GB2337780A

GB2337780A - Surface assembled spoolable coiled tubing strings

Info

Publication number: GB2337780A
Application number: GB9912588A
Authority: GB
Inventors: Timothy Kean Jackson; Eugene D Bespalov; David H Neuroth; Earl B Brookbank; Paulo Tubel
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 1998-05-29
Filing date: 1999-05-28
Publication date: 1999-12-01
Anticipated expiration: 2019-05-28
Also published as: NO992587D0; GB9912588D0; GB2337780B; NO321960B1; NO992587L

Abstract

A method of making a spoolable coiled tubing string 110 prior to transporting said string 110 to a well site 104 is disclosed, comprising: providing a coiled tubing 111 of sufficient length to reach a desired depth in a wellbore 102, said coiled tubing 111 having an upper end 111b and a lower end 111a ; attaching a lower adapter 430 at said lower end 111a of said coiled tubing prior transporting said coiled tubing string 110 to the well site 104, said lower adapter 430 including a first pressure barrier 432 between said wellbore 102 and inside of said coiled tubing 111, said lower adapter 430 also adapted for attachment to a downhole device 460; and attaching an upper adapter to said upper end 111 b of the coiled tubing 111 prior to transporting said coiled tubing string 110 to the well site 104, said upper adapter adapted for connection to a device at the well head. The coiled tubing string 110 is preferably tested at the assembly site and transported to the well bore 102 on reels. The coiled tubing string 110 is inserted and retrieved from the wellbore 102 utilizing an adjustable opening injector head system. Completion strings assembled at the surface 105 to include sensors and one or more controlled devices which may have upsets in the coiled tubing are also disclosed. These strings may include conductors and hydraulic lines in the coiled tubing, which provide power and data communication between the sensors, devices and surface instrumentation.

Description

2337780 1 TITLE: COILED TUBING STIRINGS AND INSTALLATION METHODS 2 3 4

Field of the Invention

6 7 This invention relates generally to completion and production strings and 8 more particularly to spooled coiled tubing strings having devices and sensors 9 assembled In the string and tested at the surface prior to their deployment in the wellbores.

BACKGROUND OF THE INVENTION

12 2.

13 Background of the Art

To obtain hydrocarbons from the earth subsurface formations 15 ("reservoirs") wellbores or boreholes are drilled into the reservoir. The wellbore 16 is completed to flow the hydrocarbons from the reservoirs to the surface 17 through the wellbore. To complete the wellbore, a casing is typically placed in js the wellbore. The casing and the wellbore are perforated at desired depths to 19 allow the hydrocarbons to flow from the reservoir to the wellbore. Devices 20 such as sliding sleeves, packers, anchors, fluid flow control devices and a 21 variety of sensors are installed in or on the casing. Such wellbores' are referred 22 to as the "cased holes." For the purpose of this invention, the casing with the 1 1 1 1 1 associated devices Is referred to as the completion string. Additional tubings, 2 flow control devices and sensors are sometimes installed in the casing to 3 control the fluid flow to the surface. Such tubings along with the associated 4 devices are referred to as the 'production Wingsg. An electric submersible pump (ESP) is Installed in the wellbore to aid the lifting of the hydrocarbons to 6 the surface when the downhole pressure is not sufficient to provide lift to the 7 f luid. Alternatively, ' the well, at least partially, may be completed without the 8 casing by installing the desired devices and sensors in the uncased or open 9 hole. Such completions are referred to as the "open hoW completions. A string may also be configured to perform the functions of both the completion 11 string and the production string.' 12 13 14 Coiled tubing is often used as the tubing for the completion andlor production strings. The coiled tubing is transported to the well site on spools or reels and the devices that cause upsets in the tubing are integrated into the coiled tubing at the well site as it is deployed into the wellbore. Spooled coiled 16 17 tubing strings with integrated devices have been proposed. Such strings can 18 be assembled at the factory and deployed in the wellbore without additional 19 assembly at the well site. However, the prior art proposed spooled coiled tubing strings require that there be no "upsets' of the outer diameter of the 21 coiled tubing, i.e., the devices integrated into the coiled tubing must be placed 22 inside the coiled tubing or that their outer surfaces be flush with the outer 2 1 diameter of the coiled tubing. Such limitations have been considered 2 necessary by the prior art because coiled tubings are inserted and retrieved 3 from the wellbores by injector heads, which are typically designed to handle 4 coiled tubings of uniform outer dimensions. In many oilfield applications, it is 5 not feasible or practical to avoid upsets because the gap between the coiled 6 tubing and the borehole wall or the casing may be too large for efficient use of 7 certain devices such as packers and.anchors or because of other design and 8 safety considerations. Also. firriffing the outer diameter of the devices to the 9 coiled tubing diameter will require designing new devices.

