BR122015004451B1 - suspend well method, finish well method, method of repairing a finished well, suspended well, finished well, double barrier system, underwater well finish method - Google Patents

Description

REPORT

WELL SUSPEND METHOD, WELL FINISH METHOD, METHOD

REPAIR OF A FINISHED WELL, SUSPENDED WELL, FINISHED WELL, DOUBLE BARRIER SYSTEM, SUBWAY WELL FINISHING METHOD (APPLICATION DIVIDED FROM APPLICATION PI0413431 '1, DEPOSITED ON 06.08.2004) Field of the Invention [0001] A method of suspending, finishing or repairing a well and particularly, but not exclusively, a method of suspending, finishing or repairing a well while maintaining at least two deep mounting barriers.The present invention additionally relates to a suspended or finished well provided. with at least two deep mounting barriers.

The methods of the present invention pertain to any type of well, including underwater wells, platform wells and land wells. The present invention relates particularly, although not exclusively to wells used for oil and / or gas production, and gas and / or water injection wells.

Background of the Invention To provide adequate well control and to meet the statutory safety requirements of many jurisdictions around the world, most operating companies adopt the principle of ensuring that at least two barriers are in place at all times. construction or suspension of wells. The term "barrier" as used throughout this report refers to a physical measure that is capable of forming a seal to prevent uncontrolled release or flow of fluid from the pressure side of the barrier. Well construction operations include all activities from the moment the well is drilled until the well is finished ready for production by installing a production flow control device. The most commonly used production flow control devices are typically referred to as "Christmas trees".

During well construction operations when at least two barriers can be installed and checked at the wellbore, the well may be termed “suspended.” A well may not be temporarily suspended or permanently abandoned without ensuring that the wells at least least two required independently verified barriers are in place.

From time to time during the life of a producing well, corrective action such as repair or maintenance is required. Such remedial action operations, including interventions, are referred to throughout this descriptive report as “remediation operations.” When a remediation operation is required, it is typically again a statutory safety requirement for many jurisdictions around the world. at least two independently verified barriers are in place at all times.

Often, several wells are constructed to penetrate a given reservoir or formation of oil and / or gas. Depending on the geology of a particular site, as well as programming requirements, it is common for one or more of the wells to be temporarily suspended for a period of time. These suspended wells can again be penetrated and finished as producing or development wells in a well. later date. In some locations, each well is drilled and finished sequentially. Elsewhere, well construction operations may be “series”. When series operations are used, well construction processes are performed in discrete steps. For example, a first sequence of steps is conducted in a number of wells, followed by a second sequence of steps being conducted in these wells. The process is repeated until each well has been finished. Serial operations are used to allow well construction operations to be logistically optimized or for finishing operations to be performed using a different vessel or rig typically smaller than that used for drilling.

Typically, the first step in building a well involves drilling a wellbore. Figure 1 illustrates an example of a typical underwater well 10 which has been drilled but not yet suspended. Referring to Figure 1, well 10 is provided with a wellhead 11 and a guide base 12. An underwater BOP exhaust pipe 40 as well as its associated marine riser 42 is positioned on wellhead 10 to provide control of the wellhead 10. well during drilling operation. Subsequently, well control is achieved by placing at least two independently verified barriers at another location.

Drilling continues to extend the borehole and casing piping is sequentially installed in well 10. In the example illustrated in Figure 1, a first casing piping 14 with a nominal size of 76.20 cm is installed first. . A second casing pipe 16 with a nominal size of 50.80 cm is extended with wellhead 11 and cemented into position. A third casing pipe 18 having a nominal size of 12.19 cm is provided within the second casing pipe 16. A fourth and final casing pipe 20 having a nominal size of 14.22 cm is provided within the third piping 18.

For platform wells, casing pipes may extend above the mud line or the seabed to a rig floor 46 or basement floor 44 of the platform. The wellhead is typically located at the highest end of the wellbore in the underwater well mud line, at the platform level for platform wells or at ground level for terrestrial wells.

After the required number of casing pipes has been installed, it is common but not essential to install an inner pipe 22 which is a column of pipes that does not extend to the surface. The inner tube is typically suspended from a tube hanger 24 installed within the lower casing piping 20.

During drilling a well, it is common to maintain sufficient hydraulic fluid pressure in the wellbore to provide excessive compensation for the expected reservoir pressure or formation into which the well is being drilled. When the well must be suspended, other barriers must be provided.

[0011] The requirement for a second barrier to be in place at all times is met during drilling and coating operations by positioning an explosion-proof exhaust pipe (BOP) at the top of the well. Some of the casing piping, inner tube, tube hanger, first barrier, and finishing piping are all passed through the hole in the BOP exhaust pipe. For subsea wells not using a surface BOP exhaust pipe, the bottom hole equipment should also be extended through the marine riser hole associated with the subsea BOP exhaust pipe.

To accommodate the routing of borehole equipment through the BOP exhaust pipe, the BOP exhaust pipe typically has a nominal internal bore diameter of 34.29 centimeters and is therefore an extremely large piece of equipment. For underwater wells, the time taken to route and / or retrieve the BOP exhaust pipe depends on the distance between the waterline and the mudline, and in deep water may take several days. The economic viability of offshore operations depends directly on the time taken to carry out the various construction operations. Thus, routing and retrieval of a BOP exhaust pipe are considered to be some of the most expensive operations associated with underwater well construction. [0013] Using prior art methods, a first barrier, “ΒΓ is typically mounted above the reservoir. If the well is to be suspended, a second barrier, “82”, must be established and verified elsewhere in the well hole before the BOP exhaust pipe can be removed. [0014] It has long been well-accepted industry practice to position the required second barrier, B2, towards the highest end of the well bore and typically into the wellhead 11 or the highest end of the final casing pipe 20 with reference to Figure 2. This second barrier, B2, was traditionally shaped like a cement plug, but more recently, however, the use of cement plugs has been replaced by the use of b mechanical trims to overcome some of the cleaning issues associated with removing the cement plugs. The types of mechanical barriers being used as the second barrier include recoverable drill pipe or wire line devices such as plugs and shutters.

There are several factors that motivate operating companies to place the second barrier towards the top of the well. One of the main reasons is the reduced cost of forwarding and / or recovering the second barrier when it is placed towards the top of the borehole. from the well. It is also widely accepted that the first and second barriers should be placed as far apart as possible to facilitate independent verification of each barrier. If the first and second barriers are mounted close together, it has been considered prohibitively difficult to independently verify the integrity of the second barrier. The integrity of the first barrier is verified by filling the wellbore with a fluid and pressurizing the fluid column to a specified pressure. Due to the compressibility of the trapped fluid or gas, the pressure typically drops for a short time before leveling. If the barrier is leaking, the pressure does not level.

