Blowout Guillotine

Abstract

A hinged housing can be opened and then closed around a well casing with a tight seal. A rotary cutter disc is slidably mounted in the housing and operates to cut through the well casing within the housing and to polish the upper end of that part of the severed casing extending into the well. Hydraulic means are then actuated to press a face of the cutter disc against the polished end of the casing to positively close and seal the well.

Description

BACKGROUND OF THE INVENTION

This invention is in the field of devices for cutting through well casings and sealing the well.

In many instances, oil and/or gas wells develop extreme pressures, or for some other reason control valves and structures at the surface of the ground are destroyed or damaged resulting in uncontrollable loss of well fluid, and in some instances, the flowing fluids are ignited and the well burns out of control. Many proposals have been made heretofore for capping or shutting off flow from such blown out or burning wells but none have proven completely successful. It has been proposed to clamp a multipart housing around a well casing above the ground surface and by means of devices within the housing to collapse and flatten the casing at some point therein to shut off flow from the well and then to perforate the casing below the closure and withdraw well fluids from the housing. Such a proposal is shown in U.S. Pat. No. 1,949,672. Another proposal has been to bolt or otherwise secure a multipart housing around a well casing and shearing knives within the housing are operated by hydraulic means or otherwise to shear through the casing within the housing, the shearing knives themselves then serving as a gate valve to close the well. Such a proposal is shown in U.S. PAT. No. 1,875,673 . Such proposals, however, have not been successful since the shearing knives do not make a smooth cut and a satisfactory seal between the knives and casing has not been achieved. Other proposals for closing blown out or burning wells involved the provision, as a permanent part of the well casing, certain valvelike devices for shutting off flow.

SUMMARY OF THE INVENTION

The present invention relates to a device comprising a hinged housing that may be applied to and locked around an unprepared exterior portion of a well casing, between casing joints, in tight clamping and sealing relation thereto without modifying the well casing itself. A rotary cutter within the housing is arranged to be moved to and across the casing therein to completely sever the same and hydraulic means on the housing can then be operated to positively press the cutting disc against the severed end of that portion of the casing extending into the well to positively close and seal the casing against loss of well fluids or pressure. Preferably, the cutting disc is provided with means for polishing the upper end surface of the severed casing to provide a perfect seal and the face of the cutting disc adapted to sealingly engage that polished surface is preferably provided with a surface layer of softer material, such as bronze.

The device is so constructed that it can be applied to a well casing while a well is in normal operation as a standby safety device or it can be manipulated from a remote position to and around a well casing in a well that has already blown or which is on fire. After the device has been manipulated in the manner set forth above to seal or close flow from the well, the upper end of the casing above the device can be capped and the cutter blade then withdrawn laterally of the casing, whereupon concrete or other material may be injected into the casing to shut the well down and the device may be readily removed for use at some other location. Preferably, all parts of the apparatus that require manipulation or movement are controlled by remotely positioned control means, whereupon the operator or operators may remain at a safe distance from the well on which the apparatus is to be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of a first embodiment of the invention;

FIG. 2 is a vertical sectional view, taken along the line 2--2 of FIG. 1;

FIG. 3 is a detailed vertical sectional view of a cutting disc in sealing relation to a pipe casing;

FIG. 4 is a schematic plan view of a second embodiment of the invention; and

FIG. 5 is a side elevational view of the embodiment of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1-3, numeral 2 indicates a casing extending upwardly out of an oil or gas well, although it may be a drill string or any other conduit extending from a well. The portion of the casing illustrated is shown as being above the surface of the ground, although the apparatus is equally adaptable to use with casings that are under water, as will be obvious.

The apparatus comprises a housing generally indicated at 4 and comprising a first portion 6 hingedly connected, as at 8, to a second portion 10. The housing portion 6 is provided with an arm 12 extending outwardly of its pivot 8 and the outer end of which is pivotally connected to the piston rod 14 of a hydraulic motor device 16. The hydraulic motor device 16 may be remotely controlled, from a control panel 18, to forcibly swing the housing portion 6 relative to portion 10 to the closed position shown by full lines in FIG. 1 or to the open position shown in dotted line. The casing portions 6 and 10 are respectively provided with a first chamber portion 20 see FIG. 2 and a second chamber portion 22.

