GB2099881A - Location detecting tools for underwater well components - Google Patents

Abstract

A tool is disclosed for detecting and giving a remote indication as to whether an underwater well component, such as a pipe hanger (22), is correctly positioned, for example properly landed in an underwater well installation (23). A spring loaded feeler (24) is adapted to engage the component (23) and when the latter is correctly positioned the feeler operates on indicator valve unit (41). Also, a television camera enables a visual indication to be provided as to whether two reference points, a washer (27) on the feeler (24) and a line (37), are aligned with the camera, indicating correct positioning of the component. <IMAGE>

Description

SPECIFICATION Location detecting tools for underwater well components This invention relates to tools for determining by operations carried out from an operational base at the surface of a body of water whether, in an underwater well assembly equipped with guidance means, a device in the well assembly occupies a specific intended position.

Subject matter disclosed in the present application is also disclosed in our co-pending United Kingdom Patent Application No.8116679 and is also related to subject matter disclosed in our co-pending United Kingdom Patent Application No. 8116737, both having the same date as the present applications and to which reference is directed.

In completing underwater oil and gas wells of the type in which multiple strings of tubing are suspended from a single tubing hanger, it is necessary to orient the tubing hanger to a known rotational position, then land the hanger while preserving its specific rotational orientation since, if the multiple string tubing hanger does not occupy a known rotational position, it becomes impossible to mate the multiple flow passages of later-installed components, such as the production upper body, with the respective flow passages of the tubing hanger. Much work has been done in the prior art to provide for orientation of the tubing hanger or like component, as seen for example in U.K. Patent Application Serial No. 2048991.However, the uncertainties involved in remote installation of well systems, particularly in deep water, are such that it has been found desirable to check the position of the landed tubing hanger, or other components, to make certain that the position is precisely the position intended. Such a check must be accomplished remotely, by operations carried out at the surface of the body of water, and no completely satisfactory tool for this purpose has heretofore been provided.

According to the present invention there is provided a tool for determining by operations carried out from an operational base at the surface of a body of water whether, in an underwater well assembly equipped with guidance means, a device in the well assembly occupies a specific intended position, the tool comprising a support connectable to a handling string; a guide device connected to the support and constructed and arranged to coact with the guidance means to maintain the support in a specific position relative to the underwater well assembly as the support approaches the well assembly; a locator device carried by the support and constructed and arranged to coact with a part of the underwater well assembly in a specific fashion only when the support and said part of the well assembly are in one predetermined positional relationship; a feeler device mounted on the support for movement from a normal position to an indicating position, the feeler device being biased to its normal position and occupying a location on the support relative to the locator device such that the feeler device engages a part of the well assembly and is thereby positively moved to its indicating position only when the device in the wellhead occupies its specific intended position and the locator device coacts with said part of the well assembly; a hydraulic or pneumatic system responsive to movement of the feeler device from its normal position toward its indicating position for providing at the operational base an observable indication of movement of the feeler device from its normal position toward its indicating position; and a second apparatus carried by the support for giving a second observable indication of the position of the feeler device.

Thus, the present invention provides a tool which can be manipulated with a handling string to determine with accuracy whether a component, such as a multiple string tubing hanger which has been orientated and then landed in an underwater well assembly, in fact occupies the intended position. Also, tools according to the present invention can provide two separate remotely observable indications of whether the component occupies the desired position, and one of said indications can be, a very marked change in hydraulic or pneumatic pressure.

A specific embodiment of the invention will now be described, by way of example, reference being made to the accompanying drawings, in which: Figures 1 and 2 are top plan and side elevational views, respectively, of the tools; Figure 3 is a view partly in vertical cross section and partly in side elevation taken generally on line 3-3, Figure 1, and showing the tool landed on an underwater well assembly and engaged with a multiple string tubing hanger forming part of that assembly; and Figure 4 is a vertical cross sectional view of a valve unit forming part of the tool of Figures 13.

The embodiment of the invention illustrated comprises a support 1 comprising an upper member 2, a lower member 3 and two guide arms 4 and 4a. Upper member 2 comprises an upstanding cylindrical hub 5 and, at the bottom of the hub, a flat transverse flange 6 secured rigidly to the hub. The upper end of the hub has a threaded socket 7, to be connected to a handling string (not shown), the socket opening downwardly into a blind bore 8 which communicates on the one hand with a radial outlet bore 9 and, on the other hand, with the interior of the handling string pipe when the hub is connected to the handling string. Lower member 3 is in the form of a flat plate of circular plan shape.