This procedure is repeated after the second barrier is installed. When the second barrier is positioned at the higher end of the wellbore, the amount of fluid required to pressurize the wellbore during pressure tests is greatly reduced if the second barrier has integrity. This makes it easy to detect if fluid is passing through this upper barrier.

To prepare the well for production, a 'finishing pipe' is installed in the wellbore. The term “finishing pipe” as used throughout this descriptive report refers to the pipe and equipment that is installed in the wellbore to allow production from a formation. The upper end of the finishing pipe typically ends at, and includes a pipe hanger from which the finishing pipe is suspended. Finishing tubing typically includes an annular production plug positioned toward the lower end of the finishing tubing. The plug isolates the annular ring from the wellbore from the finishing pipe, the annular ring being the space through which fluid can flow between the finishing pipe and the casing pipe and / or inner tube. The lower end of the finishing tubing is commonly referred to as a "tip pipe".

When the well is ready for production, oil, water and / or gas passes through the inner tube or casing and through the finishing tubing to a production flow control device located on or above the wellhead. .

Prior art well suspension methods require removal of the upper layer before the well can be finished. To provide the second required barrier, the BOP exhaust pipe must be reinstalled above the well in what has long been a commonly used industry practice. The BOP exhaust pipe cannot be removed until at least two barriers are established elsewhere. The requirement to install a BOP exhaust pipe creates a number of problems. First, operations that must be performed prior to removal of the BOP exhaust pipe are limited to tooling) which can pass through the inside diameter of the BOP exhaust pipe bore. Second, the BOP exhaust pipe bore (and its associated marine riser for underwater wells) may contain fragments such as swarf, cement and / or chips in the ram or annular cavities of the BOP exhaust pipe, as well as fragments in the lines. drill and / or drowning and / or corrosion product in the marine riser. Consequently, one of the problems with current well-building practice is the high level of debris that accumulates when the finishing piping and other equipment passes through the BOP exhaust pipe bore and / or its associated marine riser. Third, the need to route or retrieve the BOP exhaust pipe during well construction operations can add considerable expense to the cost of these operations with costs being directly proportional to the amount of rigging time that must be allocated to these operations.

There is a need for a less time consuming and therefore less expensive well construction method.

It will be clearly understood that although the use of the prior art is referred to herein, such reference does not constitute an admission of the same as forming part of the general common knowledge in the art in Australia or any other country.

In the summary of the invention and in the following description and claims, except where the context otherwise requires due to the expressed language or any other implication, the word "understand" or variations such as "understand" or "understanding" is used in a sense inclusive, that is, to specify the presence of the stated features, but do not preclude the presence or addition of additional features in various embodiments of the invention.

SUMMARY OF THE INVENTION The present invention is based on an advanced perception that well construction operations can be radically simplified by positioning each of at least two independently verifiable barriers below the anticipated depth of the lower end of the pipe. termination. By not placing any higher barriers in the wellbore, both barriers can remain in place during suspension and finishing operations, thus avoiding the need to use a BOP exhaust pipe to supplement well control. This results in considerable savings in drilling rig time and thus significantly reduces the cost of building a well.

The term "barrier" as used throughout this specification refers to a physical measurement that is capable of forming a seal to prevent uncontrolled release or flow of fluid from the pressure side of the barrier. To serve the function of a barrier, the physical measurement must be able to maintain its position in the wellbore. The barrier need not be recoverable. Various physical measures may be used in combination with the provision of the barrier, one or more of the measures serving as a sealing means and one or more other measures being used to hold the barrier in position, typically against an inner wall of one of the pipes. coating or lining.

The term "deep mounting barrier" as used throughout this specification refers to a barrier that is located below the depth of the lowest end of a pipe column (typically suspended from a pipe hanger). or other equipment) when the pipe column is installed in its final position in the well.

The term "BGP exhaust pipe" as used in this descriptive report includes surface BOP as well as subsea BOP. The BOP tailpipe would typically comprise a combination of pipe and blind ram, annular preservers, drowning and extinction lines and may include a lower connector and an upper and / or lower marine riser.

According to one aspect of the present invention there is provided a method of suspending a well: providing a first barrier in the well; verified integrity of the first barrier; providing at least a second well barrier at a location above the first barrier to define a gap between the first and second barriers; and checking the integrity of the second barrier; the first and second barriers being below a lower end of a finishing pipe when the finishing pipe is installed in the well and remaining in position while the well is suspended.

Preferably checking the integrity of the second barrier further comprises measuring the pressure in the space between the first and the second barrier.

Preferably one or both of the first barrier and the second barrier is selected from the group consisting of: a cement shutter; an unperforated inner tube; a section of non-perforated coating; an inner tube upper valve; a bridge plug; a framer; an expandable plug; a retractable plug; a rupture disc; or an inflatable plug shutter.

One or both of the first barrier and the second barrier may be provided as a combination of a physical device, a device for holding the physical device in position in the well, and a sealing means. Preferably the sealing means is selected from the group consisting of; a ball valve; a hinged valve; a sliding glove; a pressure cycle plug; a retrievable plug of wire line; a rupture disc; a forming insulation device; a shear disc; and a pump opening device.

The sealing means may be positioned distally from the physical device or at the same location.

Preferably the method further comprises installing a first inner tube hanger or a first inner tube hanger and a second inner tube hanger in the well. More preferably, one or both of the first barrier and the second barrier is provided within the first or second inner tube hanger.

Alternatively or additionally the method further comprises installing a first inner tube or a first inner tube and a second inner tube in the well. More preferably one or both of the first barrier and the second barrier is provided within the first and second inner tube.

Preferably the well comprises at least one casing pipe and the first and / or second barriers are provided within at least one casing pipe.

According to a second aspect of the present invention there is provided a method of finishing a well comprising: providing a first barrier in the well; check the integrity of the first barrier; subsequently providing at least a second barrier in the well at a location above the first barrier to define a gap between the first and second barriers; check the integrity of the second barrier; rely on the first and second barriers to provide well control during installation of a finisher in the well, the finisher having a lower end; and installing a production flow control device in the well to regulate fluid flow through the well; the first and second barriers being below the lower end of the finishing pipe when the finishing pipe is installed in the well.

Preferably the method further comprises installing a pipe reel in the wellhead prior to the step of installing the finishing pipe in the well.

[0036] The production flow control device may be a Christmas tree.

Preferably the production flow control device is a horizontal Christmas tree. More preferably the horizontal Christmas tree includes a body, the finishing tubing terminates at its upper end and is suspended from its tubing hanger, and the method further comprises the step of forming an assembly comprising the horizontal Christmas tree and the pipe hanger by placing and locking the pipe hanger in the horizontal Christmas tree body prior to the step of installing the production flow control device in the well.

Alternatively, the Christmas tree is a vertical Christmas tree.

