METHOD OF ABANDONING A WELL

Abstract

Sealing a well above a barrier or plug, comprising the steps of lowering a first tool on a slickline (21), comprising a plurality of cartridges (26), these cartridges including a plurality of cartridges containing a thermite material at least a first thermite initiator cartridge (70) which includes an activation receiver (73) deploying these cartridges above the barrier or plug transmitting a first wireless signal to first thermite initiator cartridge (70) such that the first thermite initiator cartridge causes a thermite reaction at the said set of the cartridges (26) containing a thermite material.

Claims

1. A method of sealing a well above a barrier or plug, comprising the steps of lowering a first tool on a slickline, comprising a plurality of cartridges, these cartridges including a plurality of cartridges containing a thermite material at least a first thermite initiator cartridge which includes an activation receiver deploying these cartridges above the barrier or plug transmitting a first wireless signal to first thermite initiator cartridge such that the first thermite initiator cartridge causes a thermite reaction at least a first set of the cartridges containing a thermite material.

2. A method of sealing a well according to claim 1 wherein the wireless signal is acoustic.

3. A method of sealing a well according to claim 1 wherein the wireless signal is supplied by a wireless transceiver included on the first tool.

4. A method of sealing a well according to claim 1 wherein the wireless signal is supplied by a wireless transceiver suspended on a second tool lowered on a slickline as a later step.

5. A method of sealing a well according to claim 1 wherein that a second thermite initiator cartridge is included further comprising transmitting a second wireless signal to the second thermite initiator cartridge such that the second thermite initiator cartridge causes a thermite reaction at least a second set of the cartridges containing a thermite material.

6. A method of sealing a well according to claim 5 wherein the second wireless signal to the second thermite initiator cartridge is transmitted or relayed from the first thermite initiator cartridge.

7. A method of sealing a well according to claim 1 wherein a thermite initiator cartridge transmits a wireless confirmation signal after receiving a wireless signal.

8. A method of sealing a well according to claim 1 wherein at least one of the cartridges contains a high temperature thermite material, such that a well casing is severed when the thermite cartridge is activated.

9. A method of sealing a well according to claim 8 wherein a second tool is deployed after the well casing is severed.

10. A method of sealing a well according to claim 1 wherein the plurality of cartridges are deployed in a payload container.

11. A method of sealing a well according to claim 10 wherein the payload container is released from the slickline, and deforms in a coiled shape in the casing.

12. A method of sealing a well according to claim 10 wherein the tool includes a plurality of payload containers joined to each other by flexible connecting members.

13. A method of sealing a well according to claim 1 wherein the plurality of cartridges are released sequentially from the tool.

14. A method of sealing a well according to claim 1 using a tool adapted for use.

Description

[0032] The following is a more detailed description of an embodiment according to the invention by reference to the following drawings in which:

[0033] FIG. 1 is section side view through a well with a casing and a severed production tubing, with a tubing bridge plug, thermite magma, insulation material and weight material, sealing the lower section from an earlier operation.

[0034] FIG. 2 is a similar view to FIG. 1, showing a wireline or slickline tool lowered through the previous tubing, and the tool highlighted by a dotted line box.

[0035] FIG. 3 is an enlarged side view of the tool highlighted above

[0036] FIG. 4 is a similar view to FIG. 3, showing a subsequent stage in the process.

[0037] FIG. 5 is a similar view to FIG. 2, showing a slickline tool which has deposited its payload into the well.

[0038] FIG. 6 is a similar view to FIG. 5, with all the ingredients needed for the operation deployed in cartridges, and a tool deployed on slickline activating the thermite initiators.

[0039] FIG. 7 is a similar view to FIG. 6, after the thermite has been activated and it is severing the casing.

[0040] FIG. 8 is a section side view through a well with the resulting parted tubing by the tool operation in FIG. 7

[0041] FIG. 9 is a side view of another embodiment of the invention being conveyed on a slickline or wireline tool

[0042] FIG. 10 is a subsequent operation to FIG. 9 with hose assembly released from the slickline, and the hose forming a coil at a position of rest inside the casing (casing not shown)

[0043] FIG. 11 is a side view of another embodiment of the invention being conveyed on a slickline or wireline tool

[0044] FIG. 12 is a view of a string of sausages containing the required ingredients released from the deployment tool

[0045] FIG. 13, is a side of the released sausages shown in FIG. 12 coming to rest as a compact pile inside the casing (not shown)

[0046] FIG. 14 is a section side view of the well with an alternative means of communicating with multiple RFID initiating cartridges.

[0047] FIG. 15 is a similar view to FIG. 14, at a subsequent step in the process.

[0048] FIG. 16 is a similar view to FIG. 15, at a subsequent step in the process.

[0049] FIG. 17 is a similar view to FIG. 16, at a subsequent step in the process.