Guide arms 4 and 4a form part of a guide frame indicated generally at 10 and comprising four side members 11 arranged to define a square, a guide tube 12 being secured at each corner of the square and the guide arms 4, 4a extending along the respective diagonals of the square. Arm 4 extends continuously from corner to corner of the frame, while arm 4a is in two halves, one extending from one corner of the square to the center of arm 4, the other extending from the opposite corner to the center of arm 4.

All joints between arms 4, 4a, side members 11 and guide tubes 12 are welded to provide the rigid frame. Arms 4, 4a are of I-beam configuration. Flange 6 of upper member 2 is made up of four triangular pieces welded to the upper flanges of arms 4, 4a at the center of the frame, and lower member 3 is welded to the lower flanges of arms 4, 4a at the center of the frame. Thus, the guide arms effectively extend through the space between flange 6 and member 2.

A locator member 15, comprising a flat circular plate 1 6 of the same size as lower member 3 and two locator splines 17 and 1 7a depending from and secured rigidly to plate 16, is employed in conjunction with a locator sleeve or skirt 18 having at its upper end a transverse annular outwardly and inwardly projecting flange 19, the inner diameter of flange 19 being such that the flange snugly embraces splines 1 7, 1 7a. Bolts, as at 20, extend through aligned holes in flange 19, plate 16 and member 3, as shown, to secure those members rigidly together with locator member 15 centered on the central axis of hub 5.

Splines 1 7, 1 7a are of arcuate transverse cross section and are dimensioned to extend downwardly through the respective ones of two gaps of a flange 21 at the upper end of the body of a multiple string tubing hanger 22 supported in the bore of a wellhead lower body 23, the tubing hanger being described in detail in our aforementioned Application No. 8116737. As fully explained in that application, the two flange gaps are opposed across the hanger body and are of different arcuate width. Accordingly, spline 17 is made with a width such as to be snugly accommodated by one of the gaps, and flange 1 7a has a width such as to be snugly accommodated by the other gap.Hence, splines 17, 1 7a cannot be inserted through the gapped flange 21 of hanger 22 except when locator member 1 5 is so aligned and oriented relative to the tubing hanger that each spline 1 7, 1.7a is centered on its respective gap. Sleeve 18 of member 1 5 has a right cylindrical inner surface dimensioned to slidably embrace the upper end portion of wellhead lower body 23.

In locations spaced outwardly from hub 5 and adjacent to the web of one of the guide arms, four sets of vertically aligned openings are provided in flange 19, plate 16, member 3 and flange 6, as seen in Fig. 3. Each such set of openings accommodates a feeler rod, all four feeler rods being identical and one being shown in detail at 24, Fig. 3. At its lower end, the rod has a flat head 25 disposed for flush engagement with the upper end face of wellhead body member 23. Save for its upper tip, which has a threaded portion of smaller diameter, rod 24 is of constant diameter throughout its length and is slidably engaged by the walls of the opening in flange 6 and by an opening in the top wall of a cup-shaped spring retainer 26 carried by member 3, so the rod is retained in an upright position but free to move upwardly or downwardly.The upper end of rod 24 carries a washer 27 secured between a nut 28 and the shoulder at the lower end of the smaller diameter threaded tip portion. A compression spring 29 is housed in retainer 26 and engaged between the top wall of the retainer and head 25, so as to bias rod 24 downwardly. The length of the rod between head 25 and washer 27 is predetermined and is significantly greater than the space between the lower end of retainer 26 and the upper surface of flange 6. As will be clear by comparing Figs. 1 and 3, all of the feeler rods 24 are aligned above the annular space between the inner surface of skirt 1 8 and a cylindrical surface containing the arcuate outer faces of splines 17, 17a.

Hub 5 and respective guide arms 4, 4a are interconnected by four triangular brace plates 30 each centered on one of guide arms 4, 4a. A shroud is provided for the rod 24 shown in detail in Fig. 3 and comprises a flat background plate 31 and two flat side plates 32, 33 rigidly secured to flange 6 and extending upwardly therefrom.

