is installed in an axisymmetric
element of the drill string.
[0203] The device described can provide a substantial saving in the
energy consumed by the data transmission operations. This is of
particular importance in the drilling field as the devices in
question, like all of the onboard electrical devices in the drill
string, must be autonomous and as a result are supplied by onboard
batteries. However, exhaustion of a battery may have particularly
disastrous consequences as replacing it requires stopping
production and/or drilling.
[0204] More precisely, the device proposed here offers optimized
management of the energy dedicated to data transmission, since all
of the available power is always attributed to the best performing
antenna or a sub-assembly of the set of antennae, the other
antennae being rendered passive. This is improved still further by
using highly directive antennae, which mean that the antenna or
antennae to be used at a given moment can be selected efficiently.
It should be noted that although at any moment only a portion of
the set of antennae is activated, the proposed device means that
substantially continuous data transmission can be obtained even in
the case of using a single fixed antenna. This transmission may be
carried out at higher rates and with remarkable energy
performances.
[0205] The device proposed can also be used for data transmission
of the TDMA, time division multiple access, type.
* * * * *