Additionally, the prior art coiled tubing strings do not include sensors required for determining the operation and health (condition) of the various devices and sensors in the string, or controllers downhole andlor at the surface for operating the downhole devices, for monitoring production from the wellbore and for monitoring the wellbore and reservoir conditions during the life of the wellbore. The prior art spooled coiled tubing strings do not provide mechanisms for testing the devices and sensors from an end of the tubing at the surface before the deployment of the string in the wellbore. Completely assembling the string with desired devices and sensors and having mechanisms to test the operations of the devices and the sensors at the factory prior to the deployment of the string in the wellbore can substantially increase the quality and reliability of the such strings and reduce the

3 deployment and retrieval time.

3 A specific type of coiled tubing, referred to "electro-coiled-tubing" 4 (ECT), contains high power cable, data communication lines or links and 5 hydraulic lines inside the coiled tubing. An ECT is attached to a downhole 6 electrical submersible pump (ESP) with a lower coiled tubing adapter and to the 7 wellhead with an upper coiled tubing adapter. These adapters are installed on 8 the coiled tubing at the well site, typically at the work area below the tubing 9 injector. The lower adapter is assembled on the ECT immediately after the ESP 10 and related equipment has been prepared and hung off in the well. 11 Commercially available adapters are relatively complex devices. They contain 12 fairly complex electrical penetrators (also sometimes referred to as "feed 13 through") along with associated cable connectors which carry electrical power 14 form the ESP power cable across a pressure transition region into the motor 15 and seal section. During deployment of the ECT in the well, if the ECT is not 16 filled with a fluid, it creates a large differential pressure between the wellbore 17 and the inside of the ECT. The penetrator In the lower adapter isolates the 18 Inside of the ECT from the wellbore pressure. The lower adapter also includes 19 passages for hydraulic lines and instrument lines and a shear subassembly that 20 can be broken In case the system gets stuck in the well. Installing. a lower 21 adapter on the ECT at the well site is a relatively complex and time consuming 22 process. Sophisticated electronic devices, sensors and fiber optic cables and 4 1 devices are now being used or have been proposed for use in electro- coiled2 tubings. It is highly desirable to assemble and fully test such ECTS prior to 3 transporting them to the welisite. 4 8 After attaching the lower adapter, the ECT carrying the ESP and 6 associated equipment is run into the well with the tubing injector to the desired 7 location (depth). The upper coiled tubing adapter is then attached to the ECT, As with the lower adapter, the upper adapter also contains an electrical 9 penetrator, various connectors, hydraulic lines and conductors or wires. The 10 upper adapter is then attached to a tubing hanger which is then lowered into 11 the wellhead equipment to support the ECT in the well. Assembly of the upper 12 13 14 adapter also is very complex and time consuming. Completely testing the ECT after Installing the upper and lower adapters at the well site is not feasible or possible. Thus, it is desirable to install and test all such devices at the factory, which is a relatively clean environment and is conducive to performing rigorous 16 testing of the assembled systems.

17 18 The present invention provides spoofed coiled tubing strings which 19 include the desired devices and sensors and wherein the devices may cause 20 upsets in the coiled tubing. The string is assembled and tested at the factory 21 and transported to the well site on spools and deployed into the wellbore by an 22 injector head system designed to accommodate upsets in the tubing strings.

1 The strings of the present invention may be completion strings, production 2 strings and may be deployed in open or cased holes. This invention also 3 provides methods for installing and testing an ECT at the surface prior to 4 transporting them to the well site. The ESP can be installed at the factory or 5 at the well site.

SUMMARY OF THE INVENTION

This invention provides oilfield coiled tubing production and completion strings (production andlor completion strings) which are assembled at the surface to include sensors and one or more controlled devices that can be tested from a remote end of the string. The devices may cause upsets in the coiled tubing. The strings preferably include date communication, power links and hydraulic lines along the coiled tubing. Conductors in the tubing provide power and data communication between the sensors, devices and surface 16 instrumentation. Assembled coiled tubing strings maybe fully listed and 17 certified at the assembly site and are transported to the well she on reels. The 18 -coiled tubing strings are inserted and retrieved from the wellbores utilizing 19 adjustable-opening injector heads. Preferably two injector beads are used to 20 accommodate for the upsets and to move the coiled tubing.

21 22 In one embodiment, the string includes at least one flow control device 6 1 for regulating the flow of the production fluids from the well, a controller 2 associated with the flow control device for controlling the operation of the flow 3 control device and the flow of fluid therethrough, a first set of sensors 4 monitoring downhole production parameters adjacent the flow control device, and a second set of sensors along the coiled tubing and spaced from the flow 6 control device provides measurements relating to wellbore parameters. Some 7 of these sensors may monitor formation parameters such as resistivity, water 8 saturation etc. The sensors may include pressure sensors, temperature 9 sensors, vibration sensors, accelerometers, sensors for determining the fluid constituents, sensors for monitoring operating conditions of downhole devices 11 and formation evaluation sensors. A controller receives the information from 12 the sensors and in response thereto and other parameters or instructions 13 provides control signals to the control device. The controller is preferably 14 located at least in part downhole. The sensors may be of any type including fiber optic sensors. The communication link may be a conventional bus or fiber 16 optic link extending from the surface to the devices and sensors in the string.

