Note: Descriptions are shown in the official language in which they were submitted.
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Hybrid telemetry system for drilling operations
The present invention relates to a telemetry system, in particular, one
disposed in a drillpipe.
The conventional manner of drilling a borehole comprises lowering a
drill bit into the earth, the drill bit being powered, for instance, by the
rotation of the drillpipe, or by fluids circulating through the drillpipe and
thence back up to the surface through the space between the drillpipe and
the borehole. The drillpipe is made up of sections, new sections being
added periodically at the top of the drillpipe string to allow the drill bit
to
be lowered further.
Much useful data can be garnered from sensors included in the
drillpipe, such as temperature and pressure. To retrieve this information at
the surface requires some form of media to transmit it through. Known
systems include using pressure waves through the circulating mud, and
electromagnetic pulses. Better rates of transfer and less attenuation may be
achieved however by using an electrical conducting element.
The simplest way of installing a conducting cable, or indeed any
line, along the drillpipe string is to wait until drilling has ceased and
lower a
single length down the drillpipe string. Where it is necessary to take
readings from instrumentation means before the drillpipe is completed
however, the cable must be lowered into the drillpipe string, only to be
withdrawn each time a new drillpipe section is added to the drillpipe string.
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One known method comprises a drillpipe incorporating conducting
elements. The conducting elements of adjoining sections of drillpipe are
electrically connected by inductive couplings, Such a system is expensive,
and requires signal boosts. Many telemetry systems rely upon a segmented
cable running through the drillpipe, cable sections being added in order to
allow fresh sections of drillpipe to be added.
Every connection between individual lengths of cable provides a
further opportunity for faults to occur.
The object of the present invention is to provide an apparatus and
method for disposing reliable telemetric equipment in drillpipes and the like
in an efficient manner.
According to the present invention, there is provided a system of
installing a telemetry cable in a drill string as defined in claim 1.
This advantageously allows the maximum length of cable is installed
inside the drillpipe with an electrical wet connector at each end. The cable
may be prepared offsite, terminated and tested to a required length with a
small adjustable length section (up to 40ft) so rapid installation is
possible.
The upper termination of the cable is in a side pocket of a tool joint, the
tool
joint can also include sensors such as pressure and temperature.
As the new hole is drilled, wired drillpipe can then be added, to
communicate from the wireline terminating at the tool joint to surface.
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Preparing the cable offsite, terminated and tested to a required length
with a small adjustable length section (up to 40ft) allows rapid installation.
The upper termination of the cable may be in a side pocket of a tool joint,
the tool joint can also include sensors such as pressure and temperature.
As new hole is drilled, a second wireline may be installed from the
tool joint to the top of the added drillpipe, the wireline is allowed to form
a
loop inside the drillpipe, the upper end of the wireline has a one way
anchor, a electrical termination and acoustic transmitter/receiver.
Inside the riser or BOP stack, whichever is below the first 40ft of rig
floor, a line of acoustic transmitters and recievers may be included, which
listen and transmit to the acoustic transmitter/receiver of the wireline
anchored inside the drill pipe.
As new drillpipe is added the wireline acoustic transmitter is fished
and anchored to the top of the new drillpipe added, this may be repeated
until the wireline can accommodate no new drillpipe. At this time a new
sensor sub is installed in the drillpipe and the wireline electrical
termination
docked into the sensor sub.
A telemetering system will now be described, by way of example,
with reference to the drawings, of which;
Figure 1 shows a section side view of a cased drilled hole, with new
drillpipe and drilling assembly installed, with a side pocket electrical
termination tool joint fitted at the rig floor. Adjacent to the well is a pre-
assembled / terminated wireline of approximately a similar length.
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Figure 2 shows a similar view to figure 1 with the pre-assembled wireline
installed inside the drill pipe, the lower wet connector termination
connected to its mating connector in the drilling assembly, at the surface is
a means of rapidly hanging off a pre-assembled terminated cable.
Figure 3, shows in more detail the surface termination hang of sequence.
Figure 4 shows a subsequent step in the surface hang off sequence, the
cable termination is lowered and installed into the tool joint side pocket
connector, surplus cable is applied to hang from the cable termination and a
cable termination block, the hanging weight of the cable is supported by a
disposable support line.
Figure 5 shows a subsequent step in the hang off sequence to figure 4, while
the hanging weight of the cable inside the drillpipe is still supported a
sliding support is lowered down the cable and comes to rest on top of the
upper electrical termination. It is then locked to the remaining supporting
cable inside the drillpipe. The surplus support cable is then cut and removed
so that new drillpipe can be added.
Figure 6 shows a similar view to figure 5 with a joint of wired drillpipe
added. This allows the rig to drill new hole and supply fast data to the rig
floor.
