US3426843A

US3426843A - Marine conductor pipe assembly

Info

Publication number: US3426843A
Application number: US585645A
Authority: US
Inventors: Robert C Visser
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1966-10-10
Filing date: 1966-10-10
Publication date: 1969-02-11
Anticipated expiration: 1986-02-11

Description

Feb. 11, 1969 R. c. VISSER 3,426,843

MARINE CONDUCTOR PIPE ASSEMBLY Filed 001,. 10, 1966 Sheet 0f 4 INVENTORZ ROBERT C. V SSER HIS ATTORNEY Feb. 11, 1969 R. c. VISSER MARINE CONDUCTOR PIPE ASSEMBLY Filed Oct. 10, 1966 FIG. 2B

' INVENTOR ROBERT c. VISSER ATTORNEY FIG. 2A

Feb. 11, 1969 R. c. VISSER I 3,425,843

MARINE CONDUCTOR PIPE ASSEMBLY Filed on. 10, 1966, Sheet 5 of 4 4 n 4 560 330 4o 39 A lh e2 62 540 l FIG. 3

INVENTORZ ROBERT C. VI SSER HIS ATTORNEY Feb 11, 1969 Filed OGt. 10, 1966 F IG. 5

F l G. 6

I NVENTORI ROBERT C. VISSER BY: WW

H IS ATTORNEY United States Patent 3,426,843 MARINE CONDUCTOR PIPE ASSEMBLY Robert C. Visser, San Dimas, Califi, assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed Oct. 10, 1966, Ser. No. 585,645 US. Cl. 166-.5 Int. Cl. E21!) 43/0]; F16] 55/00 5 Claims ABSTRACT OF THE DISCLOSURE This invention relates to apparatus for use in drilling, completing and working-over operations in oil and gas wells at offshore locations. More particularly, this invention pertains to fluid conduit apparatus for the control of wellhead appurtenances located at or near the bottom of a body of water.

In an attempt to locate new oil fields, an increasing amount of well drilling has been conducted at offshore locations, such, for example, as off the coasts of Louisiana, Texas and California. As a general rule, the strings of casing in a well, together with the tubing string or strings, extend to a point above the surface of the water where they are closed in a conventional manner that is used on land wells, with a conventional wellhead assembly being attached to the top of the casing. Recently, methods and apparatus have been developed for drilling and completing wells wherein both the well casinghead, and subsequently the wellhead assembly and easing closure device, are located underwater at a depth sufiicient to allow ships to pass over them. Preferably, the casinghead and wellhead closure assemblies are located close to the ocean floor. In order to install well drilling equipment underwater at depths greater than the shallow depth at which a diver can easily operate, it has 'been necessary to design entirely new equipment for this purpose.

Wells drilled in deep water are generally drilled from vessels of varying designs commonly known as drilling barges, vessels or platforms. Deep water wells are generally drilled by one of two methods. In one method, the string of drill pipe extends downwardly from the drilling vessel to the drilling wellhead assembly, on the ocean floor, which is closed at the top :by a circulation head with a flexible hose running from the circulation head back to the surface and to the drilling vessel so that drilling fluid may be circulated down the drill pipe, through the drill bit, and thence upwardly along the outside of the drill pipe, out the circulation head and up the flexible hose to the vessel again. In a second method, a large-diameter pipe known as a marine conductor pipe is put together and arranged to extend from the drilling wellhead assembly near the ocean floor to the vessel on the surface of the water. In the latter method, the drill pipe rotates within the conductor pipe with drilling fluid being circulated down through the drill pipe, through the bit at the bottom thereof, up the outside of the drill pipe and thence upwardly through the annular space between the conductor pipe and the drill pipe, returning to the barge in the conventional way. The present invention is concerned with apparatus to be used in the second method described hereinabove.

One of the problems in drilling underwater wells from floating vessels is that of providing suitable means for suspending and/or supporting a large-diameter marine conductor pipe and auxiliary smaller-diameter equipment or well-control pipes in the water beneath the drilling vessel while the lower ends thereof are secured to a wellhead assembly positioned near the ocean floor. A further problem is encountered at times when drilling at olfshore locations due to the possibility of a violent storm which necessitates moving the drilling vessel away from the well being drilled or having it moved away by abnormal wind and wave action. In the cases where the vessel has to be moved or is liable to be moved, it is necessary to quickly disconnect the marine conductor and auxiliary lines from the drilling wellhead assembly near the ocean floor and withdraw them to the vessel prior to the vessel moving oif location.