17 A hydraulic line run along the coiled tubing may be used to activate 18 hydraulically-operated devices.

19 In an alternative embodiment, the coiled tubing string is a completion 21 string that Includes sensors and a controlled device which is available for 22 testing from the remote end of the string before deployment of the string in the 7 1 1 wellbore. A flow control device on the coiled tubing regulates the produced 2 fluids from the well. A controller associated with the flow control device 3 controls the operation of the device and the flow of fluid therethrough. A first 4 set of sensors monitors the downhole production parameters adjacent the flow 5 control device. The surface- operated devices in the string are activated or set E; after the deployment of the string in the wellbore.

7 This invention also provides a method of making an clectro-coiled-tubing 9 ('uECT") carrying a high power line. A lower adapter having a pressure penetrator or barrier Is attached to the lower end of the coiled tubing. Any 11 required sensors, hydraulic lines, power lines and data lines are included in the 12 coiled tubing prior to attaching the lower adapter. An upper adapter is 13 attached to the upper end of the coiled tubing. A tubing hanger and an 14 electrical connector are attached uphole of the upper adapter. A second pressure penetrator is included in the upper adapter or at a suitable place 16 proximate the upper end of the coiled tubing. This provides a coiled tubing 17 string wherein the upper and lower pressure penetrators are installed at the 18 factory and fully tested prior to transportation of the ECT to the well site. The 19 upper and lower pressure penetrators provide effective pressure barriers at both ends of the string. The string can then be inserted into the wellbore 21 without taking extra safety measures with respect to pressure differential 22 between the wellbore and the coiled tubing inside. The ESP and associated 8 1 equipment or any other desired equipment may be assembled at the factory or 2 at the well site. 3 4 5 BRIEF DESCRIPTION OF THE DRAWINGS

For understanding of the present invention, reference should be made to 7 the following detailed descfiption of the preferred embodiment, taken in conjunction with the accompanying drawings, In which like elements have been given like numerals, wherein:

8 9 10 11 12 13 14 is 16 17 Figure 3 Is a schematic diagram of the spooled coiled tubing string being 18 deployed into a wellbore with two variable width injector heads according to 19 one embodiment of the present invention. 20 21 22 Figure 1 Is a schematic illustration of an exemplary coiled tubing string made according to the present invention and deployed in a wellbore.

Figure 2 is a schematic illustration of a spoolable coiled tubing production string placed in a wellbore.

Figure 4 is a schematic illustration of an ESP and associated equipment deployed in a wellbore with an ECT made according to the present invention.

9 Y' 1 1 2 Figure 5 shows a cross-sectional view of a lower adapter according to 3 one embodiment of the present invention.

4 Figure 6 shows a cross-sectional view of a connector that connects to 6 the lower end of the adapter of Figure 5 and an ESP.

7 8 9 Figure 1 is a schematic illustration of an exemplary wellbore system 100 11 wherein a coiled tubing completion string 110 made according to one 12 embodiment of the present invention Is deployed in an open hole 102. For 13 simplicity and for ease of explanation, the term wellbore or borehole used 14 herein refers to either the open hole or cased hole. The string 110 is assembled at the factory and transported to the well site 104 by conventional methods. After the wellbore 102 has been drilled to a desired depth, the string is inserted or deployed in the wellbore 102 by any suitable method. A preferred injector head system for the deployment and retrieval of the spooled coiled tubing strings of the present invention is described below with reference to Figure 3, The various desired devices and sensors in the string 110 are placed or integrated into the string 110 at predetermined locations so that when the string 110 is deployed in the well bore 102, the devices and sensors DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

1 in the string 110 will be located at their desired depths in the wellbore 102.

2 3 In the example of Figure 1, the string 110 includes a coiled tubing 111 4 having at its bottom end 111a a flow control device 120 that allows the formation fluid 107 from the production zone or reservoir 106 to flow into the tubing 111. The flow control device 120 may be a screen, an Instrumented screen, an electrically-operated andlor remotely controlled slotted sleeve or any other suitable device. An internal fluid flow control valve 124 in the coiled 9 tubing 111 controls the fluid flow through the tubing 111 to the surface 105.