The housing portions are further provided with semicylindrical channels 24 and 26, respectively, which face each other when the housing is closed to define a cylindrical passageway through the closed housing. That passageway is so dimensioned and configured as to tightly clamp the housing 4 to the casing 2 in sealing relationship at axially spaced positions above and below the chamber portion 20. As shown in FIG. 2, adapter sleeve portions 28 are positioned in the channels 24 and 26 to accommodate the housing to the particular size of casing illustrated. It is to be understood that the channels 24 and 26 are preferably made of a diameter to accommodate the largest well casing while such adapters as shown at 28 may be provided in different sizes to adapt the apparatus for use with well casings of any smaller diameter. Preferably, the adapters 26 are provided with circumferential grooves or teeth not shown to effect a tight grip and efficient seal against the casing 2.

The housing portion 10 is provided with the chamber portion 22 considerably larger than the chamber portion 20 and in which a slidable carriage 30 is mounted for sliding movement toward and from the casing 2.

When the carriage 30 is in its extreme right hand position, as shown in FIG. 2, it is sufficiently far from the well casing that a cutting disc 32 mounted thereon is clear and free of the casing 2 and does not extend into the passageway defined by channels 24 and 26. The cutting disc 32 is carried by a shaft 34 journaled in the carriage 30 and has a gear 36 fixed thereon. A second gear 38 is fixed to a drive shaft 40 that extends outwardly of the casing portion 10 in a direction paralleled to the direction of sliding movement of carriage 30. Fixed to carriage 30 is a pusher tube 42 which extends slidably outwardly through the rear wall of housing portion 10 through a bearing boss 44. Thus, the pusher tube 42 may be caused to slide to the right or left, as seen in FIG. 2, to produce a corresponding movement of the carriage 30. As shown, the drive shaft 40 extends outwardly through the pusher tube 42. Referring to FIG. 1, drive motor 42, preferably driving through a suitable gear box indicated at 48, is drivingly connected to the shaft 40 and is mounted on the outer end of the pusher tube 42. Thus, operation of the motor 46 causes drive shaft 40 to rotate and that shaft, through gears 36 and 38, causes cutter disc 32 to rotate. Clearly, the pusher tube and shaft 40 may be simultaneously moved with the carriage 30 toward and from the casing 2.

As shown in greater detail in FIG. 3, the cutter disc 32 is provided on its outer periphery with a plurality of cutting teeth 50. Those teeth may be an integral part of the cutter disc or may be teeth separately applied thereto but are necessarily of sufficient hardness to cut through the material of casing 2. on its lower face and adjacent the peripheral cutting teeth 50, the disc 32 is provided with polishing means 52. The polishing means may be in the nature of fine cutting teeth or may be in the nature of abrasive material secured to the lower face of the disc 32. Thus, as the teeth 50 through the casing 2, while the carriage 30 is moving to the left, as seen in FIG. 2, the polishing means 52 function to polish the upper cut surface 54 of the casing 2 below the cutter. As shown in FIG. 3, the cutting disc 32 may be made of steel or the like but is preferably provided with an inset disc 56 softer than the casing 2 and which may be of bronze or similar material. The dimensions of the cutting disc 32 and inlaid disc 56 are such that the carriage 30 may be moved to the left in chamber portion 22 sufficiently to project one side of the disc 32 completely across the end of the casing 2 and into the chamber portion 20 a sufficient distance so that an edge portion of the inlaid disc 56 overlies the entire end surface 54 of the casing 2. The inlaid disc 56, when made of bronze, functions during the cutting of the casing as an antifriction means to render the disc 32 somewhat easier to rotate and eliminates overheating of that disc. After the casing 2 has been severed and the cutting disc is in the position illustrated in FIG. 3, the motor 46 may be stopped to bring disc 32 to a standstill whereupon suitable control means at control panel 18 may be manipulated to apply hydraulic pressure to a plurality of hydraulic rams 58 carried by the portions 6 and 10 of the housing 4. Hydraulic rams 58 include piston rods 60 extending downwardly therefrom but normally held upwardly clear of the upper surface of cutting disc 32. When the cutting of the casing is completed and the cutter disc brought to a standstill, the application of hydraulic pressure to the rams 58 causes their piston rods 60 to move downwardly and apply pressure to the disc 32, thus forcing the inlaid disc 56 tightly against the polished surface 54 and thus effectively and completely sealing off well pressure within the casing 2.

The chamber portions 20 and 22 of the housing 42 are preferably completely closed to prevent loss of fluid pressure while the disc 32 is cutting through the casing 2 and before hydraulic sealing pressure is applied. In some instances, the well pressure may be sufficiently high to cause damage to the cutter mechanism, so there is provided a vent pipe 62 controlled by a valve 64 which may be opened to relieve fluid pressure from the chamber while controlling the loss of well fluids by that route.