Figure 7 shows an overview of the hybrid telemetry system, with internal
wireline from the drilling assembly to the side pocket tool joint and then
wired drillpipe back to surface.
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Figure 8 shows a schematic of the side pocket tool joint, incorporating a
sensor package to measure annulus measurements such as pressure and
temperature.
Figure 9 shows an alternative embodiment of the hybrid telemetry system
shown in figure 7, with two sets of internal wireline being used, one from
the drilling assembly to the side pocket tool joint, and then a further
section
of internal wireline, this being connected to a wired drillpipe back to
surface.
Figure 10 shows a further embodimeny, with a second wireline installed in
a second wet connector of the sensor sub, and the wireline forming a U
loop, its upper end has a one way anchor which holds the upper assembly
where it is pulled up to by a retrieval mechanism, theupper assembly
comprises a electrical termination and an acoustic transmitter / receiver.
Figure 11 shows a similar view to figure 10 with the retrieval mechanism
removed and a new joint of dillpipe added.
Figure 12 shows side view of the well in the embodimeny of figure from
surface to total depth, at surface it shows the acoustic transmitter inside
the
drillpipe talking to a series of acoustic transmitters/recievers inside the
riser
or BOP stack
Figure 13 shoiw a similar view to figure 12 with the drillpipe in a lower
position.
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Figure 14 is a similar view to figure 13, the drillpipe is at its lowest
position
before a new joint can be added, the retrival mechanism fishes the one way
anchor and takes it to the top of the drillpipe.
Figure 15 is a similar view to figure 14, the wireline inside the drillpipe
can
no longer accommodate new drillpipe to be added, so has to be terminated
in a sensor sub.
Figure 16 is a similar view to figure 15 with a new wireline added and
docked into the sensor sub to link all the wirelines to its upper termination.
Its upper termination includes the previously mentioned electrical
termination, anchor assembly and acoustic transmitter/receiver.
Figure 17 is a similar view to figure 16 with a new joint of drillpipe added.
Figure 18 is a more detailed side section view of the sensor sub of figure 10,
with electical terminations of a lower and upper wireline.
Referring to the figures in more detail, embodiments of the invention will
be described.
Figures 1 to 7 there is shown a borehole 1, lined by a casing 2 which
has been cemented in place, a rig floor is shown as 3. A drilling assembly 4
consisting of a directional drilling system 5, steering and sensor package 6
is lowered into the well on drillpipe 7, when it has reached the bottom of
the well 8 a side pocket tool joint 9 is installed into the drillstring, the
total
length of the drill string would be known to within a +/- 5 to 10 feet.
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A off-site prepared wireline 10 with upper and lower terminations is
lowered into the inside of the drillpipe, its lower end has a wet electrical
connector termination 11, this lands and docks into a mating termination on
top of the telemetry module of the sensor package 6. At surface, surplus
cable has to be accommodated into the drillpipe. This is achieved as
follows; the wireline is terminated into a termination block 12 at a known
shorter length of the drillpipe. The hanging weight of the wireline is
supported from the termination block 12 by a suitable strong cable 13. The
wireline 15 is first slacked off, so that it rests in a helical path 15' on
the
inside of the drillpipe. A flexible lighter gauge Kevlar braided cable 14
continues the wireline 15' signal transmission capability to a upper
electrical termination 16. The upper termination can be lowered and docked
into an internal side pocket electrical connector 17, the surplus cable 13 is
allowed to hang from the docked connector 18 forming a U shape to the
termination block 12. A cable clamp and support 19, is lowered down the
support cable 13 and locates into the top of the cable termination 16, and
locks the two items 16, 19 into the side pocket. The cable clamp 19 locks
onto the support cable 13 at 20. The remaining or disposable section of
support cable 22 can be removed by cutting at 21.
Allowing the surplus cable of the wireline 15' to adopt a helical shape
causes the wireline 15' to abut against the inner surface of the drillpipe
sections making up the drillstring. The friction of this abutment supports
the weight of the wireline, meaning that less strain is placed on the wireline
during installation.
Now new drillpipe 23 can be added to drill new hole, the new drillpipe
being wired drillpipe having conductors within the drillpipe section walls
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and electrical connectors at the joints of each drillpipe section, so that a
conductive path is established along multiple drillpipe sections.
Additionally, these wired drillpipe sections can have sensors within the
drillpipe to gather telemetry which is them transmitted through the
conductive path. This is well understood equipment and available
commercially as Intellipipe(R). In this way, a fast cost effective telemetry
path is established from the drilling assembly to surface, but avoiding the
cost of using wired drillpipe sections over the entire length of the drillpipe
string.