One or more packers, such as packers 122 and 126, are installed at appropriate locations in the string 110. For the purposes of illustration, the 11 12 packer 122 is shown in its initial or unextended position while the packer 126 13 is shown In its fully extended or deployed position in the wellbore 102. The 14 packers 122 and 126 may be flush with the coiled tubing 111 or on the outside of the coiled tubing 111 that causes upsets in the tubing. An annular 16 safety valve 128 is provided on the tubing 111 to prevent blow outs. Other 17 desired devices, generally referred herein by numeral 130 may be located in 18 the string 110 at desired locations. The packers 122 and 126, annular safety 19 valve 128 and any of the devices 130 may cause upsets in the coiled tubing 111 as shown at 122a for the packer 122. The outer dimension 1 22a of the 21 packer 122 is greater than the diameter of the coiled tubing 111. It should be 22 noted that spooled strings of the present invention are not limited to the 11 1 devices described herein. Any suitable device or sensor may be utilized in such 2 strings. Such other devices may include, without limitation, anchors, control 3 valves, flow diverters, seal assemblies electrically submersible pumps (ESP) 4 and any other spoolable device. 5 6 The devices 120, 122, 126 and 130 may be hydraulicallY-Operated, electrically-operated,, electrically-actuated and hydraulically operated, or mechanically operated. For example, as noted above, the flow restriction 9 device 120 may be a remotely-controlled electricallyoperated device wherein fluid flow from the formation 107 to the wellbore 102 can be adjusted from 11 the surface or by a downhole controller. The screen 120 may be instrumented 12 to operate in any other manner. The packers 122 and 126 may be 13 hydraulically-operated and may be set by the supply of fluid under pressure 14 from the surface 105 or activated from the surface and set by the hydrostatic pressure of the wellbore 102. the devices 130 may also include solenoid- 16 controlled devices to regulate or modulate the fluid flow through the string 17 110.

18 19 20 21 22 Still referring to Figure 1, sensors 1 50a-11 50m in the string 110 monitor the downhole prod uction parameters adjacent the flow control device 124. These sensors include flow rate sensors or flow meters, pressure sensors, and temperature sensors. Sensors 152a-11 52n placed at suitable locations along 12 i 1 the coiled tubing 111 are used to determine the operating conditions of 2 downhole devices, monitor conditions or health of downhole devices, monitor 3 production parameters, determine formation parameters and obtain information 4 to determine the condition of the reservoir, perform reservoir modeling, update seismic graphs and monitor remedial or workover operations. Such sensors 6 may include pressure sensors, temperature sensors, vibration sensors and 7 accelerometers. At least some of these sensors may monitor formation a parameters or parameters present outside the borehole 102 such as the 9 resistivity of the formation, porosity, permeability, rock matrix composition, density, bed boundaries etc. Sensors for determining the water content and 11 other constituents of the formation fluid may also be used. Such sensors are 12 known in the art and are thus not described in detail. Also, the present 13 invention is particularly suitable for the use of fiber optic sensors distributed 14 along the string 110. Fiber optic sensors are small in size and can be configured to provide measurements that include pressure, temperature, 16 vibration and flow.

17 18 19 20 21 22 A processor or controller 140 at the surface 105 communicates with the downhole devices such as 124 and 130 and sensors 150a-150m and 152a-152n via a two-way communication link 160. As an alternative or in addition to the processor 140, a processor 140a may be deployed downhole to process signals from the various sensors and to control the devices in the 13 1 string 110. The communication link 160 may be Installed along the inside or 2 outside of the coiled tubing 111. The communication link 160 may contain 3 one or more conductors andlor fiber optic links. Alternatively, a wireless 4 communication link, such as electromagnetic telemetry or acoustic telemetry may be utilized with the appropriate transmitters and receivers located in the 6 string 110 andlor at the surface 105. A hydraulic line 162 is preferably run 7 along the tubing 111 for supplying fluid under pressure from a surface source 8 to hydraulically-operated devices. The communication link 160 and the 9 hydraulic line 162 are accessible at the coiled tubing remote end 11 lb at the surface, which allows testing of the devices 124 and sensors 150a-150m and 11 152a-152n atthe surface prior to transporting the string 110 to the well site 12 and then operating such devices after the deployment of the string 110 in 13 wellbore 102. After the string 110 has been installed in the wellbor6 102, the 14 hydraulically-operated downhole devices are activated by supplying fluid under pressure from a source at the surface (not shown) via the hydraulic line 162.