In the modification shown in FIG. 1, the hydraulic motor 16 may apply sufficient pressure to the housing portion 6 to hold the same firmly against the housing portion 10. The hydraulic motor 16 is mounted on the housing portion 10 by suitable bracket means, in FIG. l. However, it is also contemplated that a further locking and clamping mechanism be provided. As shown in FIG. 1, a rotary rod 66 is journaled in suitable brackets 68 on housing portion 10 and extends through ears 70 on housing portion 10. A collar 72 on the rod 66 bears against a rearwardly facing surface of one of the ears 70. The rod 66 extends forwardly through the ears 70 and its outer end is threaded as at 74 and is adapted to enter a threaded portion of an ear 76 carried by the housing portion 6. Thus, when the housing portion 6 is swung toward its closed position sufficiently far to engage the threaded end 74 with the threads in ear 76, the rod 66 may be rotated to forcibly draw the housing portions 6 and 10 together in tight sealing and firmly clamped relation.

The modification shown in FIG. 4 functions substantially identically to that shown in FIGS. 1-3 but different means are employed for clamping the housing portions together. In FIGS. 4 and 5, all portions identical to those of FIGS. 1-3 bear the same reference numerals and many details are omitted for clarity of illustration. In this form of the invention a plurality of hydraulic motors 78 are mounted on the housing portion 10 and loops or bails 80 are pivotally connected to the outer ends of piston rods 82 extending rearwardly from the hydraulic motors 78. The housing portion 6 is provided with ears 84 defining seats for the forward ends of the loops 80. Thus, to lock the housing portions together the loops 80 may be moved to the position shown, inwardly of ears 84, and the application of hydraulic pressure into the left-hand of the motors 78 will cause the loops 80 to apply sufficient clamping and sealing pressure to the housing sections to maintain the apparatus in fixed position on the casing 2. In all other respects the modification shown in FIGS. 4 and 5 may be identical to those already described with reference to FIGS. 1-3.

Either form of the apparatus may be applied to an accessible portion of a well casing 2 during normal operation of the well, as a safety feature to be employed only in the event of blowout or fire. On the other hand, the apparatus described may be applied to the casing 2 only after a well has blown out or caught fire. In such instance, it is essential that all operations be capable of being controlled from a remote and safe position. Any suitable guide means can be provided for guiding the housing 4 toward the well casing 2 from a remote position. Such means may take the form of trackways projected from the remote position toward the well casing. The closing of the housing about the well casing and all of the described operating functions may then be controlled from a position of safety remote from the well without endangering operating personnel.

While a limited number of specific embodiments of the invention are shown and described herein, the same are merely illustrative of principles involved and other forms may be employed within the scope of the invention.

Claims

I claim:

1. A device for cutting through and sealing an oil well casing, comprising:

a housing having complementary, relatively movable portions adapted to embrace and sealingly engage and clamp around an oil well casing at axially spaced positions;

a chamber in said housing, a first portion of which surrounds said casing between said spaced positions;

a rotary cutter disc, having a cutting edge, rotatably mounted in a second portion of said chamber and mounted for movement to project a portion of the same into said first portion to thereby sever said casing and position said disc across a severed end thereof;

selectively operable means carried by said housing for forcibly pressing one face of said disc against said severed end of said casing to seal the same; and

drive means for rotating said cutter disc, and separate means for moving said disc to project its said portion into said first portion of said chamber .

2. A device as defined in claim 1 wherein said relatively movable portions of said housing comprise a pair of complementary portions hingedly connected together, means for hingedly swinging said complementary portions between open and closed positions, and selectively operable means for locking said complementary portions in closed position about said casing.

3. A device as defined in claim 1 wherein said pressing means comprises at least one hydraulic ram device and remotely located control means for said hydraulic ram device.

4. A device as defined in claim 1 wherein said disc is provided with cutting means on its periphery for severing said casing, and polishing means on said one face adjacent said periphery for polishing the severed end of said casing.

5. A device as defined in claim 4 wherein said one face of said disc, radially inwardly of said polishing means, comprises a facing material softer than the material of said casing.

6. A device as defined in claim 5 wherein said facing material is bronze.

7. A device as defined in claim 1 wherein said cutter disc is rotatably mounted on a carriage, slidable in said second portion of said chamber toward and from said first portion.

8. A device as defined in claim 7 wherein said chamber is a closed chamber in said housing, said drive means comprising a drive shaft extending rotatably and slidably outwardly of said housing substantially parallel to the direction of movement of said carriage, said separate means comprising an elongated member connected at one end to said carriage and extending outwardly of said housing parallel to said drive shaft.

9. A device as defined in claim 8 wherein said separate means comprises a tubular member, said drive shaft extending through said tubular member.