Figure 8 shows a side pocket docking port with annular sensor capability.
The electrical termination of the wireline goes to an inductive coil 30,
which transmits the signal across the tool joint via contactless telemetry to
a
coil 31 in the upper tool joint. A sensor package 32 could measure annular
parameters such as pressure, temperature etc., and these too could be
processed and transmitted back to surface, providing vital information of
what is happening in the wellbore annulus.
Referring to figure 9, the hybrid telemetry system may use more than one
section of internal wireline, allowing greater lengths of conventional, non-
wired drillpipe section to be used. Here, a first wireline 15' and docked
connector 28 is disposed between the drilling assembly and an internal side
pocket 27. A clamp connector 30 is then deployed in the same manner as
the clamp 20 shown in figure 7. In this embodiment however, the clamp
connector 30 includes a second wireline 25 extending from it, and the
clamp connector 30 makes an electric connection with the docked connector
28.
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Further conventional drillpipe sections can then be added, with the wireline
25 suspended by a support line (not shown) and threaded through new
drillpipe sections as they are added in a similar manner to that described in
relation to figures 1 to 7. The second wireline 25 is then connected to a
docking connector 38 with a clamp 39 in exactly the same manner as
described in to figures 1 to 7, the docking connector 38 having an electrical
connection to a conductor running through the drillpipe section added above
this, such as drillpipe sections of the Intellipipe (R) design.
Lengths of conventional drillpipe sections and lengths of wired drillpipe
sections can in this way be alternated depending on where the operators
what wired drillpipe telemetry, so that the cost of using the wired drillpipe
sections is minimised and reliability and speed of installation is increased.
The upper termination block of the wireline has been described as docking
with a side pocket connector, where a side pocket is usually considered to
be a cavity in a drillpipe section communicating with the inner bore of the
drillstring, but which does not occlude the inner bore. However, though
less ideal, the drill pipe connector could also secured to the drill pipe in
some manner so that the connection of the termination block of the
electrical wireline can be made to the connector attached to the drill pipe
section (whether as a wired drill pipe section, or in order to continue the
drill pipe telemetry connection in a 'daisy chain' manner). The drill pipe
connector could for example be secured to the inner surface of the drill
pipe, or could comprise a spider that spans the throughbore of the drill pipe
section. It will though be accessible from the rig floor as the drillpipe
section is added so the connection between the wireline and the drillpipe
electrical connector can be made.
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In an alternative embodiment, additional features can be included at the
hanging off stage. Referring to figures 10 to 17, the method previously
described in relation to figures 1 to 5 is carried out. Then a new wireline
with a side pocket electrical connector 30 is disposed to become a new
extension of the wireline end termination 18 hanging off in the electrical
connector 17. the upper end of this cable has a one way anchor 31, below
which is connected the wireline electrical termination 32. Just before a new
section of drill pipe 33 is added, a fishing tool 34 is lowered inside the
drillpipe and pulls the one way anchor to around the rig floor level 35. It is
disengaged and the drillpipe 33 is connected to the drillpipe in the slips,
and
drilling ahead can commence. As the drillpipe goes below the rig floor, the
acoustic transmitter / reciver 36 is continuously transmitting to an array of
acoustic transmitter / recievers 37 either mounted in the riser or the BOP
stack. Many joints of drillpipe can be added, because there is an excess of
extra wireline 38 forming a U shape inside the drillpipe. As the top of the
drillpipe reaches the rig floor, the fishing tool again goes inside the
drillpipe
and fishes the one way anchor 39 to just below the rig floor. When there is
insufficient wireline to add new drillpipe, a sensor sub 40 and wire
termination is added. This allows the last wireline 41 to be terminated and a
new wireline 42 to be added with a termination 43 into the sensor sub and a
one way anchor and transmitter 44 at its upper end. The sensor sub could
measure external pressure and temperature and be useful for both well
control and gather other well data. The wireline is in effect daisy chained
together in controlled lengths and joined together at each sensor sub using
electrical connectors.
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So a fast cost effective telemetry path is established from the drilling
assembly to surface.
Figure 18 shows a side pocket docking port with annular sensor capability.
The wireline electrical termination 50 of the wireline plugs into a matching
electrical connector 51 this goes to a sensor module 52 which converts the
sensor signals to a telemetry signal and transmits that onto the wireline. A
second connector 53, allows a new wireline 54 to be added to extend the
wireline inside the drillpipe and its end termination 55 plugs into the
matching terminator 53 in the sensor sub. The sensor package 52 could
measure annular parameters such as pressure, temperature etc, and these too
could be processed and transmitted back to surface, providing vital
information of what is happening in the wellbore annulus.
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