Summary 0/ the invention It is therefore a primary object of the present invention to provide a marine conductor pipe assembly which can be quickly disconnected from a wellhead drilling assembly at the ocean floor while control of the well being drilled is maintained by suitable blowout equipment left on the ocean floor.

Another object of the present invention is to provide a marine conductor pipe assembly of rugged design which can be built in sections small enough to be handled easily on a drilling vessel while being provided with means for connecting the various sections together easily and quickly.

A further object of the present invention is to provide means on the sectionalized marine conductor pipe assem bly whereby smaller-diameter auxiliary pipes extending from the vessel to the drilling equipment at the ocean floor may be readily removed or replaced in case of emergency or damage without pulling the marine conductor pipe assembly back to the vessel.

These objects have been attained in the present invention by providing apparatus for carrying out operations with respect to an underwater well including a marine conductor made up of individual large-diameter pipe sections connecti-ble in an end-to-end manner. Each of the pipe sections incorporates integral track guide means which in a preferred form comprises angle irons having one edge secured to the section to extend radially outwardly therefrom and defining a slot. The slots of the various sections are in substantial alignment with one another and cooperate with T-shaped guide means secured to small-diameter pipe strings to maintain the pipe strings in a substantially parallel spaced relationship with respect to the marine conductor pipe sections. Disconnect couplings are provided to releasably secure the pipe strings and the marine conductor to an underwater wellhead assembly.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic view taken in longitudinal projection illustrating a floating drilling vessel positioned at the surface of the ocean with an underwater wellhead assembly positioned on the ocean floor;

FIGURES 2A and 2B are longitudinal views adapted to be arranged end-to-end to show enlarged detail sections of the marine conductor pipe assembly of the present invention as it is positioned on a wellhead at the ocean floor;

FIGURE 3 is an enlarged cross-section view of the marine conductor pipe assembly shown in FIGURE 2B taken across cut lines 3-3;

FIGURE 4 is a enlarged cross-sectional view of the marine conductor pipe assembly taken along cut lines 4-4 of FIGURE 3;

FIGURE 5 is an enlarged cross-sectional longitudinal view showing in enlarged detail the manner in which as illustrated, floating at the surface of a body of Water 12 and being substantially fixedly positioned over a preselected drilling location by suitable barge-positioning means or by being anchored to the ocean floor 13 by suitable anchors (not shown) connected to the anchor lines 14 and 15. Equipment of this type may be used when carrying on well drilling operations in water depths varying from about 100 to 1500 feet or more. The drilling vessel is equipped with a suitable derrick 16 as well as other auxiliary equipment needed during the drilling of a well such as a hoist system 17, rotary table 18, etc. The derrick 16 may be positioned over a drilling slot or well which extends vertically through the vessel in a conventional manner. When using the equipment of the present invention, the slot of the vessel may be centrally located or extend in from one edge. However, drilling operations may be carried out over the deck of the vessel which is cantilevered out over one end. Additionally, it is to be understood that the equipment of the present invention may be also used when drilling a well from any suitable operational base positioned above the surface of the water, such, for example, as from a drilling barge having legs extending to the ocean floor or from a platform permanently positioned on the ocean floor.

A typical underwater well head structure is illustrated in FIGURES l and 2A as comprising a base member 21 which is positioned on the ocean floor 13 and is fixedly secured to a conductor pipe or a large-diameter well casing 22 by means of a *ball-and-socket joint 23. During drilling operations a drilling wellhead assembly is removably secured to the top of a foundation pile 24 which in turn is secured to the top of the ball-and-socket joint 23. In the wellhead structure illustrated, the drilling wellhead is secured to the top of a casinghead 25 which in turn is mounted at the top of the foundation pile 24. The combined casing 22, foundation pile 24 and casinghead 25 form a continuous tubular member or pipe extending up from the ocean floor through which drilling operations are conducted.

The drilling wellhead assembly illustrated includes a detachable wellhead connector or drilling bonnet 27 of any type well known in the art. Fixedly secured above the casinghead 25 is a ram-type blowout preventer unit 28, a bag-type blowout preventer unit 29, a flexible joint 30, a remotely-operable quick-disconnect coupling and sealing apparatus 31, and a sectionalized marine conductor pipe assembly 32 (FIGURE 1) extending to the vessel 11 at the surface.

As shown in FIGURE 23, the marine conductor pipe assembly consists of a marine conductor pipe 33 having an enlarged telescoping section 34 into which the upper end section 35 of the marine conductor pipe is arranged for sliding vertical movement, thus compensating for rise and fall of the vessel with wave action or tides. Near the upper end of the upper telescoping section 35 is a discharge port 36 which communicates the internal bore of the marine conductor pipe assembly 32 with the drilling fluid circulatory system. The usual flow of drilling fluid is through the drill string bore down to the drilling bit where the earth cuttings are washed up and suspended and then circulated up the annulus between the drill string and the inner wall of the marine conductor pipe and discharged through the port 36 into a sump reservoir.

