DE2031301A1 - Device for maintenance of the lower part of boreholes - Google Patents

Description

9Λ.ΤΛ HIiHWAM

ing. B. HOLZEB

AUGSBURG

TBLMVOH ■ ItBT *

W.487

Augsburg, June 24, 1970

Westinghouse Electric Corporation, 3 Gateway Center, Pittsburgh, Pennsylvania, V.St.A.

Device for maintaining the lower part of boreholes

The invention relates to a device for maintaining the lower part of boreholes, which is used for Carrying out a cable operation can be coupled to a wellhead part and which during maintenance of the lower part of oil wells

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is used, for example during dewaxing, when removing sand, when inserting Pressure recording devices or when inserting and removing well safety valves in the lower part of the borehole etc.

In one known method for performing this maintenance, one is turned off a wire rope and a lubrication device used unit consisting of a tool is continuously or temporarily introduced into the riser pipe arranged in the borehole, by attaching it to the end of a steel wire rope which is passed through a lubricating device Housing is lowered through. A lubricator of conventional design is one of a kind Motor coupled to an externally driven winch assembly, which latter housed in a separate housing and via a combination of stuffing boxes and Sheaves are coupled in such a way that the lubrication device is subject to the pressure prevailing in the upper part of the borehole is exposed, while the housing containing the motor assembly is only exposed to the external environment sealed or, in some cases, open to the atmosphere.

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In a preferred method of security locking a submarine borehole in certain emergencies becomes a remote-controlled one located below the surface of the water Safety valve used, which is in the production riser pipe a few tens of meters from the mudline of the seabed is arranged. Valve types are available for increasing the reliability of such valves available for periodic, preventive maintenance can be removed through the riser pipe. The valve can be installed at a shallow depth easier access and less costly Maintenance. The valve is located above the underwater Wellhead part controlled by hydraulic pressure and it closes in the event of a fault above the valve on the wellhead part equipment or subsea flow line automatically and thus protects against uncontrolled leakage of conveyed material from the well.

A reliable working of the under the water surface The safety valve located is closed and reopened at regular intervals and by periodic removal and reinstallation of the valve achieved. This valve is remotely controlled by means of a hydraulic system housed in a removable wellhead subassembly. The Aue

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BATH ORIGINAL

and reinstallation of this valve is carried out by means of a device for maintaining the lower part of boreholes, which from time to time at the top of the wellhead part! is attached. The safety valve, designed as a ball valve, is inside a cylindrical Sheath arrangement attached and held in a special pipe nipple by means of a mandrel. Such, Devices used in the installation and removal of valves generate the relatively large axial forces that are necessary for use the valves and removing them after a long period of operation. To generate this large forces an arrangement of rope operated tools is used for the lower part of boreholes *, The tools each have an adapter that acts on the running or pulling * the tool, a hydraulic tank, a heavy drum, an accelerator, a hydraulic piston and an adapter for attachment to the rope drum exhibit.

The invention is intended to solve the problem, a Device for maintaining the lower part of boreholes of this type to improve that it has a simple structure is reliable works and prevents leakage flows from the lower part of the borehole.

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In order to achieve this object, the invention includes a device for maintaining the lower part of Boreholes, which are used to carry out a rope operation can be coupled to a wellhead part and which is characterized according to the invention in that with a pressure vessel is coupled to the wellhead part, in its interior after opening the borehole head part and the establishment of access to the relevant borehole, the borehole head part pressure prevails, wherein the pressure vessel a drive motor coupled to a winch drum and a direct motor wound onto the winch drum has wire rope connected to the maintenance tool, and that finally devices such with the pressure vessel and the drive motor are connected so that the latter are operated from a remote control station can.

The device according to the invention for maintaining the bottom of the borehole, which is suitable for use at the Earth's surface and below sea level Suitable for boreholes, the use of stuffing boxes or pressure seals is superfluous.

As an example, the invention is described in more detail below with reference to a preferred embodiment, which is illustrated in the drawings, the show in detail:

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Fig. 1 in side elevation and partly in

Section a preferred embodiment of an inventive Device,

Pig. 2 a typical downhole tool

arrangement, which is used in the device according to the invention,

3 shows an enlarged longitudinal section

of the upper part of the in Pig. I illustrated embodiment of the Invention,

Fig. 4 shows a cross section below the

upper housing cover of the part shown in Fig. 3., and

Fig. 5 is a partial view of a lift

housing, which at. the embodiment shown in FIG of the invention is used.

