US 3032125 A
Description (OCR text may contain errors)
Y 1962 w. F. HISER ET AL 3,032,125
OFFSHORE APPARATUS Filed July 10, 1957 TELESCOPIC JOINT INVENTORS.
SHILE D- McCARTY, WILBER F.HISER,
ATTORNEY- United States hatent Ufliice 3,032,125 Patented May 1, 1962 This invention is directed to an apparatus for conducting offshore well operations. More specifically, the invention concerns an arrangement of offshore well equipment for returning circulation of drilling fluid.
Drilling operations for offshore structures, including both floating barges or platforms or permanently established structures, are at present performed with well head and blowout preventer equipment installed on the ocean floor. Hoses or conduits connected between the submerged equipment and the equipment above the surface of the water provide means for the return of drilling fluid circulation and also provide means for hydraulically operating the subsurface equipment. In such an arrangement a rotating packer or drilling head is required to provide a seal around the drill pipe in order to retain the drilling fluid in and to exclude the sea water from the drill pipe-casing annulus. Because of the remote location of the rotating packer on the ocean floor, leakage of drilling fluid to the sea water as a result of normal wear of the packer element occurs unobserved in numerous instances. When such leakage occurs, a large quantity of drilling fluid is lost. Loss of the drilling fluid in this manner results in pollution of commercial fishing areas, sticking of the drill string and loss of control of the well. The restriction of flow of the return drilling fluid through the conduit connection between the well head and the water surface structure increases the pressure necessary to provide the circulation. This not only increases leakage losses, noted supra, but in many instances causes loss of drilling fluid to low pressure formations.
The invention herein provides an improved arrangement of equipment for offshore operations whereby the rotating packer is relocated to a position above the surface of the water, in which position it can be observed while in operation. The arrangement of equipment also reduces the amount of return circulation hose required, which, in turn, reduces the pressure necessary for drilling fluid circulation.
Briefly, the invention comprises a structure provided with an operations platform arranged above the surface of the water, a submerged well head arranged adjacent the land underlying the water and a conductor pipe extending between the platform and the well head. The conductor pipe, which may include a telescopic joint, a flexible joint and an elevator, is connected to the structure above the surface of the water adjacent the upper end of the conductor pipe and is releasably connected to the well adjacent the lower end of the conductor pipe. Also the conductor pipe is provided with a fluid outlet adjacent the upper end thereof for the return drilling fluid circulation.
Thus, an object of the present invention is to provide an arrangement of offshore well apparatus adapted to facilitate well operations and especially to facilitate circulation of drilling fluid.
This and other objects of the invention will be apparent from a description of the invention taken in conjunction with the drawings wherein:
FIG. 1 is an elevational view of the submerged Well head equipment, the water surface equipment, and the conductor pipe apparatus arranged therebetween;
FIG. .2 is a view, partly in section, of an adapter pipe connected to the submerged well head equipment; and
FIG. 3 is a sectional view of the adapter employed in the embodiment of FIGS. 1 and 2.
For a clearer understanding of the operation of the invention, reference is made to FIG. 1 wherein is shown a drilling or operations platform 10 positioned above the surface of a body of water 11. The operations platform 10 may be suitably a floating barge or other floating structure, or it may comprise a permanent or semi-permanent type offshore platform installation. In any event, the platform structure 10 is provided with a well opening indicat-- ed at 12 through which the drilling or other well operations are conducted. The well opening 12 may be provided within the confines of the platform structure 10 or may be provided by a keyslot in one side thereof; or the operations may be conducted from a side of the platform 10. Positioned within the well opening 12 is shown a conductor pipe generally indicated as at 13. The conductor pipe 13 extends from the well opening 12 to the well head apparatus 14, which is positioned adjacent the land 15 underlying the body of water 11. The well head equipment is a conventional submarine assembly and may include means for supporting pipe and other suitable equipment, such as a blowout preventer 17, a pack-off 18 and a conduit connection 19 having a conduit 19 connected thereto. A casing 16 is shown connected to well head apparatus 14. The blowout preventer 17 is preferably a hydraulically operated ram type preventer. Pack-- off 18 also is preferably hydraulically operated. Such hy-.
draulic installations are conventional and desirable for submerged equipment since by suitable hose connections the equipment can be remotely operated from the struc 2 ture located above the water.
The conductor pipe 13 includes a telescopic joint 20,
sections of pipe 21, a flexible joint connection 22 and an is secured. The adapter section 23 is more clearly seen in. FIGS. 2 and 3, which figures will be described later herein. An elevator 24 is connected to one of the pipe sections 21 below the telescopic joint 20. Also, a plurality of guide arms 25 are arranged on the conductor pipe' 13 and on the well head equipment 14. Guide cables 26 are secured to the well head equipment 14, as at 27, and
extend upwardly through the various guides 25 to the drilling platform 10. Constant tension means, such as constant tension winches 30, to which the cables 26 are connected, are positioned on the platform 10. Wirelines 31 are connected to the elevator 24 at one end and are clamped to cables 26 at the other end, as at 32. A side outlet conduit or hose 33 is connected to conductor pipe 13 adjacent the upper end thereof, which end is connected to a conventional drilling head 9. The conduit 33 may be utilized for return drilling circulation, which circulation is down the rotating drillstring and up the annulus between the borehole wall and the drill string and thence up the annulus between the drill string and the wall of conductor pipe 13 to conduit 33. This latter annulus is closed off above conduit 33 by a suitable packer in the drilling head 9. Conduit 19' is adapted to extend to the platform 10 and is utilized when desired to pump fluid down the annulus between the drill string and casing 16, as for example, when it is desired to kill the well or prevent blowouts. Chains '34 connect the conductor pipe 13 to the drilling platform 10 in the well 12. While members 34 are shown and described as chains they may be suitably ropes, cables or rigid members. This connection is adapted to support and position the conductor pipe above the expanding or telescopic joint 20.