The upper end of the telescoping pipe section 35 may be secured to the drilling vessel 11 in any suitable manner, as by

cables

47 and 48. The upper end of the marine conductor pipe assembly below the upper telescoping section 35 is supported from the vessel by means of

cables

49 and 50 which extend to any suitable type of constant tension hoist means 51 and 52 which are mounted on the vessel 11.

The sections of marine conductor pipe below the telescoping section 34 are joined end-to-end by any suitable type of coupling. One such suitable type of coupling, for example, is illustrated in FIGURES 3 and 4 wherein one section 33 of marine conductor pipe is provided with the male section 41 of a stab-type fitting having conical recesses 43 formed therein for receiving the locking bolts 44 carried by the female section 42 of the coupling provided on the end of the adjacent section 33a of marine conductor pipe. It is apparent that the bolts 44 are of a form that may be turned by a diver with a wrench or by an underwater robot.

Also provided on each section of marine conductor pipe are track guide means, such track guide means being designated by reference numeral 53 with respect to pipe section 33 and by reference numeral 53a with respect to pipe section 33a. Track guide means 53 and 53a have slots 54 and 54a extending the entire length thereof to receive

legs

56 and 56a of T-shaped pipe guide means 55 and 55a respectively. The T-

guide legs

56 and 56a are secured to

sleeves

58 and 58a respectively which concentrically receive small-diameter pipe strings 39 and 40, which, in this case, for example, may be choke and kill lines.

The T-guides 55 and 55a and guide

tracks

53 and 53a cooperate to secure the choke and kill

pipe strings

39 and 40 radially to the marine conductor pipe 33 but permit them to be installed or withdrawn independently of said marine conductor pipe. Preferably

sleeves

58 and 58a are rotatively positioned on at least one of the associated pipe strings and held axially with respect thereto by means of collars, such as

collars

59 and 59a that are secured to said pipe by Welding, for example. This arrangement is illustrated with respect to pipe string 39 in FIGURES 3 and 4.

The rotary relationship between each

sleeve member

58 and 58a and its respective pipe 39 allows each T-guide 55a to be aligned with the foregoing T-guide 55 and the guide track slots 54 and 54a subsequent to the addition of each respective section of pipe which compositely form the pipe string 39 to permit free running along the entire length of the marine conductor pipe in the cooperating guide tracks. If desired, however, one or both of the pipe strings may have the T-shaped pipe guide means 55 and 55a rigidly secured thereto as by welding such as is shown with respect to pipe string 40 in FIGURES 3 and 4.

It is pointed out that the guide tracks 53 and 53a extend radially out from the marine conductor pipe 33 a suflicient distance to allow the T-guides 55 and 55a to unobstructively pass the outermost radial shoulder of end couplings 42. The bolts 44 are in the position shown by FIGURE 4 for purposes of illustrative clarity only and are in fact angularly spaced around the circumference of the couplings 42 so as to leave an unobstructed longitudinal path for the passage of the T-guides.

Guide tracks 53 and 53a may be constructed of continuous or intermittent lengths of two angle irons, each having one edge secured, as by welding, to the outer surface of the

marine conductor pipes

33 and 33a between the end couplings 41-42. The other edges of the angle irons are spaced, each oppositely facing the other, to form the slots 54 and 54a through which the

legs

56 and 56a of the T-guides 55 and 55a, respectively may extend. Alignment plates 62 and 62a may be provided proximately of the top and bottom ends of the guide tracks to hold the outer radial face of the T-guides snugly against the inner radial face of the guide tracks 53 and 53a. As may be observed from FIGURE 4, the longitudinally opposite ends of alignment plates 62 and 62a taper away from the middle shoe portion of same to funnel the T-guides into the unobstructed passage portion between the alignment plates and the guide tracks.

Each angle iron is braced along its length by gussets such as gussets 57a (FIGURE 3). In the case of intermittently spaced guide tracks, the spacings between longitudinally adjacent tracks 53 and 5311 should be relative to the longitudinalspacing between the T-guides so that a substantial portion of the length of the auxiliary lines is supported by the guide tracks at any axial position of said auxiliary lines. In general, the length of the individual T-guides should be greater than the length of the individual guide tracks 53, 530.

