Hybrid Telemetry System for Drilling Operations

Abstract

A system of installing a telemetry cable in a drill string, the drill string comprising a plurality of drill pipe sections, the drill string having a drill pipe electrical connector at the bottom of the drill string, an electrical wireline capable of carrying an electric signal is disposed in the drill string, terminating in a lower wireline electrical connector capable of connecting with the lower drill pipe electrical connector, and an upper termination block.

Description

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means before the drillpipe is completed however, the cable must be lowered into the drillpipe string, only to be withdrawn each time a new drillpipe section is added to the drillpipe string.

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 40 ft) 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.

Preparing the cable offsite, terminated and tested to a required length with a small adjustable length section (up to 40 ft) 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 40 ft 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;

FIG. 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.

FIG. 2 shows a similar view to FIG. 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.

FIG. 3, shows in more detail the surface termination hang of sequence.

FIG. 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.

FIG. 5 shows a subsequent step in the hang off sequence to FIG. 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.

FIG. 6 shows a similar view to FIG. 5 with a joint of wired drillpipe added. This allows the rig to drill new hole and supply fast data to the rig floor.

FIG. 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.

FIG. 8 shows a schematic of the side pocket tool joint, incorporating a sensor package to measure annulus measurements such as pressure and temperature.

FIG. 9 shows an alternative embodiment of the hybrid telemetry system shown in FIG. 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.

FIG. 10 shows a further embodiment, 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, the upper assembly comprises a electrical termination and an acoustic transmitter/receiver.

FIG. 11 shows a similar view to FIG. 10 with the retrieval mechanism removed and a new joint of drillpipe added.

FIG. 12 shows side view of the well in the embodiment 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

FIG. 13 show a similar view to FIG. 12 with the drillpipe in a lower position.

FIG. 14 is a similar view to FIG. 13, the drillpipe is at its lowest position before a new joint can be added, the retrieval mechanism fishes the one way anchor and takes it to the top of the drillpipe.

FIG. 15 is a similar view to FIG. 14, the wireline inside the drillpipe can no longer accommodate new drillpipe to be added, so has to be terminated in a sensor sub.

FIG. 16 is a similar view to FIG. 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.

FIG. 17 is a similar view to FIG. 16 with a new joint of drillpipe added.

FIG. 18 is a more detailed side section view of the sensor sub of FIG. 10, with electrical terminations of a lower and upper wireline.

Referring to the figures in more detail, embodiments of the invention will be described.

FIGS. 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. 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 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®. 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.

FIG. 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 FIG. 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 FIG. 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.

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 FIGS. 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 FIGS. 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® 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.

In an alternative embodiment, additional features can be included at the hanging off stage. Referring to FIGS. 10 to 17, the method previously described in relation to FIGS. 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/receiver 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.

So a fast cost effective telemetry path is established from the drilling assembly to surface.

FIG. 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.

Claims

1.-18. (canceled)

19. A system of installing a telemetry cable in a drill string,

the drill string comprising a plurality of drill pipe sections, the drill string having a drillpipe electrical connector at a lower position of the drill string

disposing an electrical wireline capable of carrying an electric signal in the drill string, terminating in a lower wireline electrical connector capable of connecting with the lower drill pipe electrical connector, and an upper termination connector, the length of the electric wireline being greater than the length of the drill string between the lower position of the drill string and the rig floor at the time the electrical wireline is disposed in the drill string

connecting the lower wireline electrical connector and the lower drill pipe electrical connector

the drill string having a drillpipe section electrical connector on inner surface of a drill pipe section at the top of the drill string docking and securing the upper electrical termination connector of the electrical wireline to the drillpipe section electrical connector adding a subsequent drill pipe section to the top of the drill string.

20. A system of installing a telemetry cable according to claim 19, wherein upper electrical termination is secured in the drillpipe section electrical connector by a clamp member lowered through the drill pipe section added to the top of the drill string.

21. A system of installing a telemetry cable according to claim 20, wherein the cable clamp is slidably mounted on the support cable while being lowered

22. A system of installing a telemetry cable according to claim 19, wherein the surplus support cable is cut when a new drill pipe section is added to the drill string.

23. A system of installing a telemetry cable according to claim 19, wherein the drillpipe section electrical connector is then connected to a second length of wireline disposed in the inner bore of the drillpipe.

24. A system of installing a telemetry cable according to claim 19, wherein the drillpipe section electrical connector is connected to a conductor formed in the inner wall of the drillpipe section immediately above the pocket electrical connector.

25. A system of installing a telemetry cable according to claim 19, wherein the lower position of the drill string is the drilling assembly.

26. A system of installing a telemetry cable according to claim 25, wherein the drilling assembly includes sensors connected to the drillpipe electrical connector.

27. A system of installing a telemetry cable according to claim 24, conductor formed in the inner wall of the drillpipe section includes or is connected to sensors attached to the drillpipe section.

28. A system of installing a telemetry cable according to claim 19 wherein a support cable is attached to the electrical wireline to support the weight of the electrical wireline while a new drillpipe section is added to the drillstring.

29. A system of installing a telemetry cable according to claim 19 wherein the surplus cable of the length of the electric wireline is disposed in the substantially helical manner.

30. A system of installing a telemetry cable according to claim 19 wherein the drillpipe section electrical connector is situated in a side pocket on the drill pipe section.

31. A system of installing a telemetry cable according to claim 19 wherein a one way anchor is included at the upper end of the electric wireline.

32. A system of installing a telemetry cable according to claim 31, wherein a fishing tool is used to pull anchor up when a new drillpipe section is added.

33. A system of installing a telemetry cable according to either claim 31, wherein the anchor includes a sensor.

34. A system of installing a telemetry cable according to claim 33, wherein the sensor includes a wireless transmitter.

35. A system of installing a telemetry cable according to claim 19 wherein a sensor included at termination connection of wireline.

36. A system of installing a telemetry cable according to claim 19 wherein the side pocket docking connection includes a sensor.