As seen more clearly in FIGS. 2 and 3, the adapter ina dicated at 23 in FIG. 1 comprises a tubular member 35, formed to provide a locking recess 36, a tapered shoulder 37 and a plurality of sealing means, which may be suitably O-rings 38. The well head assembly 14 includes a tubular housing 40 provided with a tapered shoulder 41 on the interior surface thereof and an interior surface 42 adapted to engage with the seals 38 arranged on the adapter 23. Also housing 40 is formed to provide a chamber 44. Adjacent chamber 44 a hollow member 45 is connected to housing 40. A piston 46.is arranged in chamber 44. Piston 46 has connected thereto a latch member 47, which is adapted to engage the locking recess 36 of adapter 23 when the shoulders 37 and 41 are engaged. Piston 46 has connected therto also a rod 48 which rod extends into member 45 and about which is arranged a spring 49 which is adapted to bias piston 46 in a direction which'disengages latch member 47 from engagement with the locking recess 36. Housing 40 is also provided with conduits 50 and 51, each of which conduits fluidity communicate with chamber 44 at one end and with hoses or conduits 52 and 53, respectively, at the other end. Conduits 52 and 53 connect with a source of fluid pressure at the surface of the water, not shown. Suitable seals 54 and 55 are provided to seal olf around latch member 47 and rod 48 at each end of chamber 44. A funnel guide 56 may be connected to housing 40 to facilitate proper engagement of adapter 23 and housing 48.
Thus, in operation the submerged Well head equipment 14 is positioned adjacent the bottom of the water by means of cables'26 connected as at 27 to the well head equipment 14. After the well head is in position, the conductor pipe 13 is lowered until the adapter 23, guided by funnel 56, engages with the well head equipment 14. In order to correctly and properly position the conductor pipe 13, guides 25 are slidably connected to guide cables 26 and move along the cables in the lowering process. After the adapter shoulder 37 engages the shoulder 41 of housing 40-andseals 3-8 seal off the annulus between. housing 40 and adapter 23, fluid pressure is applied through conduit 53 to chamber 44 thereby moving piston 46 to the lefthand position which inserts latch 47 in locking recess 36. During this action, conduit 52 is exhausted so that the portion of the chamber 44 on the left-hand side of piston 46 is exhausted via conduit 50.
After adapter 23 has been properly positioned and locked in the well head 14, the winches 30 are operated to vapply a constant tension to guide cables 26, which, in .turn, apply a constant tension to the wirelines 31 connected to the elevator -24. When it is desired to remove the conductor pipe 13, hydraulic pressure is applied to conduit 52 and conduit 53 is exhausted. This application of pressure to the left-hand side of piston 46 in chamher 44 moves the piston 46 to the right-hand position, which, in turn, removes latch member 47 from engagement with locking recess 36. The spring biased rod 48 connected to the right-hand side of piston 46 is employed to insure retraction of the latch member 47; that is, in case of failure of fluid pressure transmitted through conduit 52, the latch member 47 will retract anyway. Once the latch member 47 has been removed from the locking recess, the conductor pipe 13 may be removed through the well opening 12.
The adapter 23 and the connection 41 on the well head adapted to engage with the adapter is shown and described in here for purposes of illustration only. This specific adapter is described and claimed in US. application Serial No. 671,078, filed July 10, 1957, entitled Adapter, by C. M. Carothers and L. M. Harris.
Having fully described the objects, operation and elements of our invention, we claim:
1. Apparatus for conducting offshore operations comprising a floating structure having an operations platform arranged above the water level; submerged wellhead apparatus arranged adjacent the land underlying the water; a conductor pipe extending between said platform and said well-head apparatus; means for remotely releasably inter connecting said conductor pipe and said wellhead apparatus, said conductor pipe including a telescopic joint and a flexible joint and being provided with guide means and said submerged wellhead apparatus including means for supporting well pipes and also means for controlling flow of fluids through said conductor pipe; guide cables engaging said guide means and interconnecting said wellhead apparatus and said platform; cable means connected at the lower ends thereof to said conductor pipe below said telescopic joint; means connected to the upper ends of said cable means for applying a constant tension thereto to provide a constant tension support for the portion of said conductor pipe extending below said telescopic joint; and means interconnecting said platform and said conductor pipe above said telescopic joint adapted to position and support the portion of said conductor pipe above said telescopic joint.
2. Apparatus as recited in claim 1 including means connected to the upper end of said conductor pipe adapted to provide return drilling fluid circulation.
References Cited in the file of this patent UNITED STATES PATENTS Re. 24,'083 McNeill Nov. 1, 1955 1,766,628 Grant June 24, 1930 2,187,871 Voorhees Jan. 23, 1940 2,808,230 McNeill et al. Oct. 1, 1957