Although the guide tracks have been described as being connected directly to the outer surface of the marine conductor pipe, it is to be understood that they may also be secured to the outer surface of buoyancy tanks which may surround and jacket each marine conductor pipe section. Moreover, it should also be understood that the relationship between the guide tracks and the T-guide may be reversed with the T-guide mounted on the marine conductor pipe and the guide tracks secured to the

auxiliary pipes

39 and 40.

The lower ends of the

auxiliary lines

39 and 40 are provided with quick-disconnect couplings 63 and 64 (FIG- URE 2A). One form of a quick-disconnect coupling for use at the lower end of the

auxilary lines

39 and 40 is shown in FIGURE 5 as comprising a housing 78 in which auxiliary pipe 39 can be stabbed. The pipe 39 is provided with

seals

79 and 80 above and below discharge ports 81 in the side wall of the pipe and annular passage 82 is provided in the housing 78 and around the ports 81 with a discharge of fluid passing port 83 and thence downwardly to the flexible line 39a (FIGURE 2A). The lower end of the pipe 39 (FIGURE 5) is closed by a plug 84. A shoulder 86 is provided on the lower end of the housing 78 and is adapted to be engaged by spring-type latching fingers 87. The upper beveled surface 88 of each latching finger 87 is flatter than the beveled surface 89 thereof, thus allowing the latching device to be stabbed and locked in place with only a 500 pound pressure, for example, while, say, a 2000-pound pull is needed to pull it out of its latched position.

To insure proper alignment of the lower ends of

auxiliary lines

39 and 40 with the receptacles of quick-

disconnect couplings

63 and 64, respectively, guide

tubes

104 and 105 having funnel shaped upper ends are secured to the outer sleeve portion 89 of the coupling and sealing apparatus 31. The guide tubes are secured to the coupling 31 in coaxial alignment with the quick-connect couplings. The guide tubes are also in radial alignment with the

auxiliary conduits

39 and 40 when secured to their

respective guide tracks

53a and 53. Since the outside diameter of the coupling 31 may be larger than that of the marine conductor pipe female coupling sections 42, however, it may be necessary to provide the lower sections of

auxiliary lines

39 and 40 with radially extending dog-

legs

45 and 46, respectively, to accommodate the radial dimension differential between auxiliary line axis and the axis of quick-

disconnect couplings

63 and 64.

In the event that a flexible joint is employed in the drilling wellhead assembly, it is necessary that the portions of the

auxiliary conduits

39a and 40a opposite the flexible joint 30 be also flexible in order to prevent rupturing the lines. Thus, the

conduits

39a and 40a may be made of flexible hose of any suitable type. Below the flexible joint 30 (FIGURE 2A) the flexible conduit 39a becomes a rigid conduit 39b, again which is preferably provided with a valve 65 which may be remotely operated either electrically or hydraulically or may be operated by means of an underwater robot.

If the conduit 39b is merely to be used as a choke or kill line for the drilling wellhead assembly, it terminates by entering the blowout preventer 28 at flange 66 at a point below the lower set of rams of the blowout preventer. If, in addition, the conduit 39b is to be used as a cement bypass line so as to allow cement return from the well to bypass strings of casing already seated in the casinghead 25, the conduit 3% terminates at flange 67 and is provided with a valve 68 which is adapted to be operated in a manner similar to valve 65.

The coupling and sealing apparatus 31 (FIGURE 6) between the lower end of the marine conductor pipe assembly 32 and the upper end of the flexible joint 30 comprises an outer sleeve 89 secured by bolts, not shown for clarity, to a flange on the lower end of the marine conductor pipe assembly. In closely fitting concentric relationship with the internal bore 90 of the sleeve 89 is a mandrel 91 secured by bolts, not shown for clarity, to a flange on the upper end of the flexible joint 30. When in place, the mandrel 91 is locked to the sleeve 89 by a plurality of latching members 93 which are held in interference fit in a latching recess 92 around the mandrel 91 by a locking ring 94. The locking ring is reciprocated from release to holding positions by several piston actuated rods 95 secured to the locking ring around the periphery thereof. When hydraulic pressure is applied to the locking cylinder 96 via conduit 99, pressure is applied to the face of a piston to wedge the locking ring against the outer shoulder of the latching members 93. When it is desired to release the mandrel 91, fluid pressure is applied to the rod side of the locking pistons via conduit 103 to withdraw the locking ring 94 to the release position where radical clearance is allowed between

beveled edges

97 and 98 of latching member 93 and the locking ring 98, respectively. This radial clearance allows the latching member 93 to move radially out of latching recess 92, thereby freeing the mandrel 91 for axial movement relative to the sleeve 89 so that the marine conductor pipe above the flexible joint 30 can be pulled away and disconnected from the drilling wellhead assembly in an emergency.