According to a third aspect of the present invention there is provided a method of repairing a finished well, the finished well including a production flow control device and a finisher installed in the wellbore, the finisher having a higher end terminating in a pipe hanger from which the finishing pipe is suspended and a lower end, the method comprising: providing a first barrier in the well; verified integrity of the first barrier; subsequently providing at least a second barrier in the well at a location above the first barrier to define a gap between the first and second barriers; check the integrity of the second barrier; rely on the first and second barriers to provide well control during removal of the pipe hanger, trim piping, and / or production flow control device from the well; and, the method characterized in that the first and second barriers are below the depth of the lower end of the finishing pipe when the finishing pipe is installed in the well.

Preferably the horizontal Christmas tree comprises a body and the method of repairing the well further comprises the step of removing the piping hanger and / or trim piping from the horizontal Christmas tree body by unlocking the tubing hanger. from the body of the horizontal christmas tree.

Alternatively the horizontal Christmas tree comprises a body and the method of repairing the well further comprises the step of removing the horizontal Christmas tree and the finishing tubing as a set.

Preferably the method of repairing the well further comprises the step of relying on the first and second barriers to provide well control until the pipe hanger, trim pipe and / or production flow control device is reinstalled. in or in the well.

According to a fourth aspect of the present invention there is provided a suspended well comprising: a well bore having a higher end; a wellhead installed towards the highest end of the wellbore; and at least one independently verified first and second barrier positioned in a separate relationship in the wellbore to define a gap between the first and second barrier; the first and second barriers being below an anticipated depth of a lower end of a finishing pipe when the finishing pipe is installed in the well.

According to a fifth aspect of the present invention there is provided a finished well comprising: a well bore having a higher end; a wellhead installed towards the highest end of the wellbore; a production flow control device at or above the wellhead; a finishing pipe installed in the wellbore and having a lower end; and at least one independently verified first and second barrier positioned in a separate relationship in the wellbore to define a gap between the first and second barrier; the first and second barriers being below the lower end of the finishing pipe.

Preferably the suspended or finished well further comprises a pressure measuring device for generating a signal indicative of the pressure in the space between the first and second barriers. More preferably the suspended or finished well further comprises a signal receiving means for receiving a signal generated by the pressure measuring means. Even more preferably the suspended or finished well further comprises a means for transmitting the signal from the pressure measuring means to the pressure signal receiving means.

Preferably the pressure measuring means is a transducer.

The suspended or finished well may be an underwater well, a land well or a platform well.

Preferably the suspended or finished well additionally comprises a first inner tube or a first inner tube and a second inner tube installed in the well. More preferably one or both of the first and second barriers are positioned within the first and second inner tube.

Preferably the suspended or finished well includes at least one casing pipe and one or both of the first barrier and the second barrier is provided within the at least one casing pipe.

Preferably the finished well further comprises a tubing reel installed in the wellhead.

Preferably the production flow control device is a Christmas tree. More preferably the production flow control device is a horizontal Christmas tree. Alternatively, the production flow control device is a vertical Christmas tree.

According to a sixth aspect of the present invention there is provided a double barrier system for use in suspending, finishing or repairing a well, the double barrier system comprising: a first and second body barrier positioned in a separate relationship in the well and defining a space between the first and second barriers; a pressure measuring device which generates a signal indicative of pressure in the space between the first and second barriers; a pressure signal receiver receiving the signal generated by the pressure measuring devices; and, a transmitter that transmits a signal from the pressure measuring device to the pressure signal receiver.

According to a seventh aspect of the present invention there is provided a method of finishing an underwater well using a horizontal Christmas tree for production flow control, the horizontal Christmas tree having a body, the method comprising: forming an assembly by installing a finishing pipe terminating at its upper end in, and suspended from a pipe hanger in the horizontal Christmas tree body; and forward the set to the underwater well; the pipe hanger and the horizontal Christmas tree standing above the waterline during the formation of the assembly.

Preferably the formation of the assembly further comprises placing and locking the pipe hanger in the body of the Christmas tree. More preferably the method of finishing an underwater well using a horizontal Christmas tree for production flow control further comprises checking the integrity of the finished assembly above the waterline.

Preferably checking integrity comprises checking the hydraulic and electrical interfaces between the pipe hanger and the Christmas tree body. More preferably checking integrity further comprises checking the pressure integrity of the assembly.

Preferably routing the assembly to the wellhead comprises the step of utilizing a bottom-up tube package.

DESCRIPTION OF THE FIGURES Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates a typical drilled well prior to being suspended using prior art methods. well suspension;

Figure 2 illustrates a suspended well according to a common prior art method of well suspension;

Figure 3 illustrates a first step in a well finishing sequence of a first embodiment of the present invention showing the placement of casing and inner tube as well as deep-mounted double barriers while a BOP exhaust pipe is in place. in position;

[0061] Figure 4 illustrates a next step in a well finishing sequence of a first embodiment of the present invention showing a deep well suspended double wall suspended well;

[0062] Figure 5 illustrates one embodiment of a double barrier system for use in suspending a well;

Figure 6 illustrates a next step in a well finishing sequence according to the present invention showing partial formation of the HXT / TH assembly after suspending the well according to Figure 4;

[0064] Figure 7 illustrates a next step in a well finishing sequence according to the present invention showing the use of an LRP to route the HXT / TH assembly to the wellhead;

Figure 8 illustrates the next step in a well finishing sequence according to the present invention showing the HXT / TH assembly in position on the wellhead;

Figure 9 illustrates a still further step in a well finishing sequence according to the present invention showing installation of double barriers in the pipe hanger and / or tree cap or combined hanger / cap assembly;

Figure 10 illustrates a final step in a well finishing sequence according to the present invention showing a finished well with double barriers in the pipe hanger and pipe hanger cap;

Figure 11 illustrates a step in a well finishing sequence from a first embodiment of the present invention to a well using a vertical Christmas tree for production flow control, showing the use of a THRT and guidance mechanism for orient, fit and lock the pipe hanger on the wellhead;

Figure 12 illustrates a next step in a well finishing sequence in a first embodiment of the present invention showing the vertical Christmas tree with LRT and EDP being prepared on the basement floor;

Figure 13 further illustrates a further step in a well finishing sequence of a first embodiment of the present invention showing the well after the vertical Christmas tree, LRP and EDP have been installed above the pipe hanger;

Figure 14 illustrates a next step in a well finishing sequence of a first embodiment of the present invention showing the well when the deep mounting barriers were removed relying on the vertical christmas tree flow control valves. and / or LRP set to meet statutory requirement for at least two verifiable barriers;

Figure 15 illustrates the finished well of the first embodiment of the present invention with a tree cap in place;

Figure 16 illustrates the step in a well finishing sequence according to a second preferred embodiment of the present invention showing the placement of a tubing reel on the wellhead after suspending the well according to Figure 4;

Figure 17 illustrates a next step in a well finishing completion sequence of a second embodiment of the present invention showing the use of a THRT and guiding mechanism to orient, place and lock the pipe hanger on the pipe reel. ;

Figure 18 illustrates a next step in a well finishing sequence of a second embodiment of the present invention showing the vertical Christmas tree with an LRP and EDP being prepared on the basement floor while maintaining the double deep mounting barriers;

Figure 19 further illustrates a further step in a well finishing safety of a second embodiment of the present invention showing the well after the vertical Christmas tree, LRP and EDP have been installed above the pipe hanger with the barrier barriers. deep mounting removed and relying on the flow valves in each vertical hole of the vertical Christmas tree and / or LRP assembly; and Figure 20 illustrates the finished well of the second embodiment of the present invention with a Christmas tree in place; and Figures 21 to 23 illustrate alternative embodiments of double barrier systems such as those illustrated in Figure 5.