Background plate 31 has its ends welded to two of the brace plates 30 while side plates 32, 33 project outwardly from the background plate and at right angles thereto to define a window through which the background plate can be viewed. Background plates 34-36 are provided, similarly to plate 31, in each of the remaining spaces between adjacent pairs of brace plates 30, as will be clear from Fig. 1.The outwardly exposed face of each background plate 31 and 34-36 is provided with a visible reference line, as at 37, Fig. 3, all of the reference lines lying in a common plane parallel to flange 6 and spaced thereabove by'a distance equal to the space between indicator washer 27 and the upper face of flange 6 when the tool is seated on the wellhead assembly with rod heads 25 engaging the upper end of body 23. Thus, when tubing hanger 22 is properly landed and oriented, and when rods 24 are in their raised indicating positions, a television camera 38 will observe washer 27 aligned with reference line 37 on plate 31, the principal axis of the lens being directed to line 37 through the position occupied by washer 27 when the feeler rod is in its indicating position.

Secured to the upper edges of shroud walls 31-33 is a mounting bar 40 having a threaded through bore aligned coaxially with feeler rod 24.

An indicator valve unit, indicated generally at 41 in Fig. 3 and shown in detail in Fig. 4, is secured in the through bore of mounting bar 40, as by external threads 42 on lower member 43 of an upright valve body 44. Body 44 is completed by an upper body member 59 and defines a cylindrical internal chamber 45, a cylinder 46 of larger diameter than chamber 45 and located thereabove, and a guide bore 47 located below chamber 45 and of smaller diameter. Chamber 45, cylinder 46 and bore 47 are coaxial. A valve seat member 48 has its right cylindrical outer surface 49 slidably embraced by the wall of bore 47. Member 48 is tubular for most of its length, so as to define an outlet passage 50 terminating in an upwardly and inwardly tapering transverse annular valve seat 51.The upper end of member 48 is outwardly enlarged to provide an outer flange 52 capable of downward engagement with a shoulder 53 provided by body member 43. Also at its upper end, member 48 has a partition 54 with through passages 55 for fluid flow and a central through bore 56. A compression spring 57 is engaged between the upper end of member 48 and a downwardly facing transverse annular shoulder 58 in upper body member 59.

A movable valve member 60 has an elongated spindle 61 and a head portion 62 presenting an upwardly directed frustoconical face 63 dimensioned to mate with valve seat 51. Spindle 61 extends upwardly through bore 56, being slidable with respect thereto, and completely through chamber 45 to terminate in a threaded upper tip engaged in a threaded blind bore in piston 64. Piston 64 has a diameter such as to be slidably embraced by the wall of cylinder 46.

Cylinder 46 opens upwardly and is closed by end wall member 66, as shown, a compression spring 65 being engaged between member 66 and an upwardly directed shoulder 67 on the piston. A radial inlet bore 68 extends through the side wall of chamber 45 and is threaded to accept a connector at one end of an external conduit 69, Fig. 1, the other end of conduit 69 being connected to bore 9 of hub 5, placing internal chamber 45 of the valve unit in communication with bore 8 of hub 5 and thus, via the bore of the handling string, with a source of fluid under pressure on the operational base at the surface of the body of water. An outlet or vent 70 is provided for cylinder 46, as shown.

Body members 43, 59 are generally tubular and secured rigidly together, as by a threaded joint between a dependent portion 59a of member 59 and the upper end portion of member 43, as shown. A fluid-tight seal is provided, as by an O-ring, between portion 59a and member 43.

Sliding fluid-tight seals are provided between valve seat member 48 and surface 47 of member 43, and between piston 64 and the surrounding cylinder wall, as shown. The guide bore 47 has a diameter significantly smaller than that of the wall of cylinder 46 so that, when the valve is closed, with line pressure still applied via inlet 68 to chamber 45, the pressure in chamber 45 acts against a larger effective area of the piston and a smaller effective area of the valve seat member and the combination of the piston, movable valve member and valve seat member is therefore moved upwardly, as a result of the difference in effective areas, until the valve seat member engages the lower end of body portion 59a.