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In Pig.1 of the drawings there is shown an assembled pressure vessel which is internally pressurizable with the pressure prevailing in a borehole drilled deep into the earth from land or sea. Although the preferred embodiment of the device according to the invention is not is limited to this, however, it is described with reference to a pressure vessel which can be coupled to a submarine borehole by means of a wire, rope. Reference numeral 10 denotes a subsea wellhead subassembly which includes a wellhead sub housing 12 and a valve assembly Ik connected to a production tubing string 16. A re-entry connection assembly, which has a collar 18, is located on top of the wellhead subassembly 10 so that the lower part of the wellbore is accessible.A long tubular casing 20 for a downhole tool comprises a thick-walled steel pipe, the inner diameter of which is appropriate to the diameter of the production tubing string and its Length depends on the desired functions. This tubular housing is provided at the upper end with a collar 22, by means of which it can be coupled to a collar 2k adapted to this collar at the lower end of a motor and winch housing by means of a split clamping fixture 28

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is. At the lower end of the tubular housing 20 is a Formed collar 30, which is similar to the upper collar 22 and which with a collar adapted to this collar a valve assembly 34 which has, inter alia, a drain valve 36. A split clamp attachment 38 connects the collars 30 and 32 to one another. The lower part of the drain valve 36 ends in one Bund 40, which with a collar 42 on a separation valve cooperates. The connection between these two collars is produced by a split clamping connection 46. A check valve is provided by means of a split clamping connection 52 which connects collars 54 and 56 to one another 50 coupled to the isolation valve 44. The lower part of the check valve 50 ends in one Collar 58, which by means of a split clamp connection 62 with a hydraulically actuated wellbore top connection arrangement 60 is coupled. The wellhead connection assembly 60 is used for attachment of the re-entry collar l8 at the top of the valve arrangement 14 and is also used for supply or Unlocking the connection arrangement and to check the seals of the connection arrangement with hydraulic lines (not shown) provided.

The tubular housing 20 contains a wellbore maintenance

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Tool assembly 64. A typical tool assembly is shown schematically in Figure 2 and has, for example, a ball-and-tube safety valve 66, a mandrel 68, a running or pulling tool 70, a tool connection adapter 72, a hydraulic vibrator assembly 74, a weight rod 76, a nitrogen-operated one Rüttelbeschleuhiger 78 and a rope connector 80. All of these items are the best for a specialist known and are dimensioned such that they through the tubular housing 20 and through the valve assembly 34 over the valve assembly 14 is lowered into the riser pipe l6 can be

In addition, the downhole tool casing 20 is coupled to a plurality of hydraulic lines 82 which are used to actuate valves 36, 44 and 50 of a controlled vessel (not shown) are required. The hydraulic lines are with a socket support plate 84 coupled, which is attached to the motor and winch housing 26 and a plurality of with Has internally threaded hydraulic coupling parts 86. The valves of the valve assembly 14 can either independently of each other or, if necessary, through additional, connected to the socket support plate

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Hydraulic lines are operated

When the tool assembly 64 is in a position within the housing 20 and above the drain valve 36 is brought, the isolation valve 44 is kept closed. The part located above the separating valve 44 of the housing 20 is filled with hydraulic fluid after the tool assembly 64 before it is in brought the proximity of the wellhead subassembly 10 is, has been introduced into the housing · The isolation valve 44 prevents this fluid from before the Put on the embodiment shown in FIG. 1 the invention on the Bohrloehkopffteilfaaueinfoeit 10 get lost. When the arrangement shown in FIG is attached to the wellhead subassembly 10 the vent valve 50 opens, thereby forming a hydraulic lock in the riser bore is prevented · This valve is also after the end of an operation in which the tool assembly tion 64 in the riser is moved, opened when the valves of the valve assembly 14 and the isolation valve are closed, so that the pressure of the trapped in the riser part between these two valves Fluid is drained. An opening of the separating

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valve 44 causes not only the tool housing 20, but also the motor and winch housing 26 in the Borehole is exposed to prevailing pressure · When the Tool assembly 64 is removed from the riser 1.6, the isolation valve 44 is closed and the drain valve opened, so that both the pressure inside the tool housing 20 and the winch housing 26 and the mixture drained from hydraulic fluid, production fluid and seawater. This arrangement is shown as an example only because, depending on the special application and a permissible draining of the fluid in the tool housing 20 can the number of valves required can be reduced.