Description of Preferred Embodiments Prior to describing the preferred embodiments of the present invention, it should be understood that such invention is not limited to a specific sequence or types of barriers described. It is also to be understood that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the scope of the present invention. Unless otherwise defined, all technical and scientific terms used herein have the same meanings commonly understood by those of ordinary skill in the art to which this invention belongs.

While other types of barriers and specific well finishing and / or recovery sequences similar to or equivalent to those described herein may be used to practice or test the various aspects of the present invention, preferred barriers and methods are now described with reference to suspension, finishing and recovery of an underwater well. It should be clearly understood that the present invention is equally applicable to land wells as well as platform wells.

It should be noted that Figures 1 to 20 are not scaled and that the length of the various pipe columns, liners and / or inner tube will vary depending on the requirements of a specific location such as the water depth above the line. mud and the depth and geology of the reservoir or specific formation being drilled. As an example, for subsea wells the mudline should be on the order of 20 to 3,000 meters below the waterline with the reservoir or formation being on the order of one to three kilometers below the mudline.

It should also be noted that the underwater Christmas tree of the illustrated example of Figures 3 to 10 is a type of single hole whereas the underwater Christmas tree of the illustrated example of Figures 11 to 15 and 17 to 20 is of a type double hole. It should be clearly understood that the various aspects of the present invention are equally applicable to single hole, double hole or multi hole wells.

A first preferred embodiment of the method of suspending a well is illustrated in the sequence of Figures 3 and 4. With reference to Figure 3, an underwater well 10 has been drilled and provided with a wellhead 11 and a guide base 12. The submarine BOP exhaust pipe 40 as well as the associated marine riser 42 is positioned on the wellhead to temporarily control the well. Subsequently, well control will be achieved by placing at least two independently verified barriers elsewhere.

A required number of casing piping is installed in well 10. In the embodiment illustrated in Figure 3, a first casing piping 14 with a nominal size of 76.20 cm is installed first. A second casing piping 16 , with a nominal size of 50.80 centimeters, is placed with wellhead 11 and cemented into position. A third casing pipe 18 having a nominal size of 49.53 centimeters is provided within the second casing pipe 16. A fourth and final casing pipe 20 having a nominal size of 57.15 centimeters is provided within the third casing pipe 18

It is to be understood that while four concentric casings are illustrated in Figure 3, the present invention is equally applicable to subsea wells provided with any number of casings of other nominal sizes as required.

Referring to Figure 3, an inner tube 22 is then installed within the final casing pipe 20. The inner tube 22 is suspended from a first inner tube hanger 24. It should be understood that while an inner tube 22 and an inner tube hanger 24 are used in the embodiment illustrated in Figure 3, the method of suspending a well is equally applicable to wells that do not use inner tubes or inner tube hangers. A first deep mounting barrier 26 is installed on the first inner tube hanger 24 and / or first inner tube 22. The integrity of the first barrier 26 is then verified. A second inner tube hanger 28 together with a second inner tube 23 is then positioned within the final casing pipe 20 above the first inner tube hanger 24, defining a space 35 therebetween. A second deep mounting barrier 30 is placed within the second inner tube hanger 28 and / or second inner tube 23 and the integrity of the second barrier 30 is independently verified. A preferred embodiment for providing the two deep mounting barriers, independently verified, in the form of a double barrier system 32, is illustrated in Figure 5. Referring to Figure 5, the first barrier 26 is provided by the combination of a physical measurement in the form of a first plug 25 and a separate sealing means. in the form of a first annular seal 27. The first plug 25 is secured in position and forms a seal through the hole of the first inner tube hanger 24 and / or first inner tube 22. The first annular seal 27 is provided with the first inner tube hanger 24 and / or first inner tube 22 to form a seal between the outer diameter of the first inner tube hanger 24 and / or first inner tube 2 2 and the inside diameter of the final lining tubing 20. The integrity of the first barrier 26 is then verified using known techniques.

The second barrier 30 of the double barrier system 32 as illustrated in Figure 5 is provided by first installing a second inner tube hanger 28 together with the second inner tube 23 above the first inner tube hanger 24 defining a 35 space between them.

The second barrier 26 is provided by combining a physical measure in the form of a second plug 27, typically a recoverable wire line plug, and a separate sealing device in the form of a second annular seal 29. The second plug 27 is secured in position and forms a seal through the hole of the second inner tube hanger 28 and / or second inner tube 23. The second annular seal 29 is provided with second inner tube hanger 28 and / or second tube. 23 to form a seal between the outer diameter of the second inner tube hanger 28 and / or the second inner tube 23 and the inner diameter of the final casing pipe 20.

The integrity of the second barrier 30 can then be verified. It was previously considered that barriers relied upon to provide well control during well completion and / or recovery operations should not be positioned close together as discussed above. This is because it is considered difficult to verify the independence of the second barrier if the space between the two barriers has a relatively small volume. [0091] This problem is overcome in the embodiment illustrated in Figure 5 by providing a pressure measuring device in the form of a pressure transducer 34 in the space 35 between the first and second barriers. The pressure transducer 34 is capable of generating a signal indicative of pressure in space 35. The signal from the pressure transducer 34 is transmitted using any suitable medium such as a wireless signal, breakable wiring or disconnectable wire line to a pressure signal receiver.

In the embodiment illustrated in Figure 5, the pressure signal receiver 36 is incorporated into a plug routing tool 38 in electrical communication with a means for interpreting the pressure signal (not shown) positioned above the waterline, typically accessed on the floor 46 of the rig and less preferably on the floor 44 of the basement.

It should be understood that the pressure transducer 34 need not be provided with the second barrier 30, the only provision being that the pressure transducer 34 is capable of generating a signal indicative of the pressure in the space between the first and second barrier. . The pressure transducer 34, therefore, may also be positioned on a higher face of the first barrier, an inner diameter of the inner tube hanger or an inner diameter of a section of the lower casing pipe.