[0050] FIG. 18 is a section side view of the well with another means of communicating with multiple RFID initiating cartridges.

[0051] FIG. 19 is a similar view to FIG. 18, at a subsequent step in the process.

[0052] FIG. 20 is a similar view to FIG. 19, at a subsequent step in the process.

[0053] FIG. 21 is a similar view to FIG. 20, at a subsequent step in the process.

[0054] FIG. 22 is a circuit diagram for an acoustic transmitter/receiver

[0055] Referring to FIGS. 1-8, an objective of this process is to make an access window to the open hole.

[0056] FIG. 1 shows a well where the tubing has been severed using a bridge plug 10, thermal insulation material such as sand or ceramics, reacted thermite 12, a second quantity of thermal insulation material 13 and weight in the form of steel ball bearing 14.

[0057] The next operation will be described in more detail, the objective of which is to sever the next casing outside the one already severed, and to let that casing drop thereby enabling access outside of it.

[0058] This is achieved using a slickline 21 (or wireline or coiled tubing, the term slickline will only be used from now on) to lower the slickline running tool 22 into the well. The running tool clamps 23 to the slickline, extending from the running tool is a thin hollow rod 24, on the end of which is a low temperature alloy end cap 25, mounted on the rod are cartridges 26, which consist of a hermetically sealed chamber 27, with an outer cylindrical wall 28, in inner very small inner cylindrical wall 29, and a top 30, and bottom 31 cap. Inside the chamber, could be any type of dry material or liquid chemicals such as thermite, bismuth, insulation, weighting materials, or instruments or sensors or telemetry such as a sonar Pinger, an acoustic transmitter receiver, or a RFID transmitter receiver, an ignitor to initiate the thermite reaction.

[0059] When the slickline tags the top of the previous plug 32 a heating element is powered up by current supplied by a cable inside the rod 24, the low temperature alloy end plug will melt and then the cartridges will slide down the rod and be deposited on top 33 of the previous plug 32, the empty slickline conveyance means 34 can now return to surface and make a repeat run. The length of the slickline tool is governed by the length of the lubricator at surface and the weight limitation of the slickline. This means of deploying cartridges enables unlimited quantities of the right materials to be deposited into the well, in a controlled way and with total quality control of the process.

[0060] Once the required quantities of low temperature thermite 35, wireless initiator 36, high temperature thermite 37, additional initiators 38, thermal insulation 39 and weighting materials 40 have been installed, a master activation tool 41 is conveyed on the slickline and at the required time, it transmits an acoustic signal to activate the different initiators, and the different initiators transmit back different hand shake to confirm they have received the correct command and have been switched on. The initiators can either be turned on at the same time or different times if a different warm up profile of the thermite is preferred or required. For example, it may be better to ignite the low temperature thermite 36 using a signal A 120 so that it softens the steel casing, which is confirmed by the initiator sending back signal B 121 to the wireless transceiver 41, and then igniting the high temperature thermite 37 using signal C 122 which confirms initiation by returning signal D 123, so that it can more easily sever 42 the softened casing. Ideally this will occur just below the insulation 43. The insulation provides a thermal barrier for the weighting material 44, so the weighting material does not fuse or melt and free fall with the insulation material and the severed casing 45.

[0061] Referring to FIGS. 9 to 13, there is shown other means of conveying long flexible modules of different materials into the well on a mono conductor wireline conveyance system.

[0062] The system consists of a mono conductor wireline 50, attached to which is a grapple connector 51. A shear pin assembly 52 is part of the assembly to enable a clean separation in the event of getting stuck. Termination of the conductor is in a heating element inside a low temperature alloy block 53 which connects the payload 54 to the lower part of the connector 55.

[0063] The payload is a long flexible tube, fitted with a rounded nose piece 56. Inside the flexible tube would be any of the previously described materials that are required for an operation in the well for example those shown in FIGS. 3 and 4.

[0064] When electrical power is applied to the electrical conductor, the heating element is energised and this in turn melts the low temperature alloy which in turn disconnects the payload from the mono conductor running tool.

[0065] The payload comes to rest and coils 57 into a compact form in the casing (not shown) below it. As in the previous system this can be repeated as often as required until the required quantity of material is placed into the well.

[0066] Referring to FIGS. 11 to 13, an alternative arrangement is to have the payload made up made like a string of sausages 64, the connecting members 60 being held tight in the sausage 64′ nearest the release mechanism 61, when the release mechanism is activated the connecting members comes free and allows the sausage containers to separate 62 and when they land in the bottom of the well they fill the space, so forming a bigger diameter and shorter length 63.