16 Electrically-operated devices are controlled via] the link 160.

17 is 19 21 22 The information or signals from the various sensors 150a-150m and 152a- 152n are received by the controller 140 andlor 140a. The controller 140 andlor 140a which include programs or models and associated memory and data storage devices (not shown), manipulates or processes data from the sensors 150a-150m and 150a-150n and provides control signals to the 14 1 downhole devices such as the flow control device 124, thereby controlling the 2 operation of such devices. The controls may be accomplished via conventional 3 methods or fiber optics. The controllers 140 andlor 140a also process 4 downhole data during the life of the wellbore. As noted above, data from the s pressure sensors, temperature sensors and vibration sensors may also be E; utibed for secondary recovery operations, such as fracturing, steam injection, 7 wellbore cleaning, reservoir monitoring, etc. Accelerometers or vibration 8 sensors may be used to perform seismic surveys which are then used to 9 update existing seismic maps. 10 11 It should be obvious that Figure 1 is ordy an example of the coiled tubing string with exemplary devices. Any spoolable device may be used in the string 13 110. Such devices may also include safety valves, gas lift devices landing nipples, packer, anchors, pump out plugs, sleeves, electrical submersible pumps (ESPs), robotics devices, etc. The specific devices and sensors utilized will depend upon the particular application. It should also be noted that the 17 spooled coiled tubing string 110 may be designed for both open holes and 18 cased holes.

19 F1gure 2 shows an example of spooled production coiled tubing strings 21 Installed in a multilateral wellbore system 200. The system 200 includes a 22 main wellbore 212 and lateral wellbores 214 and 216. The lateral wellbore 1 214 has a perforated zone 220 that allows the formation fluid to flow into the 2 lateral wellbore 214 and into the main wellbore 212. The lateral wellbore 216 3 has installed a coiled tubing string 236 that contains slotted liners 217a-217c 4 and external easing packers (ECP's) 219a-219c. The packers 219a-219e are activated from the surface after the string 236 has been placed in the wellbore 6 216 in the manner described above with reference to Figure 1. The formation 7 fluid enters the lateral wellbore 216 via the liners 217a-217c and flows into 8 the main wellbore 212.

9 A spoolable coiled tubing production string 232 installed in the main 11 wellbore includes an inflow control device 242, which may be wire- wrapped 12 device, a slotted liner, a downhole or remotely-operated sliding sleeve, an 13 instrumented screen or any other suitable device. A packer 244 isolates the 14 production zone from the remaining string 232. Isolation packers 246a- 246c are placed spaced apart at suitable locations on coiled tubing string 232. The 16 packers 246a-246c may be hydraulically-operated, either by the supply of the 17 pressurized fluid from the surface, as described above or by the hydrostatic 19 pressure that is activated in any manner known in the art. Flow control device 19 248a controls the fluid flow from the inflow control device 242 into the main wellbore while the device 248b controls the flow to the surface. Additional 21 flow control devices may be installed in the string 232 or in the lateral 22 wellbores. Flow meters 252a and 252b provide the flow rate at their 16 1 respective locations in the tubing 232. Pressure and temperature sensors 260 2 are preferably distributively located in the tubing 232. Additional sensors, 3 commonly referred herein by numeral 262 are Installed to provide information ab parameters outside the wellbore 212. Such parameters may include resistivity of the formation, contents and composition of the formation fluids, etc. Other devices, such as annular safety valves 266, swab valves 268 and tubing mounted safety valves 270 are installed In the tubing 232. Other devices, generally denoted herein by numeral 280 may be installed at suitable locations in the string. Such devices may include an electrical submersible pump (ESP) for lifting fluids to the surface 105 and other devices deemed 11 useful for the efficient operation of the well andlor for the management of the reservoir.

A conduit 282 is used to provide hydraulic fluid to the downhole devices and to run conductors along the tubing 232. Separate conduits or arrangements may be utilized for the supply of the pressurized fluid from the surface and to run communication and power links. A processorlcontroller 140 at the surface preferably controls the operation of the downhcle devices and utilized the Information from the various sensors described above. One or more control units or processors may also be placed at a suitable locations in the coiled tubing string 232 to perform some or all of the functions of the processor/controller 140.

17 1 2 Figure 3 is a schematic diagram showing the deployment of a spooled 3 coiled tubing string 322 made according to the present invention into a 4 wellbore utilizing adjustable opening injector heads. The coiled tubing string 322 containing t he desired devices and sensors is preferably spooled on a large diameter reel 340 and transported to the rig site or well site 305. The string 322 is moved from the reel 340 to the rig 310 by a first injector 345 which is preferably installed near or on the reel 340. A second injector 320 is placed on the rig 310 above the wellhead equipment generally denoted herein by numeral 3 1 17. The tubing 322 passes over a gooseneck 325 and into the wellbore via an opening 321 of the injector head 320. The reel injector 345 can maintain 12 an arch of radius R of the tubing 322 that Is sufficient to eliminate the use of 13 the tubing guidance member or gooseneck 325 during normal operations, 14 which reduces the stress on the tubing 322. The opening 346 of the reel injector 345 and opening 321 of the main injector 320 can be adjusted while 16 these injector heads move the tubing 322 to accommodate for any upsets In 17 the tubing string 322 and to adjust the gripping force applied on the tubing.

18 Thus, with this system it is relatively easy to move the tubing 322 in and out 19 of the wellbore to accommodate for any upsets in the tubing 322.