In use, the signal from the pressure transducer 34 is received and interpreted by the pressure signal receiver 36 enabling independent verification of the integrity of the second barrier 30 after the integrity of the first barrier 26 has been independently verified.

The placement of at least two independently verifiable barriers within the inner tube hangers in the preferred embodiment represents one way of placing such barriers. Other options for providing the first and second barriers to the double barrier system as described below with reference to Figures 21, 22 and 23.

[0096] In Figure 21 the first (lower) barrier 26 is provided either by means of an inner tube top insulating device, a multiple action reciprocating device, a ball valve or a hinged valve that forms a barrier through of the total bore width of the inner tube 22. The second (upper) barrier 30 is provided by a mechanical device such as a retrievable wire line plug also installed in the first inner tube 22.

[0097] In Figure 22, the first barrier 26 is provided by means of a recoverable full bore wire line or cement plug device in the first inner tube 22. The second barrier 30 is provided by an insulation device. inner tube end, a multiple action reciprocating device, a ball valve or hinged valve also installed on the first inner tube 22.

In Figure 23, the first barrier 26 is provided by means of a cement plug or recoverable full-length wire line in the first inner tube 22. Second barrier 30 is provided by a cement plug or recoverable of wire line installed for sealing through the full hole of the final lining pipe 20.

[0099] The first and / or second barrier in this manner may also be selected from the group consisting of: a cement plug; an unperforated inner tube; a section of non-perforated tubing; an inner tube upper valve; a bridge plug; a framer; an expandable plug; a retractable plug; a rupture disc; and / or an inflatable plug plug.

Each or both of the first and second barriers may be provided using a combination of a means for securing the seal in position and a separate sealing means. The means for maintaining the sealing position, and the sealing means, need not be located in the same position on the liner tubing, inner tube and / or inner tube hanger. Suitable sealing means include, but are not limited to the following: a ball valve; a hinged valve, a sliding glove; a pressure cycle plug; a retrievable plug of wire line; a rupture disc; a forming insulation device; a shear disc; and / or a pump opening device.

A hydrostatic fluid column in the wellbore may be considered sufficient to serve as one of the barriers provided at which the fluid column level can be monitored and redone if required. This option may be used to finish a well in accordance with preferred embodiments of the present invention. However, while a hydrostatic fluid column need not be removed to facilitate installation of the finisher tubing in the borehole, reliance on such a barrier is typically not acceptable, particularly for well suspension, unless it is used for formation. having subnormal formation pressure.

Having provided the well 10 with two independently verified, deep-mounted barriers 26 and 30, the riser BOP 40 can be removed and recovered for rigging. The well, as illustrated in Figure 4, can now be considered suspended. The well may be finished at this time or left in this condition for finishing after a period of time.

An advantage of being able to suspend the well in this condition, that is with the first and second deep mounting barriers in position, is that it is possible for the first time to install the finishing piping in the well without the need to provide a rising pipe BOP to provide one or both barriers.

A further advantage of being able to suspend the well in this condition with at least two deep mounting barriers is that it is possible to drill and suspend a plurality of wells at a given location above a formation using the type of drillings that accommodate the tube. ascending BOP 40 and other tube parts for the lining, inner tube, and finishing pipes. When the various wells have been suspended as shown in Figure 4, riser tube BOP 40 is no longer required and the drill rig can be moved to another location. In addition, by drilling and suspending a plurality of wells using the embodiments of the present invention, the BOP 40 riser can be moved laterally (under water) from one well to the next and does not necessarily need to be recovered back to the well. rigging between wells. There is therefore the potential for the finishing of suspended wells to be done using a smaller type of vessel than is normally required for the installation of the pipe hanger and vertical tree.

Another advantage of being able to suspend the well as shown in Figure 4 is that it is possible to perform pipe hanger spacing measurements by ROV while the well is suspended when required.

[00106] The sequence of steps used to finish the production-ready well depends in part on the type of production flow control device or Christmas tree that was chosen to control the flow from the well during production. It should be understood that embodiments of the present invention are not limited to the specific type of device used to control the flow of fluids to and / or from the well. Christmas trees are broadly categorized into two types; that is, horizontal Christmas trees and vertical Christmas trees.

[00107] A method of finishing and / or repairing an underwater well using a horizontal Christmas tree as the production flow control device is described below. A typical prior art method of well finishing using horizontal Christmas trees is based on the following sequence of steps: a) a BOP riser is used to provide well control while the well is drilled and lined and an inner tube (optional) is installed; b) a first barrier is placed in place in the general area above the formation or reservoir; c) the integrity of the first barrier is verified; d) thereafter, a second barrier is positioned towards the highest end of the well bore or in the wellhead; e) the integrity of the second barrier is verified; f) thereafter, the BOP riser tube is removed from the wellhead to facilitate installation of the horizontal Christmas tree on the wellhead; g) the riser pipe BOP is re-routed and positioned in the horizontal christmas tree to provide well control when the second (upper) barrier is removed to facilitate passage of the finishing tubing into the well hole; h) a pipe hanger routing tool is used in combination with an subsea test tree (SSTT) to route the suspended finish pipe from a pipe hanger through the inner hole of the subsea BOP riser pipe and its riser pipe associated maritime; (i) the pipe hanger is oriented, placed and locked within the body of the underwater Christmas tree; j) the lower barrier is removed; k) a new first barrier is provided in the pipe hanger and checked; I) a new second barrier positioned above the first, typically on an internal and verified tree cover; and, m) when the integrity of the new first and second barriers is verified, the subsea BOP riser can be recovered and the well is ready for production.

One embodiment of the well finishing method of this aspect of the present invention for wells using a horizontal Christmas tree as the production flow control device is illustrated with reference to the suspended well of Figures 3, 4 and 6 to 10. Underwater well 10 is drilled and suspended as described above with reference to Figures 3 and 4.

Referring to Figure 6, a horizontal Christmas tree 50 is positioned on the basement floor 44 below the rigging floor 46. A tubing hanger 60 has been installed within the horizontal Christmas tree body 50. A trim tubing 62 is suspended from the tubing hanger 60 and is provided with a bore bottom relief valve 64 and a plug assembly 65. The horizontal christmas tree has a body 52 including a shoulder 54 against which a correspondingly formed shoulder 63 of the pipe hanger 60 abuts when the pipe hanger 60 has been placed in the body 52 of the horizontal christmas tree 50. The horizontal Christmas tree 50 may also be provided with a spiral (not shown) to guide the pipe hanger 60 within the horizontal Christmas tree 50.