[0067] As above, the sausage skin could be plastic, thin steel or composite. Inside the sausage skin would be the desired material as described in FIG. 1-8, and this would be hermetically sealed

[0068] Referring to FIGS. 14 to 17 there is shown an alternative method of initiating the thermite ignitors. RFID (Radio Frequency ID) is now a well-established method of both transmitting and receiving data. An RF module (radio frequency module) is a small electronic device used to transmit and/or receive radio signals between two devices. It is often desirable to communicate with another device wirelessly. For in well applications the wireless communication is best accomplished radio frequency (RF) communication. In well RFID has a proven typical range of between 3-5 meters. In our application, an RFID initiator may be used for the thermite further away from the transmitter than this.

[0069] To overcome this limitation, the initiator is fitted with an RFID receiver/transmitter, connected via a long cable to the cartridge. In practice the deployment process would be as follows;

[0070] The cartridge initiator 70, would be lowered into the well as previously described, it would be adjacent to the running tool 71. At setting depth, an arm 72 would be activated which would deploy a magnet to attach itself to the casing 73, on the magnet will be a RFID transmitter/receiver, and a coiled cable 74 connecting it to the electronics inside the initiator cartridge 70. A solenoid 75 on the running tool would be energised and it would shear a pin 76 on the thin central rod 77 and the cartridges would fall into the bottom of the well. The initiator cartridge 70 would be buried with the rest of the thermite cartridges 78, and connected via the cable 74 to the receiver/transmitter 73.

[0071] When all the required cartridges have been deposited, a tool 79 is deployed on the mono conductor and it transmits 80 to all the RFID devices with their respective unique signals to arm them, they respond confirming they have been armed and then initiate the thermite reaction according to how they have been programmed.

[0072] Referring to FIGS. 18 to 21, there is shown a further embodiment of the invention, showing multiple wireless RFID initiator cartridges 70, which talk to each other in a daisy chain manner exclusively using wireless communication. The signal to the lowest initiator is achieved via multiple

[0073] RFID transmitter/receivers, because the cost is relatively low, they could be in every cartridge, resulting in multiple redundancy for signals in both directions, and also provide a quality assurance, as each cartridge is activated it could transmit that information before being vaporised. The other hermetically sealed cartridges would contain dry materials such as low temperature thermite 84, slow burning thermite 81, high temperature thermite or liquid propellant 82, weighting material 83

[0074] Referring to FIG. 22, there is shown a circuit diagram for a possible embodiment of the one of the acoustic transmitter/receivers for the initiators 38 of the invention. Once all the required tool assembly has been installed into the well, in order to activate the thermite reaction or some similar operation, an acoustic coded signal is transmitted from surface, or from a wireline or slickline deployed tool. A number of features to minimise premature activation are included. Prior to the on-board electronics 100 activating the device, the pressure safety switch 101 interlock has to be activate, and a certain temperature 99 must be achieved, both of these ensure that the device is at a certain depth in the well. Once these conditions have been met, the circuit board 100 goes to ready mode and is receptive to signals. When the circuit receives a command, it is checks for a specific command construction which may include a preamble and postamble (framing bytes), or some other identifier code. If the identifier code is incorrect, it ignores the transmission.

[0075] The assembly may also act to transmit and receive data to and from below it, so it forms a daisy chain.

[0076] First a Ready command is sent, then “arm”, then “fire”. On Fire, the relay 102 latches on, and applies power which comes from 3×4.4 volt 30 amp batteries 103 connected in series to the initiator 104. This all happens to all the acoustically activated switches that are to be initiated together simultaneously.

[0077] The acoustic transmitters/receiver's 105 are specifically tuned to under water performance. When sound travels through medium that has different acoustic impedance, the reflection coefficient R (when energy propagates through mediums) can be calculated as:

[00001]$R={\left(\frac{Z_2-Z_1}{Z_2+Z_1}\right)}^2$

[0078] where Z1, Z2 represent the acoustic impedance value of medium 1 and medium 2. If we like to achieve 100% transmission rate, we like to have R=0 (no energy is reflected)

[0079] In transducers case, the model can be simplified to

1. Piezo ceramics composite (Z1) to air (Z2air, 0.000429 kg/s g/cm3),
2. Piezo ceramics composite (Z1) to water (Z2water, 1.5 kg/s g/cm3)

[0080] When an air transducer is to be used, the goal would be to achieve Z1 as close as to the impedance of air of 0.000429, to minimize the R coefficient. By adding composite, we can achieve Z1 close to 0.00085. In this case, the R coefficient is 10.8%, which means almost 89.2% of the energy is transmitted.

[0081] However, if the same air transducer is used in water, the second medium immediate has 10,000 times of change in acoustic impedance. And therefore, R=99.99%, which means no energy can escape/transmit through the surface. For this reason, the transducer must to be specifically designed for underwater use, rather than employing an air transducer without modification.

TABLE-US-00001 Acoustic impedance Z1 0.00085 Z2 air 0.000429 Z2 water 1.5 R of piezo to air 10.8%  R of piezo to water 100%