21 22 8 9 10 The injector heads 320 and 345 are preferably hydraulically-operated. A control unit 370 controls electrically-operated valves 324 to control of the is 1 pressurized fluid from the hydraulic power unit 360 to the injector heads 320 2 and 345. Sensors 316, 319, 327, 347, and 362 and other desired sensors 3 appropriately installed in the system of Figure 3 provide information to the 4 control unit 370 to independently control the width of the openings 321 and 5 346, the speed of the tubing 32-2 through each of the injectors 320 and 345 6 and the force applied by such injectors onto the tubing 322. This allows for 7 independent adjustment of the head openings to accommodate any upsets in 8 the tubing 322 and the movement of the tubing into or out of the wellbore 102 9 from a remote location without any manual operations at the rig. The two 10 injector heads ensure adequate gripping force on the tubing 322 at all times 11 and make it unnecessary to assemble coiled tubing strings without any upsets. 12 13 14 is 16 17 18 19 20 21 Figure 4'is a schematic illustration of an ESP and associated equipment deployed in a wellbore 435 having a easing 402 and a casing liner 404 with an ECT made according to the present invention. The ECT 410 is made according to a known method in the art. It preferably Includes a high power cable 412 for carrying power to the ESP 460 and its associated equipment such as a motor 422, one or more hydraulic lines 414 and any other data and power carrying conduits 416, such as wires and fiber optic cables. A lower coiled tubing adapter 430 is assembled on the ECT 410 at the factory or at any suitable place other than at the well site. A suitable adapter is described in 22 detail in reference to Figures 5 and 6. The lower adapter includes a pressure 19 1 penetrator or barrier 432 which isolates the wellbore hydrostaticpressure in 2 the well 435 from the inside 411 of the ECT 410. The adapter described 3 hereafter is installed on the ECT at the point of manufacturing and the 4 assembled ECT is fully tested prior to transportation to the wellsite.

6 Welding the adapter to the coiled ECT 410 can provide stronger and 7 more reliable connections compared to the presently used methods. Since, in 8 the prior art methods, the adapters are connected at the well site, welding

9 cannot be used due to obvious safety reasons. In the present invention, since the adapter 430 is connected to the ECT 410 at the assembly plant prior to 11 transporting it to the well site, adapter 430 may be welded to the ECT 410 at 12 the connection point 434. The weld 434 is tested by any non- destructive 13 testing method, such as x-ray or pressure test, to ensure the integrity of the 14 weld 434. Welded connections are also much smaller than the conventional slips, elastorner seals etc. Smaller connections offer great advantages in 16 reducing the end complexity of subsea trees 450 and other wellhead 17 equipment. An upper coiled tubing adapter 440 is then connected to the upper 18 end 414 of the ECT 410, by conventional methods or by a weld 444. The 19 upper adapter includes a second pressure or mechanical barrier 442. 20 21 22 Once the ECT 410 has been assembled with the lower adapter 430 and the upper adapter 440, it is preferably fully tested prior to transporting it to the 1 well. The integrity of the adapters can be thoroughly tested with simultaneous 2. access to both ends of the ECT 410. Since no high voltage equipment is 3 attached to the cable up to this point, the high power cable 412 can be high 4 voltage tested at the assembly point without concern for damage to other,5 equipment. The hydraulic lines 414 can be checked end-to-end. Fiber optic 6 lines, conductors and connectors can be fully tested. Calibration procedures 7 are carried out for any sensors (such as temperature sensors, pressure sensors, 8 flow rate sensors, etc. ) and other downhole equipment. Calibration of sensors located in the adapters or the ECT cannot be performed in prior art methods because both ends of the ECT are not accessible when the adapters are assembled at the wellsite.

11 12 13 The integrity of the adapters 430 and 440 can be tested by adding 14 halogens to the inside 411 of the ECT 410 with slight pressurization and then detecting any leaks by using a leak detector. A coiled tubing hanger 445 may 16 be connected to the upper adapter 440 at the assembly place or at the well 1,7 site. An electrical connector 448 is connected uphole of the tubing hanger 18 448. Thus, in the preferred method of the present invention, the electrical 19 connector 448, the tubing hanger 445, the upper adapter 440 and the lower adapter 430 are preassembled on the ECT 410 at a suitable on shore assembly 21 plant, fully tested, spooled on a reel and then transported to the well site. As 22 noted above, the ESP 420 and the associated equipment 422 may be attached 21 1 to the lower adapter 430 and fully tested at the assembly plant.

2 3 The ECT with the adapters can be pressurized with an inert gas such as 4 argon and fitted with a gauge to monitor the pressure. The pressurized gas not only provides a controlled environment inside the ECT 410 but it also 6 provides method of monitoring the integrity of the system during transportation 7 to the well site and during installation. A rapid pressure drop would indicate 8 damage to the system. Corrective actions are taken before installation or 9 deployment of the system into the well 435.