[00110] Piping hanger 60 installation on the horizontal Christmas tree is conducted above waterline 66 and more specifically on basement floor 44 below rig floor 46 to form a combined set of horizontal Christmas trees. / pipe hanger (hereinafter referred to as HXT / TH assembly) 70 which can be lowered to the well position after installation has been verified. To verify the integrity of the HXT / TH 70 assembly, all electrical and hydraulic connections are checked. The HXT / TH 70 set can also be pressure tested.

The ability to install the pipeline hanger on the horizontal Christmas tree body above the waterline and preferably over the hold of a rig or vessel provides significant advantages over having to install and check connections subsea.

Referring to Figure 7, a lower riser pack (LRP) 80 is positioned above the HXT / TH 70 assembly while the HXT / TH 70 assembly is on hold 44. The LRP 80 is provided with battering ram and / or valves in their vertical bore as a means of providing a barrier. The LRP 80 has an Emergency Disconnect (EDC) connector 90 attached to it to allow disconnection from the LRP 80 if necessary, for example under stormy conditions.

Referring to Figure 8, when LRP 80 has been installed, the HXT / TH 70 assembly and LRP 80 are routed to the wellhead in a single operation. During routing of the HXT / TH 70 assembly to wellhead 11, well control is provided by the first and second barriers 26 and 30, respectively, which remain in position.

A fixture riser In this example, a single-hole finish riser 92 is positioned above the LRP, ending in a surface flow tree 88. Finishing riser tube is commonly supported and tensioned to accommodate rig movement due to sea conditions. Surface flow tree 88 in conjunction with LRP 80 allows proper pressure control to be maintained to facilitate operation of the rig. wire line and / or well cleaning if desired.

When the HXT / TH 70 assembly has been installed in wellhead 11 integrity is checked by testing. LRP 80 rams / valves and / or surface tree 88 valves and / or valves on horizontal Christmas tree 50 are then relied upon to meet the statutory requirements of two independent barriers during removal, typically via wire line. , of the first and second barrier, 26 and 30, respectively. The first and second barriers 26 and 30, respectively, are removed at this stage to prepare the well for production.

Referring to Figure 9, after removal of the first and second barriers 30 and 26, respectively, two new independent barriers shall be installed above the level of the HXT / TH 70 fluid outlet port 68. A plug 96 of the pipe hanger 96 and a tree cap or top pipe hanger plug 98 are routed below the single hole finish riser 96 and installed in the pipe hanger 60 and / or tree cap 74 respectively to provide such new ones. barriers. When the integrity of the tubing hanger plug 96 and tree cap plug 98 has been verified, the LRP 80 and its associated single hole finish riser 92 are removed from the HXTYTH 70 assembly.

Referring to Figure 10, the final step in the illustrated sequence of well finishing operations is the placement of a fragment cap 71, typically using an ROV. The well is then ready for production.

When a well recovery is required to be performed using a horizontal Christmas tree to control production flow, similar steps as mentioned above are performed in a different order. Recovery can be performed to recover a defective Christmas tree or a defective pipe hanger or both. The use of deep mounting barriers allows the recovery operation to be conducted without the need to route a BOP exhaust pipe to the well.

An example of a method of repairing an underwater well using a horizontal Christmas tree for the production flow control device according to one embodiment of the present invention is described below with reference to Figures 6 to 10 with reference numerals. similar referring to the similar parts. As described above with respect to a well finish utilizing a horizontal Christmas tree for production flow control, it should be understood that the specific sequence of steps will vary depending on the purpose of a specific recovery operation. The following description refers to the removal of the HXT / TH 70 assembly. As a first step, the debris cap 71 is removed, typically using an ROV. An LRP 80 and EDO 90 are prepared on basement floor 44. This LRP / EDC assembly is then routed in a finishing riser 92 above the horizontal Christmas tree. Surface tree 88 is commonly composed and LRP 80 is installed on top of horizontal Christmas tree 50.

The integrity of the connections between the LRP 80 and the horizontal Christmas tree 50 is verified, typically through pressure tests and other function tests. When the LRP 80 is in position, the rams and / or valves in the vertical bore of the LRP 80 meet the statutory requirement for two independently verified barriers, allowing removal of the tree cap and pipe hanger plugs 98 and 96 respectively. Typically, these plugs are recovered by wire line.

The next step is to re-establish the first deep mounting barrier 26, in this example on the first inner tube hanger 24. The integrity of the first barrier 26 is verified. The second deep mounting barrier 30 is then installed, in this example, on the second inner tube hanger 28 and its integrity is normally checked.

When the integrity of the first and second barriers 26 and 30, respectively, have been verified, the HXT / TH 70 assembly can be unlocked from wellhead 11 and recovered above water line 66. first and second barrier 26 and 30, respectively, to satisfy the statutory requirement that two independently verified barriers are in place during the recovery operation.

[00123] The required repair, maintenance or other repair work is conducted on the horizontal Christmas tree and / or pipe hanger, typically on the rig floor 46 or the basement floor 44. When the repair has been performed, the HXT assembly / TH 70 is retrofitted above waterline 66 and returned to well 10 using a procedure as described above for performing a well finish for a well using a horizontal Christmas tree for production flow control.

It should be understood that a retrieval operation may also be performed in accordance with that aspect of the present invention without removal of the horizontal Christmas tree, if desired. In this scenario, the LRP 80 and its retaining riser 92 are routed to the well as described above, allowing removal of pipe hanger plugs, tree cap and pipe hanger plugs 98 and 96, respectively. The first and second deep mounting barriers 26 and 30 are installed and verified as described above. LRP 80 is then recovered to floor 44.

To remove only the pipe hanger 60 (along with the finishing pipe 62 suspended from the pipe hanger 60), a pipe hanger routing tool (not shown) is routed to the well to unlock from from the body of the Christmas tree and recovering the pipe hanger 60 and the finishing pipe 62 leaving the horizontal Christmas tree 50 installed in the wellhead 11.

For wells using a vertical Christmas tree for production flow control, examples of finishing and / or recovery such as a well in accordance with embodiments of the invention are now described in detail below with reference to Figures 11 to 20. with similar reference numerals referring to similar parts. The well is first drilled, lined and suspended as described above with reference to Figures 3 and 4.

Referring to Figure 11, a finishing tubing 62 is composed on the tread floor 46 terminating at its highest end on a tubing hanger 60. A tubing hanger routing tool (THRT) 200 is positioned above the pipe hanger 60 is used to assist in guiding, placing, and locking the pipe hanger to wellhead 11. The THRT 200 can also be used to mount the seals between pipe hanger 60 and wellhead 11. A THRT 200 is provided with a pipe hanger guiding mechanism 202, which is configured to interface with guiding devices positioned on guide base 12. Guiding mechanism 202 may not be required when using a concentric spindle.

