US 3322198 A
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May 30, 1967 w. MGHENRY SAFETY HOOD APPARATUS FOR DRILLING HEADS Filed Feb. 25, 1965 INVENTOR U.\\LLIAM MHENRY ATTORNEYS United States Patent Ofifice 3,322,198 Patented May 30, 1967 3,322,198 SAFETY HOOD APPARATUS FOR DRILLING HEADS William L. McHenry, 701 Vicnaire St, New Iberia, La. 70560 Filed Feb. 25, 1965, Ser. No. 435,246 7 Claims. (Cl. 166-81) The present invention relates generally to safety devices for use in field or off-shore well drilling and, more particularly, to safety hood apparatus for enclosing rotating assemblies such as blowout preventers and strippers of well drilling rigs to exhaust or remove leakage materials emanating therefrom.
During the past several years, the increasing use of air or gas as the drilling fluid or medium in well drilling applications has emphasized the several advantages of such drilling media over drilling fluids such as mud, water or brine, for example. Using air or gas, improvements have been realized in increased bit life, substantial decrease in drilling time, reduction in down time of drilling rigs, lower hole contamination, greater penetration rates, more rapid cutting return, straighter holes, and continuous geological formation testing, to mention but a few. Obviously, such advantages have significantly improved the overall economic picture in drilling operations.
The use of air or gas as the drilling fluid is not, however, without certain disadvantages, probably the most important and serious being the combustion hazard and the dust and cutting erosion and corrosion of drilling equipment. Rotating blowout preventers and strippers, mounted on the surface casing or pipe cemented into substructure beneath the drilling rig, have proved invaluable in reducing the dangers characterized by the aforementioned disadvantages but, because of deterioration over prolonged periods of continuous use, have been incapable of completely coping with such hazards and related problems.
In various drilling operations blowout preventers are employed, which, in their most widely used forms, comprise a rotating device combined with stripper rubber to provide a continuous seal about the elements in the drill string and to improve drilling under pressure with the conventionally used kelly and drill pipe. As an example, in a typical drilling operation for oil or gas, in which air or gas is used as the drilling medium, the drilling is performed through a substructure, including a cemented in surface casing above which the rig is disposed. Generally, one double or two single control gates are mounted on the casing with a rotating blowout preventer and stripper mounted directly above. The bottom gate includes fiat or blind rams which operate to completely close the hole when the drill pipe is removed therefrom. The upper gate includes rams having openings corresponding in size to the diameter of drill pipe employed, these rams closing to form a seal around the pipe to prevent blowout while the drill string is in the hole. The rotating blowout preventer and stripper rubber provides a seal about the kelly or drill pipe for either normal or pressure drilling operations.
Typically, the stripper rubber begins to wear or deteriorate after prolonged periods of use, as through normal wear of rubber or other elastics in a contact operation or because of interfering components, such as joint collars on the drill string, as the string is raised and/or lowered during relatively shorter periods of operations. In any event, the deterioration of the stripper rubber ultimately results in the leakage of air or gas, i.e. the drilling medium, and dust and cuttings in and around the bonnet. The most serious consequence of such leakage is present when gas is encountered when drilling with air or when gas is used as the drilling medium, creating a combustion or explosion hazard. Of less serious nature, but nevertheless of importance in the factor of operational economy, is
the consequential presence of dust cuttings and other erosive and corrosive elements suspended in the atmosphere around the equipment beneath the rig. Of the various remedial courses of action which have been proposed, such as modification in structure of the stripper or drill pipe joints, and doping of the kelly and/ or drill pipe to extent stripper rubber life, and to prevent leakage around stripper rubber, none has thus far entirely overcome the leakage of combustible gas, either when compressed gas is used or when compressed air is used, as gas pockets are frequently encountered in drilling, or the leakage of dust and cuttings.
It is, accordingly, a primary object of the present invention to provide improvements in safety devices for use in drilling operations.