An important advantage of the ECT assembly with both the upper and 12 lower adapters 440 and 430 in place provides a tested well control barrier with 13 proven pressure holding capability on both ends of the ECT string. This allows 14 the ECT in combination with a stripper or blow out preventor (BOP) to be considered a reliable well control barrier during installation. This is not the case 16 with an ECT that has to be cut and prepared for attachment to the upper and 17 lower adapters above the wellhead as Is done by prior art methods. This

18 feature is very useful in offshore and subsea, installations where operating 19 procedures requires multiple well control barriers at all times. The ECT string made according to the above described method can be installed at the rig site 21 in less time and with lower safety and environmental risks than the 22 conventional methods described above.

22 1 12 13 14 2 The devices utilized in the coiled tubing strings are flexible enough so 3 that they can be spooled on reels. The strings made according to the present 4 invention are preferably fully assembled at the factory and tested from the s remote end (uphole end) of the tubing via the hydraulic lines and 6 communication links in the tubing. The specific devices, sensors and their 7 locations in the string depend upon the particular application. The assembled 9 string may have upsets at its outer surface. The string is transported to the 9 well site and conveyed into the wellbore via an injector head system with remotely adjustable head opening. In addition to the use of various sensors and devices In the spoolable strings of the present invention, it also allows integrating the devices with conventional designs without requIring them being flush with the outer diameter of the tubing.

As noted above, the coiled tubing is assembled onshore with a lower and an upper adapter and fully tested prior to transporting it to the well site.

17 Figure 5 and 6 show a lower adapter according to one embodiment of the 18 present invention which provides a first mechanical barrier between the 19 wellbore pressure and the coiled tubing Inside. Figure 5 shows a crosssection view of the lower adapter 500 connected to the bottom end of an 21 electro-coiled- tubing (ECT) 502, having the outer metallic or composite tubing 22 503 and an armored power cable 504 running inside the tubing 503.

23 12 13 14 15 16 The lower adapter 500 includes an anchor 507 fixedly attached to the outer surface 503a of the coiled tubing 503. The anchor 507 includes a male slip 509 attached to the tubing surface 503a and a female slip 511 connected onto the male slip. The power cable 504 extends from the bottom and 512 of the coiled tubing 503. A hollow member 516 having an outer threaded section 1 6a is screwed into the inner threaded section 5 11 a of the female slip 511.

The member 516 is disposed around a segment of the power cable 504 and 9 includes an outer threaded section 516b. A first or upper sleeve 518 is threadably attached to the member 516 at the threaded upper inside section 518a of the sleeve 518. 0-rings 522 between the upper sleeve 518 and the member 516 provide a first mechanical barrier between the pressure in the adapter below the o-rings 522 and the coiled tubing inside 501. The seal 522 prevents flow of fluids from the wellbore to the inside 501 of the coiled tubing 502.

17 The lower end of the power cable 504 terminates inside the upper 18 sleeve 518. An electrical connector 530 is connected to the lower end 504a 19 of the power cable 504. The electrical connector 530 is adapted to mate with a connector (described later) attached to the a power cable connected to an 21 ESP or another device to transfer power and other electrical signals from the 22 power cable 504 to the ESP, The electrical connector 530 acts as a 24 il 2 3 hermetically-sealed feed through connector. Such connectors are typically molded parts and are commercially available. The cable 504 terminates inside the connector 530 and seals electrical conductors of the cable 504 from 4 exposure to the environment. A sliding member or sleeve 532 is disposed outside the upper sleeve 518. A shipping cap 536 connected to the sliding 6 sleeve 518 protects the connector 530 during transportation and handling of 7 the coiled tubing 500. The connector 530 is installed at the coiled tubing end 8 onshore or at the factory. This connector enables testing of the coiled tubing 9 500 at the point of manufacture.

11 Figure 6 shows a connector 550 that is adapted for connection with the 12 connector 530 and the ESP. The connector 550 includes a feed through 13 connector 560 whose upper end 562 mates with the lower end 534 of the 14 feed through connector 530 (Figure 5). A lower sleeve 564, when attached to the sleeve 532, allows the connectors 530 and 560 to mate. The top end 565 16 of the power cable 566 coupled to an ESP is connected to the connector 560.

17 The power cable 566 is enclosed in a shear assembly 568 that is connected 18 at its bottom end to a flange 570, which is coupled to a corresponding flange 19 (not shown) of the ESP. The bottom end 572 of the power cable 564 is connected to the ESP. The upper adapter 440 (see Figure 4) is substantially 21 similar to the connector 500 turned upside-down by 180.