The pipe hanger 60 with the finishing pipe 62 suspended therefrom is routed to the well through the high seas along with the THRT 200 and pipe hanger guidance mechanisms 202. A trim riser or placement column 92 extends above THRT 200 to rig floor 46. During routing of trim tubing 62, THRT 200 and tubing hanger guidance mechanism 202, primary control of the The well is provided by at least two independently verified barriers 26 and 30. These barriers are held in position at least until finishing piping 62 is installed in wellhead 11. Having verified the orientation of piping hanger 60 relative to wellhead 11, if required, using the THRT 200 and its mechanism. In guiding direction 202, the pipe hanger 60 is placed in the wellhead 11, and locked in position. Piping hanger 60 installation in the well is verified by checking the integrity of all hydraulic and electrical connections between piping hanger 60 and wellhead 11 and / or any borehole equipment.

The THRT 200 and its associated guiding mechanism 202 and finishing riser 92 are then recovered to the rigging floor. Referring to Figure 12, a vertical Christmas tree 51 with an equivalent number of flow holes to that of the tubing hanger 60 is positioned on the basement floor 44. If required, the vertical christmas tree 51 is provided with guidance means to assist in correctly orienting the vertical christmas tree 51 with respect to the tubing hanger 60 when installed.

Referring to Figure 12, a lower riser pack (LRP) 80 is positioned above the vertical Christmas tree 51 on hold 44. The LRP 80 is provided with rams and / or valves in the vertical bore as a means of providing barriers. The LRP 80 is a unit significantly smaller than the BOP 40 exhaust pipe and thus can be routed from a smaller vessel than required to accommodate and route the BOP 40 exhaust pipe. The LRP 80 is used together. with an emergency disconnect connector (EDC) 90 to allow finisher riser 92 to be disconnected from LRP 80 if required; for example under stormy conditions.

Referring to Figure 13, the LRP 80, EDC 90 and vertical Christmas tree 51 are routed to the well and positioned in wellhead 11. A fixture riser, in this example a hole finish riser 92 The double riser extends above the EDC 90 straight to trim floor 46. Finishing riser 92 is supported and tensioned in a manner known in the art to accommodate the movement of the rig due to the state of the sea. A surface flow tree 88 is used in connection with the LRP 80 and / or Christmas tree 51 to provide pressure control during well cleaning, if desired, as well as to facilitate any transport and / or drilling operations.

Referring to Figure 14, when the vertical Christmas tree 51 is oriented, placed and locked in wellhead 11, the electrical and hydraulic connections between piping hanger 60 and / or wellhead 11 and christmas tree vertical 51 are checked. Each of the vertical christmas tree flow holes 70 is provided with at least two valves, plugs and / or lids 75 which are used to control the flow from the well during production, [00133]. lower riser package 80, surface tree assembly valves 88 and / or christmas tree valves 51 to satisfy the statutory requirement for two independently verifiable barriers. At this point, the second and first barriers, 80 and 26, respectively, are removed, typically by wire line or any other suitable recovery means, depending on the type of barrier used. The LRP 80 and EDO 90 as well as the associated finishing riser 92 are recovered to the rigging floor 46.

Referring to Figure 15, the tree cap 77 is then placed on the vertical Christmas tree 51 and the well is finished.

[00135] A method of finishing an underwater well by incorporating a pipe reel is illustrated in Figures 16-20. Pipe reels are used where downhole requirements require a large number of flow and communication paths from the pipe. vertical Christmas tree wellbore 51. When a pipe reel is used, some of the communication paths may be routed through the pipe reel rather than through the pipe hanger. It is possible to route the upper pipe reel from an alternative vessel to the type of drilling vessel required to accommodate and route a BOP exhaust pipe. In this embodiment, it is possible to route the upper pipe reel from an alternative vessel to the type of drilling vessel required to accommodate and route a BOP exhaust pipe.

The first and second barriers 26 and 30, respectively, independently verifiable, are positioned in the same manner as described in the first embodiment with reference to Figures 3 and 4. With reference to Figure 16, a reel guide base 115 A pipe line is installed above the finishing guide base 15. A pipe line 110 is then installed in the wellhead 11 of the suspended well of Figure 4. The pipe line guide base 115 can be used to assist in orienting the pipe hanger 60 relative to pipe reel 110. Alternatively, pipe reel 110 may include an indexing mechanism for this function.

Referring to Figure 17, a finishing pipe 62 is composed, terminating at its upper end in a pipe hanger 60 as described above. A THRT 200 with an associated guiding mechanism 202 is used to orient the pipe hanger 60 relative to the pipe reel 110. As an alternative, the steering mechanism 202 may be provided on the upper pipe reel 110 instead of the THRT 200 if preferred. At the conclusion of the correct orientation, the pipe hanger 60 is placed on the pipe reel 110 and locked in position. The integrity of the interfaces between the pipe hanger 60 and the pipe reel 110 is then verified. The THRT 200 is recovered to allow the installation of the vertical Christmas tree 51, [00138] Referring to Figure 18, a vertical Christmas tree 51, with an equivalent number of flow holes to the pipe hanger 60, is positioned on the basement floor 44. If required, the vertical Christmas tree 51 is provided with guidance means to assist in correctly orienting the vertical Christmas tree. 51 with respect to piping hanger 60 when installed. A lower riser (LRP) pack 80 is positioned above the vertical christmas tree 51 on hold 44. The LRP 80 is used in conjunction with an emergency disconnect connector (EDC) 90 to allow the riser to finish 92 is disconnected from the LRP 80 if necessary, for example under stormy conditions.

The LRP 80, EDC 90 and vertical Christmas tree 51 are routed to the well and positioned above the pipe reel 110. A fixture riser, in this example a double-hole finish riser 92 extends above the EDC 90 back to the rigging floor 46.

Referring to Figure 19, having installed the Christmas tree above the upper pipe reel 110 and the pipe hanger 60, the first and second barrier 26 and 30, respectively, are mounted as described below. the first mode above. Flow valves 75 of Christmas tree 51 are closed to allow removal of the bottom riser pack and the well is provided with a tree cap 77 if desired as illustrated in Figure 20.

When it is required to conduct an underwater well recovery operation using a vertical Christmas tree to control product flow, steps similar to those described above are performed in a different order. A recovery operation may be performed to recover a defective christmas tree, a defective piping hanger and / or a defective finisher piping. As a first step in a recovery operation, the first and second barriers 26 and 30, respectively, are sequentially re-established and verified to provide primary well control prior to removal of vertical Christmas tree 51 and / or pipeline hanger 60. Again, the use of the two independently verified deep mounting barriers allows the recovery operation to be conducted without the need to route a BOP exhaust pipe to the well.

A typical sequence for a well recovery operation using a vertical Christmas tree for production flow control is described below with reference to the embodiment illustrated in Figures 11 to 15. It should be considered that if the well includes a reel In tubing, the tubing reel typically remains in position at the wellhead while repair work is performed on the tubing hanger and / or the vertical Christmas tree.