Valve member 60 is normaliy in its lower, open position as seen in Fig. 4 so that pressure fluid supplied to chamber 45 at a constant pressure escapes via passages 55 and outlet 50. The greater effective area of piston 64 is not adequate, in view of the strength of springs 57 and 65, to provide a fluid pressure-generated force adequate to move valve member 60 upwardly. Hence, the valve remains open and fluid pressure observed by a gauge (not shown) at the source on the operational base remains steady. When rod 24 is forced upwardly to its indicating position, as a result of engagement with body 23, valve member 60 is moved upwardly to engage surface 63 with seat 51 and force valve seat member 48 slightly upwardly in guide bore 47.With the valve thus closed, and pressure fluid still supplied to chamber 45, the greater effective area of piston 64, as compared to that of a valve seat member 48, provides net force acting on the piston in excess of the spring force, so that the piston, movable valve member and valve seat member move upwardly until the valve seat member engages body portion 59a as a stop. Since fluid can no longer escape and the movable elements are stopped, an abrupt increase in pressure is observed at the operational base, signalling that the tubing hanger is properly landed in its oriented position.

It will be understood that seat 51 and surface 63 are machined to coact in metal-to-metal seal fashion, so that the mechanical action resulting from engagement of valve head 62 with feeler rod 24 is adequate for closing the valve. The increased pressure between surface 63 and seat 51 which results from continued upward movement of the piston, movable valve member and valve seat member against the biasing force of the springs adds to positiveness of closing of the valve but has the greater advantage that, since valve head 62 retreats upwardly from feeler rod 24 after the valve has been closed, there is no need for the high degree of dimensional accuracy which would be required if, once the valve closed, head 62 rigidly opposed the feeler rod.

From Fig. 4, it will be seen that, when the valve is closed, head 62 of the movable valve member is located wholly outside of the valve body. Once the valve has been actuated to close, as a result of engagement of head 62 with the upper end of feeler rod 24, the action of the valve causes head 62 of movable valve member 60 to move upwardly, away from the end of rod 24, so that indicator washer 27 is more clearly distinguishable against background plate 31.

Claims (12)

Claims

1. A tool for determining by operations carried out from an operational base at the surface of a body of water whether, in an underwater well assembly equipped with guidance means, a device in the well assembly occupies a specific intended position, the tool comprising a support connectable to a handling string; a guide device connected to the support and constructed and arranged to coact with the guidance means to maintain the support in a specific position relative to the underwater well assembly as the support approaches the well assembly; a locator device carried by the support and constructed and arranged to coact with a part of the underwater well assembly in a specific fashion only when the support and said part of the well assembly are in one predetermined positional relationship; a feeler device mounted on the support for movement from a normal position to an indicating position, the feeler device being biased to its normal position and occupying a location on the support relative to the locator device such that the feeler device engages a part of the well assembly and is thereby positively moved to its indicating position only when the device in the wellhead occupies its specific intended position and the locator device coacts with said part of the well assembly; a hydraulic or pneumatic system responsive to movement of the feeler device from its normal position toward its indicating position for providing at the operational base an observable indication of movement of the feeler device from its normal position toward its indicating position; and a second apparatus carried by the support for giving a second observable indication of the position of the feeler device.

2. A tool as claimed in claim 1, wherein the hydraulic or pneumatic system comprises an indicator valve unit mounted on the support and comprising a body defining an internal chamber and having an inlet port connectable to means for supplying pressure fluid to the chamber from the operational base, and an outflow port via which pressure fluid can escape from the chamber; a valve seat, and a movable valve member mounted to coact with the valve seat and biased to a first position relative to the valve seat, the valve seat and movable valve member being disposed to control fluid flow via the oufflow port; the indicator valve occupying a position on the support such that the movable valve member is engaged by the feeler device and moved to a second position relative to the valve seat when the feeler device moves to its indicating position; movement of the movable valve member to its second position causing a pressure change in the internal chamber, which change can be observed remotely as a first indication that the device in the well assembly occupies its specific intended position.

3. A tool as claimed in claim 1 or 2, wherein the locator device comprises at least one downwardly directed spline dimensioned to be inserted downwardly through a gap presented by the device in the well assembly.

4. A tool as claimed in claim 3, wherein the locator device further comprises a second downwardly directed spline dimensioned to be inserted downwardly through a second gap presented by the device in the well assembly, the two splines having different dimensions such that each spline can be inserted only through a corresponding one of the gaps.