Since one of the objects of the invention is instead of using a storm flap to open the lower part of the Borehole to attach a safety ball valve, the tool assembly 64 must be designed so that they to can be lowered approximately 60 m below the wellhead subassembly 10. A motorized cable winch arrangement in the winch housing 26 and coupled to the cable connector 80.

As shown in FIGS. 3 and 4, which

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Sectional views of the latter arrangement 'show, a winch drum 88, a wire rope 90 wound thereon and a hydraulic drive motor 92 are arranged within the winch housing 26 on a frame 93, the winch housing 26 directly with it. connected to the tool housing is · Accordingly, the winding mechanism 88, the motor and the cable 90, rather than being exposed to the seawater or enclosed in a separate pressure vessel exposed to W directly the pressure and fluid environment of the downhole tubing string sixteenth

Since the winch housing 26 is exposed to the wellbore pressure lying cm in the order of 365 kp /, it has according to the representation in Fig. ¹ I cylindrical surfaces, so that it can withstand these pressures · The housing consists of Legierungsstahlguß and has the shape of an eccentric Reduzierrohrfittings at whose end provided with the smaller clear width the collar is arranged, which is connected to the collar 22 at the top of the tool housing 20 The upper end of the winch housing 26 forms a common part with a collar 9k, which forms a seat for a Housing cover forms · The cover 96 is attached by means of a split clamp fastening 98 and a sealing ring 99

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attached to the collar 94.

The winch drum 88 is on or on a radial piston motor housing 100 attached. A shaft 102 is by means of a bolted clamp mounting arrangement attached to the frame 93 and thus locked against rotation. By securing the shaft against rotation the motor housing rotates around the stationary shaft. A hydraulic supply line 106 conducts hydraulic fluid via channels (not shown) formed in the shaft 102 to the engine pistons (not shown), while a return line 108 provides hydraulic fluid discharges from the engine. Yet another hydraulic line 110 is used as a motor housing drain. By Attaching the motor housing 100 to the inner periphery of the winch drum 88 is the hydraulic motor 92 in FIG Able to drive the winch drum directly, i.e. without using a clutch. The winch drum is from bearings arranged inside the motor housing itself. A channel adapter (not shown) on one End of stationary shaft 102 is used to reverse the direction of rotation by changing the direction of flow of the Hydraulic fluid in the inlet and outlet

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lines 106 and 108 is reversed.

The wire cable 90 is coupled to the cable connector 80 of the tool arrangement 6k via a guide part 112. Since the borehole pressure prevails inside the winch housing 26 and the tool housing 20 and since no stuffing boxes are required, the wire rope 90 can be either a solid wire, a stranded cable or a flat steel band, depending on the application. A flat steel band can therefore be used because no seal is required at the point where the steel band has to be passed through. Another advantage of the flat steel strip is that it aligns itself with respect to the guide part 112, so that no layer winding device required for evenly winding a wire rope or cable onto the winch drum 88 is required.

The preferred embodiment of the invention is by means of a maintenance device, for example by means of a retractable vehicle guided on a tether or by means of a remote control device (not shown), which is used for carrying out maintenance

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work is designed, attached to the top of the wellhead sub-assembly 10 or removed from there. The hydraulic control of the attachment process, operation and removal of the device according to the invention takes place from the maintenance arrangement, which also has the hydraulic energy source and the control valves required for remote control of the valve arrangement 3Ί and the hydraulic drive motor 92. The hydraulic energy is transferred from the maintenance arrangement to the socket support plate 8 * 1 by means of a suitable hydraulic line system and by means of an externally threaded multiple line connector which connects to the internally threaded coupling parts 86. The sleeve support plate 8 ¹ J has a steel bracket which is welded to the body of the winch housing in the vicinity of the upper end of the tool housing 20.