22 11 1 Thus, the lower or bottom coiled tubing adapter includes a hydraulic 2 disconnect or shear release system, a dry-matable electrical connector, with a 3 scaling assembly isolating inside of the coiled tubing, thus providing a first 4 mechanical barrier to the wellbore environment. The upper or top coiled tubing 5 adapter contains a wet-matable connector and a mechanical arrangement for 6 connection with a tubing crown plug. The second mechanical barrier is part of the connectorlplug arrangement.

Thus, one system of the present invention includes a power cable, a 10 coiled tubing, a bottom coiled tubing adapter, and an upper adapter, all 11 assembled and tested onshore prior to installation In a wellbore. This system 12 has several advantages, which include (a) assembly of the major power 13 connectors is performed in a protected environment, such as a manufacturing 14 at the assembly plant followed by extensive testing and certification of the 15 entire system; (5) welding technology can be used to assemble the coiled 16 tubing system, which is not available at offshore figs due to safety regulations; 17 (iii) ability to maintain at least two mechanical barriers during installation of the 18 ESP; and fiv) significant simplification of the installation and rig time savings.

19 21 22 The above adapters provide a pre-terminated ECT system which can be utilized both offshore and onshore. This system eliminates the need for connecting the adapters and testing the integrity of the ECT at the rig site 26 1 1 before deployment of the ECT into the wellbore, thereby eliminating a number 2 of time consuming operations at the rig site. The ECT described herein is more 3 reliable, easier to use compared to systems that require installation of the 4 adapters in the field or rig site.

6 While the foregoing disclosure is directed to the preferred embodiments

7 of the Invention, various modifications will be apparent to those sWilled in the 8 art. It is intended that all variations within the scope and spirit of the 9 appended claims be embraced by the foregoing disclosure.

27 il

Claims

1 WHAT IS CLAIMED IS:

1. A method of making a spoolable coiled tubing string prior to transporting said string to a well site for use in a wellbore, comprilsing:

6 providing a coiled tubing of sufficient length to reach a desired depth in 7 the wellbore, said coded tubing having an upper end and a lower end; 8 9 attaching a lower adapter at said lower end of said coiled tubing prior to 10 transporting said coiled tubing string to the well site, said lower adapter 11 including a first pressure barrier between said wellbore and inside of said coiled 12 tubing, said lower adapter also adapted for attachment to a downhole device; 13 and 14 is 16 17 18 19 2. The method of claim 1 further comprising attaching a tubing hanger to the upper adapter for hanging the coiled tubing string to a wellhead equipment 21 at the wellbore.

22 attaching an upper adapter to said upper end of the coiled tubing prior to transporting said coiled tubing string to the well site. said upper adapter adapted for connection to a device at the well head.

28 3. The method of claim 2 further comprising attaching an electrical connector uphole of the tubing hanger, said electrical connector adapted to mate with an external connector.

4 4. The method of claim 1 further comprising providing a second pressure penetrator proximate to said upper end of said coiled tubing, said second pressure penetrator providing a pressure barrier between the inside of the coiled tubing and the atmosphere.

6 7 8 9 5. The method of claim 1 wherein said coiled tubing includes a power 11 cable therethrough for carrying electrical power from said upper end to said 12 lower end. 13 14 15 16 17 18 19 20 21 22 8. The method of claim 8 further comprising filling said coiled tubing with a 6. The method of claim 1 wherein said coiled tubing further includes at least one hydraulic line for carrying a pressurized fluid and at least one line for carrying signals.

7. The method of claim 1 further comprising testing said coiled tubing string for defects in said coiled tubing string prior to transporting said string to the well site.

29 1 fluid under pressure for determining leaks during one of transportation and 2 storage of said string. 3 4 9. The method of claim 1 wherein the lower adapter is welded to the coiled 5 tubing. 6 7 10. The method of claim 9 wherein the upper adapter is welded to the 8 coiled tubing. 9 10 11. The method of claim 1 further comprising attaching an electrical 11 submersible pump to the lower adapter for pumping a fluid from the wellbore 12 to the surface. 13 14 15 16 17 13. The method of claim 12 wherein said sensor is selected frorn a group 18 consisting of 0) a pressure sensor, fli) temperature sensor, (M) a flow rate 19 sensor, 0v) a vibration sensor, and (v) a corrosion measuring sensor. 20 21 22 12. The method of claim 1 wherein said coiled tubing includes at least one sensor for providing signals responsive to at least one downhole parameter.

14. The method of cWim 12, wherein said downhole parameter is selected from a group consisting of (i) pressure, (ii) temperature, (iii) flow rate, Ov) 1 vibration and (v) corrosion.

2 3 15. The method of claim 1 wherein said coiled tubing includes a fiber optic 4 line for providing one of (i) a measure of a downhole parameter and (5) a data communication link.

6 7 16. The method of claim 1 further comprising coupling an electrical 8 submersible pump to the lower adapter.

9 10 17. The method of claim 16 further comprising Inserting the coiled tubing In 11 the wellbore with an adjustable-opening injector head.

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