WO2005053865A1

WO2005053865A1 - Storage tank cleaning

Info

Publication number: WO2005053865A1
Application number: PCT/GB2004/005051
Authority: WO
Inventors: Richard Martin; James Leslie Dallas; William Skene; Barry Edwards Avard
Original assignee: Total Reclaim Systems Limited
Priority date: 2003-12-02
Filing date: 2004-12-01
Publication date: 2005-06-16
Also published as: GB0327879D0

Abstract

A cleaning assembly (10) for a storage tank comprises a fluid, delivery conduit (12) and a fluid outlet (20) associated with the conduit and adapted for location within a tank to be cleaned. The outlet may comprise a nozzle (76). A mounting (12) is provided for mounting the fluid outlet relative to the tank and an operator control (18) is provided for location externally of the tank for remotely manipulating the outlet.

Description

STORAGE TANK CLEANING

FIELD OF THE INVENTION The present invention relates to an assembly for use in cleaning a storage tank. In particular, but not exclusively, the present invention relates to an assembly for use in removing viscous fluids, solids and other materials from a fluid storage tank, such as those used in the oil and gas exploration and production industry for storing drilling fluid.

BACKGROUND OF THE INVENTION Drilling fluid is used in the oil and gas exploration and production industry and has a number of uses. A primary use of drilling fluid is to remove cuttings from a bore during a drilling operation, where drilling fluid is circulated down through the inside of a drill bit-supporting string and back up an annulus between the drill string and the bore wall, carrying the drill cuttings to surface. One type of drilling fluid, often referred to as drilling mud, is a water, synthetic or oil based liquid that includes a number of chemicals and other materials. These include Barite, which is added to increase the 'weight' (density) of the mud; chemicals added to increase the mud viscosity, for assisting in carrying drill cuttings to surface; and chemicals added to facilitate formation of a wall cake', which supports the drilled wellbore. The chemicals and other materials are typically added to the liquid base on site, to meet specific requirements of a particular drilling operation, and the mud is stored in dedicated tanks or pits. However, solids added to the base liquid have a tendency to fall out of suspension, collecting on the floor of the tank. This may create a thick, viscous layer of material on the tank floor, and in some cases solid deposits may form, typically in corners and the like. In addition, circulated drilling mud will contain smaller sized drill cuttings (known as * fines') removed from the wellbore and which tend to separate out from standing mud and collect on the base of tanks . The build up of material on the floors of the tanks must be periodically removed. This is normally carried out when drilling has been completed and the drilling mud backloaded to a supply ship, injected into a designated wellbore, or alternatively pumped into non-operational tanks or temporary storage tanks. Conventionally, the residue remaining in the mud tanks after the fluid has been pumped out or drained away is removed by manually pushing the viscous layer of material on the tank floor towards drains, tank outlets or the inlets of suitable suction pumps, and by digging out the collected solids. This is an unpleasant, labour intensive and time- consuming procedure. Also, for health and safety reasons, it is generally preferred to avoid the need for a person to enter or work within a storage tank.

SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a cleaning assembly for a storage tank, the assembly comprising: a fluid delivery conduit; a fluid outlet associated with the conduit and adapted for location within a tank to be cleaned; an outlet mounting for mounting the fluid outlet relative to the tank; and an operator control for location externally of the tank for remotely manipulating the outlet . According to a second aspect of the present invention, there is provided a method of cleaning a storage tank, the method comprising: mounting a fluid outlet within a tank to be cleaned; providing an operator control for the outlet externally of the tank; discharging fluid from the outlet; and operating the control to manipulate the outlet within the tank. The storage tank will typically be a tank for storing drilling fluids used in the oil and gas exploration and production industry. However, those of skill in the art will also recognise that embodiments of the invention may also be utilised in cleaning oil storage tanks, silos, and slurry pits. By providing for remote manipulation of the outlet it is possible to direct fluid passing from the outlet towards a desired location within the tank. The outlet preferably comprises a nozzle, to provide a high velocity jet of fluid. The fluid jet may be utilised to fluidise, break up, dissolve, displace or dilute solid or heavy deposits, and may be utilised to push material towards a drain or outlet, or towards a suction pump inlet. In many cases the assembly may be utilised to modify residue or deposits to a fluid form to facilitate removal.