Briefly, in accordance with an embodiment of the present invention, there is provided an enclosure or hood which encompasses the rotating blowout preventer and internal locking bonnet thereof, and which is vertically hinged to provide access to the interior components of the preventer and stripper for removal and replacement thereof. The lower portion of the hood is securely fastened to the lower section of the rotating head directly above the flow line. The upper portion of the hood extends above the exposed portion of the rotating assembly drive bushings or rings and has a hole diameter at that point sufficient to permit withdrawal of the preventer and stripper therefrom without removing the hood. Closing this hole are a plurality of inwardly directed overlapping flexible leaves or segments fastened to the hood and in contact with the kelly or drill pipe. A suction pump is coupled to hood and How line, via suitable conduit, to withdraw any dispersals or suspensions of gas, air, dust cuttings, and so forth, in the atmosphere confined by the hood, which have been placed there as a result of leakage about the stripper, bonnet, or other parts of the rotating assembly, and to exhaust such materials to the flow line or overflow outlet. The flexible leaves or segments operate as baflies to allow suflicient air flow into the hood for proper operation of the pump, maintaining a slight positive pressure inwardly of the hood at the leaved portion thereof.
It is, therefore, a more specific object of the present invention to provide a safety device for removing harmful suspensions and dispersals of material resulting from leakage about blowout preventers and/or stnippers to reduce the potential hazard therefrom and to extend the life of the preventers and strippers.
The above and still further objects, features and attendant advantages of the present invention will become apparent from a consideration of the following detailed description of specific embodiments thereof, especially when considered in conjunction with the accompanying drawings, in which:
FIGURE 1 is a perspective view of one embodiment of a safety chamber or enclosure in accordance with the present invention;
FIGURE 2 is a fragmentary perspective view of the enclosure of FIGURE 1 in its open position for installation;
FIGURE 3 is a sectional view of a portion of the embodiment of FIGURE 1 taken through the lines 3-3 thereof; and
FIGURE 4 is a side elevational view in phantom of the enclosure of FIGURE I mounted about a blowout preventer and stripper.
Referring now to the drawings, wherein like reference numerals refer to like components, a safety hood or enclosure exemplifying the present invention is illustrated generally at 10 in FIGURE 1. Preferably, hood 10 is fabricated of sheet metal, such as steel plate of sufiicient thickness to withstand the vibration accompanying drilling operations and rough handling in moving the rig from one location to another. The hood comprises a pair of conical frustumlike portions 12 and 14 having open ends, and arranged 'base-to-base to form a seam which may be welded or otherwise suitably fastened to secure portions 12 and 14 together. Each of the conical portions 12 and 14 has a collar 17, 19, respectively, projecting from the free end thereof to form clamping and seal arrangements as will hereinafter be described.
To adapt hood for simple and rapid installation, it is split vertically in half sections which are coupled together on one side by a hinge 28, such as a piano hinge, covered by a suitable strip of rubber or other resilient material 29 which may be cemented along the portions of the hood flanking the hinge to accommodate non-obstructed opening of the hood. On the other side of the hood, the split portions are each provided with a flange 22, 23 running the length of the split, each flange having corresponding holes (not shown) to permit the insertion of suitable fasteners 30, such as bolts, for securely closing the hood. In addition, a rubber strip 26 may be provided along the interior surface of one or both flanges 22, 23 to maintain a suitable seal when the hood 10 is closed and fastened. Collar 19 may also have a ring of flexible material, such as rubber, extending circumferentially about the interior surface thereof to form a seal at that point when the hood is clamped shut.
Collar 17 has positioned thereabout a plurality of wedge-shaped leaves or segments 35, of rubber for example which may be clamped or otherwise suitably fastened to the interior surface thereof, slightly below its upper lip 40. Leaves or segments 35 are arranged circumferentially about the inner surface of collar 17 in overlapping fashion, as is shown more clearly in FIGURE 3. The overlapping leaves form a central hole 38 through which the drill string is to extend. Thus, leaves 35, which form baffles, are placed in contacting engagement with the kelly or drill pipe when hood 10 is mounted in position, while still permitting sufficient air flow when a partial vacuum is created within the hood 10, by apparatus to be described, after it has been installed. Moreover, since segments 35 are flexible they will also permit removal of the blowout preventer and stripper combination from the outlet body, if desired, without requiring the removal of the hood. In an alternative embodiment, the hood is permanently fastened, as by welding the lower end 19 thereof to the manifold body, and only the upper conical portion 12 is provided with a suitable hinged door for access to and replacement of rotating assembly parts. 7 A duct 44, such as a three to four inch metal pipe or flexible hose, is coupled to the hood 10 to provide an outlet therefrom for leakage material accumulating in and about the interior region of the hood.