The air weight is considerably large in the preferred embodiment of the invention. To make things easier · the attachment and removal of the one shown in FIG Embodiment of the invention on or from the wellhead subassembly 10 By means of a maintenance arrangement, it is necessary that the overall arrangement

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is neutrally buoyant after immersion in water . This is achieved either by means of a buoyancy housing 114 shown in FIG. 5 or by means of a buoyancy chamber 116 shown in FIG. 1. The buoyancy housing 114 is filled with cast blocks 118 made of synthetic foam, which has a lower specific weight than water. The center of buoyancy of this floating material must be above the center of gravity of the submerged steel material of the overall arrangement. For this reason, the synthetic foam blocks 118 must be arranged symmetrically around the upper part of the tool housing 20. The buoyancy housing 114 is particularly suitable for working in great water depth, ie in water depths of 300 m and more.

If the water depth is less than 500 m, the Buoyancy chamber assembly 116 preferred. This is designed as an airtight vessel, which absorbs the external pressure which is equal to the column of water, which can produce a differential pressure of about 31.3 kp / cm. Accordingly, a cylinder jacket can be used, which is each hemispherical at its ends

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Upper parts 120 is provided. In addition, the axis falls the chamber with the axis of the device housing 20 in the Sewing the upper part of the overall arrangement together In order to reduce the weight and costs of the buoyancy chamber, the chamber must also be preloaded compressed gas possible is precharged to a pressure of about 15.8 kgf / cm, the external water pressure is approximately equal to the internal pressure and there is thus no differential pressure in the area of the jacket of the buoyancy chamber. In a water depth of 300 m, the external pressure exceeds the internal pressure

ρ ■ '■■■.'

about 15 »5 kp / cm, so that the construction of the buoyancy chamber 116 with regard to this residual differential pressure can be carried out, which results in a weight and cost saving.

The versatility of the preferred embodiment of the invention results directly from the fact that the the same arrangement can be used either on land or under water, in the former case only the buoyancy housing or the buoyancy chamber is omitted. It should be noted, however, that this arrangement of the

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it

Invention due to the weight of the additional high pressure part and because of the increased risk due to the larger volumes under pressure on land, not has the same advantages as underwater. The device according to the invention can, however, according to the Functions that it has to fulfill can be changed by simply changing structural details · For example must be required depending on the depths to be reached in certain P Forces the rope strength, the drum diameter, the motor power and the size of the pressure housing necessarily can be changed selectively. In addition, the size of the vertical tool housing depends on the length of the tool assembly required and the diameter of the well tubing into which this should be introduced.

^ The embodiment of the invention described above

thus provides an improved apparatus for the maintenance of the lower part of those located on land or under water Wells represent in which a composite, a wire rope assembly having vessel at downhole pressure is operable that not only the wire rope device arrangement,

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but also contains the winch and drive motor, whereby no wire rope seals are required.

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Claims (6)

Claims; 1. Device for the maintenance of the lower part of boreholes, which is used to carry out a rope operation Can be coupled to a borehole head part, characterized in that a pressure vessel (26) is coupled to the borehole head part (10), inside it after opening the wellhead part and the establishment of an access the borehole head part pressure for the borehole in question prevails, the pressure vessel having a drive motor (92) coupled to a winch drum (88) and a Wire rope (90) wound onto the winch drum and directly connected to a maintenance tool (64) and that finally means (84, 86) are so connected to the pressure vessel and the drive motor, the latter from a remote control station can be operated from. 2. Device according to claim 1, characterized in that that the winch drum (88) is arranged around the housing (100) of the motor (92) and with the motor housing is rotatable together, the motor shaft (102) being locked against rotation and thereby causing - 20 - 009884/1513 the motor housing rotates when the motor is running. 3. Apparatus according to claim 1 or 2, characterized in that the winch drum drive motor (92) is a Radial piston hydraulic motor is. 4. Device naeh one of claims 1 to 3 * dfäge characterized in that instead of the wire rope (90) a flat metal band of a certain length is provided, which is wound onto the winch drum (88). 5 · Device according to one of claims 1 to 3 »thereby characterized in that instead of the wire rope, a stranded cable is provided which is attached to the rope drum (88) is wound up. 6. Device according to one of claims 1 to 5 # characterized by a buoyancy device (116) which is attached to the pressure vessel (26) and ensures that the maintenance device arrangement is floating in water is. 7 * device according to claim 6, characterized in that that the buoyancy device (116) has a housing (Il4) having which axially around the pressure vessel (26) is arranged and contains buoyant material (118). - 21 0098 8 4/1513 Lee on the side