5. A tool as claimed in any one of claims 2 to 4, wherein the support includes an upwardly extending member; the feeler device comprises an upright feeler rod mounted for vertical movement beside the upwardly extending member of the support, the feeler rod being movable from its normal position upwardly firstly to engage the movable valve member, then to actuate the valve member upwardly, to arrive at said indicating position, the relative positions of the feeler rod and the upwardly extending member on the support being such that when the feeler rod occupies said indicating position the upper end of the rod can be viewed against a lateral surface of the upwardly extending member as a background; and said second apparatus comprises an observable reference mark on the lateral surface of the upwardly extending member of the support, and a television camera carried by the support in a position such that the principal axis of the lens of the camera extends through both the upper end of the feeler rod and the reference mark only when the feeler rod occupies its indicating position.

6. A tool as claimed in claim 5, wherein the support comprises a centrally located upwardly projecting hub for attachment to a handling string and having a laterally projecting transverse flange spaced below the upper end of the hub, a plurality of guide arms, the annular flange of the hub being secured to the guide arms, and a lower member secured to the guide arms below the flange of the hub, the locator device being rigidly carried by the lower member and depending therefrom, the flange and said lower member having vertically aligned apertures and the feeler rod extending through the apertures.

7. A tool as claimed in claim 6, wherein said lower member of the support is flat and the support further comprises a tubular skirt secured to and depending from the lower member to embrace a part in the well assembly; the locator device comprising at least one spline depending from the lower member and spaced inwardly from the skirt, the vertical axis of the feeler rod extending through the space between the inner surface of the skirt and the outer face of the spline.

8. A tool as claimed in claim 7, wherein the guide arms constitute portions of a rectangular frame comprising four side members, there being two guide arms each extending along a different diagonal of the rectangle of the frame and secured at its outer end to the respective side member, the guide arms extending through the space between the flange of the hub and the flat lower member.

9. A tool as claimed in any one of claims 2 to 4, wherein the support comprises an upwardly projecting hub to be connected to a handling string, and a generally flat upper surface extending transversely of the hub below the upper end thereof; the feeler device comprises an upright feeler rod extending through an aperture in said flat upper surface, the upper end of the feeler rod being spaced above said flat surface when the feeler rod is in said indicating position; the tool further comprising a shroud comprising an upright wall secured to the support and projecting upwardly therefrom partially to surround the feeler rod when the rod is in said indicating position, said wall defining a window opening away from the hub and through which the feeler rod is outwardly exposed, a portion of the wall being disposed between the feeler rod and the hub; the indicator valve unit being mounted on the shroud with the movable valve member being centered above the feeler rod.

10. A tool as claimed in claim 9, wherein the second apparatus comprises an observable reference mark on said portion of the wall which is exposed through the window, and a television camera carried by the support in a position such that the principal axis of the lens of the camera extends through both the upper end portion of the feeler rod and reference mark only when the feeler rod occupies its indicating position.

11. A tool as claimed in claim 2, wherein the feeler device comprises a feeler rod; the body of the indicator valve unit has a valve seat guide bore located at one end and a cylinder located at the other end, the internal chamber, guide bore and cylinder being coaxial and the internal chamber being located between the guide bore and the cylinder; the valve seat being an outer surface of a valve seat member slidably disposed in the guide bore; the movable valve member comprises an elongate stem, a valve head fixed to one end of the stem, and a piston fixed to the other end of the stem, the piston being operatively disposed in the cylinder, the stem projecting through the internal chamber and the valve seat member, the valve head being located beyond the valve seat member, having a valve surface directed toward the seat member to cooperate with the valve seat and being disposed for endwise engagement by the feeler rod; and the indicator valve unit further comprises stop means coacting with the piston and the valve seat member to limit outward movement thereof to predetermined positions in which the valve head is spaced outwardly from the valve seat, and spring means biasing the piston and valve seat member to cause the stop means so to coact, and means responsive to fluid pressure in the internal chamber, when the valve is closed, operative to cause the movable valve member and the valve seat member to retreat from the feeler rod after engagement of the valve head with the feeler rod has closed the valve.

12. A tool substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.