When in the locked, drilling position, the annular space between the mandrel 91 and the sleeve 89 is sealed in a fluid-tight manner by member 101. Sealing pressure is applied to the chamber 102 extending peripherially around the sealing member 101 between same and a section of the sleeve 89. The sealing pressure is applied through a spur conduit 100 in communication with the locking pressure conduit 99.

It is to be understood that all of the various components of the wellhead drilling assembly may be remotely actuable, as by being operated by hydraulic pressure lines extending from the vessel at the surface. In the arrangement shown in FIGURES 2A and 2B, hydraulic hoses extend downwardly from the vessel in the form of a bundle of hoses 70 which terminate at the mounting flange 74 (FIGURE 6). Secured to the mounting

flanges

74 and 75 are respective coupling elements of conventional selfsealing, quick-connect hose couplings 72. Each individual hose 71 having a work function below the marine conductor pipe coupling 31 is provided with a coupling unit 72. Orienting connector 73 assures proper circumferential alignment of the male and female elements of the couplings 72 to prevent damage thereto by slight angular misalignments between the mandrel 91 and the sleeve 89.

It may therefore be seen that, by utilizing the present invention, a marine conductor pipe assembly may be quickly separated from the wellhead assembly when desirable or necessary without injury to the many hydraulic pressure conductor lines necessary to perform the functions of the wellhead assembly. Furthermore, with the present invention, the marine conductor pipe assembly may be operatively rejoined with the wellhead assembly with the greatest of expedition, most control lines being connected simultaneously with the connection of the marine conductor pipe. In addition to the foregoing advantages, the auxiliary small-diameter pipes for the choke and kill

conduits

39 and 40 may be independently withdrawn to the vessel, repaired and replaced in the event of plugging or other damage rendering them inoperative.

I claim as my invention:

1. Apparatus for drilling, completing and working over an underwater well, said apparatus comprising:

operational platform means positioned above the surface of a body of water;

a well base positioned below the surface of the water and including substantially vertical well base pipe means having a lower portion thereof fixedly anchored to the formation below said body of water and a portion extending upwardly above said formation;

marine conductor means comprising a marine conduc' tor pipe made up of individual large-diameter pipe sections connectible in an end-to-end relationship, said marine conductor means connectible at its lower end to the upper end of said well base pipe means with the upper end of said conductor pipe extending above the surface of the water in the vicinity of said operational platform means;

track guide means longitudinally secured to said marine conductor means on the outside thereof with at least a portion of said track guide means being operatively associated with each of said individual, large-diameter pipe sections;

auxiliary conduit means extending longitudinally parallel with said marine conductor means and closely adjacent thereto;

a plurality of pipe guide means secured to said auxiliary conduit means and cooperatively engageable with said track guide means, at least some of said pipe guide means being rotatably disposed on said auxiliary conduit means;

one of said guide means having slot means for longitudinally slidably receiving cooperating means secured to the other of said guide means.

2. The apparatus of claim 1 wherein said apparatus includes a drilling wellhead assembly secured to said upper portion of said well base pipe means.

3. The apparatus of claim 2 wherein said drilling wellhead assembly comprises:

blowout preventer means;

a disconnect coupling section secured above said blowout preventer means which is adapted to be detachably secured to the lower end of said marine conductor pipe; and

auxiliary conduit disconnect coupling means carried on the outside of said drilling wellhead assembly and in communication with the interior thereof, said auxiliary conduit means being connectable at the lower end thereof to said auxiliary conduit disconnect coupling means.

4. The apparatus of claim 3 wherein said auxiliary conduit means compirse individual choke and kill pipelines and wherein said choke and 'kill line disconnect coupling means comprise indivdual quick dsconnect couplngs at the bottom of said choke and kill pipelines.

5. The apparatus according to claim 1, wherein said track guide means incorporates said slot means and said pipe guide means comprises a plurality of T-shaped guides adapted to cooperate with said slot means.

References Cited UNITED STATES PATENTS 2,984,308 5/1961 Bauer et al. -7 3,189,098 6/1965 Haeber 175-7 X 3,215,454 11/1965 Hayes 166-0.5 X 3,221,817 12/1965 De Vries et al. 166-05 3,258,928 7/ 1966 Broadway et al. 1660.5 X 3,280,908 10/1966 Todd 285-48 X 3,330,340 7/ 1967 Hayes et al. 166-0.6 3,332,484 7/1967 Watkins 166--0.6 3,333,870 8/1967 Watkins 285-18 CHARLES E. OCONNELL, Primary Examiner.

I. A. CALVERT, Assistant Examiner.

U.S. Cl. X.R.