Referring now to FIGURE 4, safety hood 10 is illustrated in phantom in its installed position about the rotating assembly mounted above the surface casing (not shown) in the substructure beneath the drill rig. Specific details of rotary drilling heads and blowout preventers and strippers, about which the safety hood of the present invention is to be mounted, are well known in the art, and since they form no part of the present invention except insofar as may be necessary to determine dimensions in a specific detailed construction, need not be further discussed. It is sufficient to note that the blowout preventer generally indicated at 50, combined with stripper (not shown) is fastened by a bonnet 52 to outlet pipe body 55 and locked thereby into position. The upper collar 17 of hood 10 extends above the drive bushings 51 of the preventer and the kelly or drill pipe 60 extends through the central hole defined by the flexible leaves 35.
A suction pump 67, comprising for example a 12-inch suction-type blower fan, powered directly by any suitable commercially available spark proof motor of approximately one-half horsepower, and ample to exhaust leakage materials from within hood 10, is coupled to the interior of the hood through a short flanged nipple section via pipe or hose 44, and to flow pipe via a short hose section coupled to pipe or hose 75. The suction pump may be mounted on plate 70 supported by struts 72, appropriately attached to the exterior surface of the hood, although other supporting structure may be employed. As previously discussed, the suction pump, when in operation, diverts the leakage materials from the interior of the hood to flow pipe 80, creating a slight positive pressure on the flexible leaves 35 as air flows into the hood. Obviously hood 10 need not be otherwise leak proof since a slight positive pressure will also be created toward the interior of the hood through any inadequately sealed portions thereof.
The present invention provides a simple, convenient and inexpensive apparatus, having no moving parts at the mounting points, to divert dangerous dispersals of gas, dust, cuttings and the like which may leak through faulty sections of the stripper rubber or portions of the blowout preventer.
While I have described one specific embodiment of the present invention, it will be apparent that various changes and modifications in the specific details of construction and operation may be resorted to without departing from the 'true spirit and scope of the invention. It is, therefore, de-
sired that the present invention be limited only by the appended claims.
1. A safety device for enclosing the blowout preventer in the drilling head of well drilling apparatus and for removing particles escaping into the atmosphere from said drilling head, said device comprising a split closable hood adapted to be mounted on said drilling head; said hood having a pair of open end portions; one of said end portions including means for clamping said hood in substantially sealed relation about a portion of said head; the other of said end portions including a collar, a flexible baflle inwardly directed from the interior surface of said collar, said baffle having a hole therein for accepting the drill string of said well drilling apparatus and for permitting entry of air into said hood; and means for withdrawing said air and said particles from the interior of said hood for controlled disposal thereof.
2. The combination according to claim 1 wherein said baffle includes a plurality of flexible wedge-shaped overlapping leaves fastened about the interior of said collar.
3. The combination according to claim 1 wherein said means for withdrawing includes an outlet pipe and a vacuum pump coupled to said outlet pipe.
4. Apparatus for removing leakage material suspensions from a region proximate the drilling head of well drilling equipment, said apparatus comprising a substantially rigid sheet of material defining a chamber for enclosing said region, said chamber having an end portion conforming in shape to a portion of said drilling head and arranged to be fastened thereabout, said chamber having a further end portion arranged for contacting engagement with the drill string of said well drilling equipment, means for permitting ingress of controlled quantities of air into said chamber, and means for withdrawing air and said leakage material suspensions from said chamber.
5. The combination according to claim 4 wherein said further end portion includes a plurality of inwardly directed flexible segments fastened about the interior periphery thereof, said segments forming said means for permitting ingress of controlled quantities of air.
6. The combination according to claim 5 wherein said means for withdrawing includes an outlet duct and suction pump means coupled to said outlet duct for extracting said air and leakage material suspensions from said chamber.
7. The combination according to claim 6 wherein said rigid sheet is split and hinged along at least a portion thereof to provide a closable opening for access to component parts of said drilling head without removal of said chamber from said head.
(References on following page) References Cited 5 ,8 4/1953 Allemang UNITED STATES PATENTS 3,202,218
166-81 8/1965 Watts 166 .5 865398 9/1907 Cook CHARLES E. OCONNELL, Primary Examiner. 1,418,612 6/1922 Beard 166-81 5 2,514,817 7/1950 Wheaton 15 210 N C. BYbRS, Asslsmm Examlne).