For a recovery operation requiring removal of the pipe hanger 60, the tree cap 77 is removed, typically using an ROV. A lower riser (LRP) package 80, and emergency disconnect connector (EDC) 90, are prepared on hold floor 44 and routed to the well. A surface tree 88 is composed in the usual manner and the lower riser package 80 is installed on the vertical christmas tree 51. The integrity of the connections between the LRP 80 and the vertical christmas tree 51 is commonly verified, [00144 ] With the LRP 80 in position, the ram and / or valves in the vertical bore of the LRP 80 are able to meet the statutory requirement to provide two independently verifiable barriers, allowing flow valves 75 to open in the vertical flow holes of the spindle. vertical christmas 51.

The next step is to re-establish the first and second barrier 26 and 30 as described above with reference to Figure 4. When the integrity of the first barrier 26 has been verified, the second barrier 30 is installed and then checked. The vertical Christmas tree 51 can then be unlocked from the pipe hanger 60 and recovered to the rig where repair work is conducted. The pipe hanger 60 can also be unlocked and recovered to the rig for repair, maintenance or other work. repair if required.

Correction work is typically conducted on rig floor 46 or basement floor 44. When repair has been performed, pipe hanger 60 is returned and installed in wellhead 11 or pipe reel 110 of described above for well finishes. Vertical Christmas Tree 51 is also reinstalled in wellhead 11 using the procedure described above with respect to methods of performing a well finish.

Note that preferred embodiments of the present invention have been described in detail, the present invention has a number of advantages over the prior art, including the following: (a) eliminating the need to route a BOP exhaust pipe a second time during well finishing operations; (b) the ability to use a lower riser package instead of a BOP exhaust pipe during the installation of the subsea well production flow control device; (c) The ability to use only a lower riser package as opposed to a BOP exhaust pipe for salvage operations and interventions is a significant cost savings by eliminating the traditional requirement to use a drill BOP exhaust pipe. and marine riser for underwater wells; (d) The risk of debris entering the pipeline hanger is reduced as the pipeline hanger is no longer required to be installed through the hole of a BOP (marine riser pipe for underwater wells) exhaust pipe.

For wells using horizontal Christmas trees for production flow control, the methods of the present invention provide additional advantages including the following: (e) the ability to perform piping hanger installation on the body of a horizontal Christmas tree above line d 'water, which is a much easier operation than performing this operation underwater and simplifies any repair actions; (f) the ability to compose and verify all electrical and hydraulic connections and penetrations above the waterline; (g) eliminating the need to use underwater test trees for underwater wells using horizontal Christmas trees; and (h) the ability to use a lower riser pack (LRF) instead of SSTT for wells using a horizontal Christmas tree. LRP is considerably more robust and reliable and eliminates the need to resort to and interface with costly rental equipment. Several variations and modifications will be automatically suggested to those skilled in the relevant art, in addition to those already described, without departing from the inventive basic concepts. All such variations and modifications are to be considered within the scope of the present invention, the nature of which is to be determined from the foregoing description and the appended claims.

Claims (15)

A method of finishing an underwater well (10) extending from an underwater wellhead (11) comprising: coupling a finishing pipe (62) to a christmas tree (50) above the waterline ( 66); and depositing the Christmas tree (50) on the underwater wellhead (11) characterized by the fact that well control (10) is maintained using at least two independently verified deep well control barriers (26, 30), the first and second barriers being positioned below a lower end of the finishing pipe (62) when the finishing pipe is installed in the well (1), the integrity of each of the first and second barriers being checked after the respective barrier is positioned in this way, and the barriers remain in place at all times until the well is finished. Method according to claim 1, characterized in that coupling the finishing piping (62) to the Christmas tree (50) comprises installing a piping hanger (60) in a higher joint of the finishing piping ( 62) and lock the pipe hanger (60) to the Christmas tree (50). Method according to claim 2, characterized in that it further comprises: routing the Christmas tree (50), the pipe hanger (60), and the finishing pipe (62) offshore to well (10). Method according to claim 3, characterized in that it routes the Christmas tree (50), the pipe hanger (60), and the finishing pipe (62) further comprises routing the Christmas tree (50). ), the pipe hanger (60), and the finishing pipe (62) without an explosion prevention device (40). Method according to Claim 1, characterized in that the coupling of the finishing pipe (62) to the Christmas tree (50) comprises installing a pipe hanger (60) in a uppermost joint of the finishing pipe ( 62), lock the pipe hanger (60) on a pipe rack (110), and affix the pipe rack (110) to the Christmas tree (50). Method according to claim 1, characterized in that the Christmas tree (50) is a horizontal Christmas tree with a body (52), the method comprising the steps of: forming an assembly (70) through of the finishing piping (62) terminating at its upper end at and suspended from a piping hanger (60) in the body (52) of the horizontal christmas tree (50), the assembly being formed above line d water (66); and route the assembly (70) to the subsea well (10), where the pipe hanger (60) and the horizontal christmas tree (50) are above the waterline (66) during the set (74), Method according to claim 6, characterized in that the step of forming the assembly (70) further comprises the steps of depositing and locking the pipe hanger (60) in the body (52) of the Christmas tree ( 50). Method according to claim 6 or 7, characterized in that the method additionally comprises the step of checking the integrity of the finished assembly (70) above the waterline (66); Method according to claim 8, characterized in that the integrity check step comprises the step of checking the hydraulic and electrical interfaces between the pipe hanger (60) and the christmas tree body (52) ( 50). Method according to claim 8, characterized in that the integrity check step further comprises the step of checking the pressure integrity of the assembly (70). Method according to any one of claims 6 to 10, characterized in that the step of routing the assembly (70) to the wellhead (11) comprises the step of using a lower riser package ( 80). A method of finishing an underwater well (10) extending from an underwater wellhead (11) comprising: coupling a finisher pipe (62) to a pipe hanger (60) above the waterline ( 66); depositing the pipe hanger (60) into an underwater wellhead (11); and depositing a Christmas tree (50) in an underwater wellhead (11); characterized by the fact that well control (10) is maintained using at least two independently verified deeply established well control barriers (26, 30), the first and second barriers being positioned below a lower end of the finishing line. (62) When the finishing pipe is installed in the well (1), the integrity of each of the first and second barriers is checked after the respective barrier is positioned in this way, and the barriers remain in position at all times until the well it's over. Method according to claim 12, characterized in that it further comprises: engaging the pipe hanger (60) in the Christmas tree (50). Method according to claim 12 or 13, characterized in that it further comprises; engage the pipe hanger (60) on the wellhead (11). Method according to claim 12, characterized in that it further comprises depositing the pipe hanger (60) on the underwater wellhead (11) by means of a pipe reel (110) and engaging the pipe hanger. (60) in the pipe reel (110).