Alternatively, the outlet may provide a fine spray or mist, depending on the material to be removed, cleaned or treated. Preferably, the operator control is operable to at least one of tilt and pan the outlet. Preferably, the operator control is mechanically coupled to the outlet, such that movement of the control translates to a corresponding movement of the outlet. The coupling preferably includes an elongate control member, which member is preferably adapted to transmit axial force and torque. However, in other embodiments the control may be coupled to the outlet by, for example, hydraulic, pneumatic or electrical means. Preferably, the outlet is provided in a jetting unit or module. The jetting unit may be adapted to be releasably mounted or coupled to the conduit, or may form part of the conduit, and the outlet may be mounted for rotation together with the conduit, or for rotation relative to the conduit, typically about a main axis of the conduit . In a preferred embodiment at least part' of the jetting unit is adapted for rotation relative to a portion of the conduit such that, for example, the conduit may be fixed relative to the tank and at least a part of the jetting unit rotated relative to the tank. A mechanical link may extend through or adjacent the conduit and the link may be rotatable relative to the conduit to transfer rotation to the unit. The jetting unit may include a body and an outlet portion adapted to be pivoted about a further axis relative to the conduit. The further axis may be a lateral axis. In a preferred embodiment the jetting unit comprises two outlet portions, one to either side of the body portion, which will avoid the creation of an unbalanced torque on the conduit. One or both of the body portion and the outlet portion may be tubular and preferably the body and outlet portions are in fluid communication with each other, such that fluid may pass from the body portion directly into the outlet portion. The outlet portion may be rotated about said further axis by any appropriate arrangement, and in a preferred arrangement axial movement of a mechanical link extending through or adjacent the conduit is translated to rotation of the outlet portion. In one embodiment the link comprises a rack engaging a pinion coupled to the outlet portion. Preferably, the pinion is mounted on a spindle on an axis of rotation of the outlet portion. Preferably, the rack is mounted to the body portion. Advantageously, the rack is mounted to the body portion so as to permit the rack to be translated relative to the body portion. Preferably, the rack is slidably mounted to the body portion. Preferably, the body portion comprises a fixed outer casing of solid tubing, which is preferably adapted for coupling to adjacent lengths of tubing. The body portion may comprise two or more relatively rotatable parts. One part of the body portion may be adapted for coupling to another part of the assembly, such as a conduit portion, and may be fixed relative to said conduit portion. A bearing may be provided between the parts of the body portion. The operator control may take any appropriate form, but preferably comprises a body, which may form part of the conduit, and a control member mounted to the body. The control member may take any appropriate form, but preferably takes the form of a lever or handle. The control member is preferably pivotable about an axis of the conduit, to pan the outlet from side-to-side. The control member may be rotatable about the conduit axis and about at least a portion of the body adapted to be fixed to or form part of the conduit. Preferably, the control member is movable relative to the operator control body to induce axial movement of a mechanical link extending through or adjacent the conduit to the outlet. Preferably, the control member is a lever which is pivotably mounted to the control body and coupled to the mechanical link. The relative distances between the pivot mounting to the control body and the mechanical link may thus be determined to provide an appropriate mechanical advantage. The operator control body may be tubular such that fluid may be directed therethrough towards the fluid outlet of the cleansing assembly. The operator control body may define a fluid inlet, whereby fluid may be directed into the body. Preferably, the fluid delivery conduit comprises a rigid tubular body. The body may accommodate a link between the operator control and the outlet. The outlet mounting may comprise an arrangement for mounting the fluid delivery conduit relative to the tank, typically for mounting the conduit such that the conduit may extend through an opening into the tank. In most applications the opening will be in a roof or upper portion of the tank, but in other applications the opening may be formed in a side wall of a tank, or even in a tank floor. The opening may be an existing opening, or may be cut in the tank. The mounting may take the form of an adjustable frame, and may be adapted to releasably engage the tank or other structure . Preferably, the mounting arrangement is configured to releasably engage the conduit. The mounting may include a lifting arrangement to facilitate deployment and retrieval of the conduit. In a preferred arrangement the conduit defines one or more profiles adapted to engage with one or more portions of the mounting, to support and prevent rotation of the conduit . The profiles may be utilised to support the conduit during a cleaning operation, or to provide temporary support for the conduit or parts of the conduit during deployment or retrieval . The outlet mounting may include a lifting arrangement for use during deployment and retrieval .

Where provided, one or more of the jetting unit body and the control body may include profiles for engaging with the lifting arrangement. Preferably, the parts of the assembly, and in particular the conduit, outlet and operator control, are formed of parts of weight and dimensions suitable for manual handling, such that the assembly may be deployed, used and retrieved with little if any mechanical assistance being required. This is of particular assistance in offshore applications, where access and the availability of lifting equipment may be restricted. The assembly may include conduit portions comprising tubular portions having ends adapted for coupling to adjacent tubular parts. One or more conduit portions may be utilised to provide a conduit of a desired length. The assembly may further comprise an anchor for locating the conduit relative to the tank floor. The anchor may be adapted to be releasably coupled to the tank floor, and may be magnetic. The anchor may define a socket/mounting for receiving an end of the conduit in a rotating fit. This may facilitate rotation of the conduit relative to the tank. Preferably, the assembly includes a plurality of outlets. In a preferred embodiment, two outlets are provided and are directed in the same direction. However, other embodiments may have outlets directed in different directions, and the assembly may include a valve for selectively opening and closing one or more of the outlets . The assembly may include a first outlet adapted to direct a jet of fluid in a direction along a length of the conduit, and at least a further outlet for directing a jet of fluid in a different direction. The first outlet may facilitate clearing of material from a floor of the tank directly below the conduit, which may assist in mounting the conduit relative to the tank. The assembly may include a pump for supplying fluid to the conduit, or may be adapted to be coupled to a pump which may be separate from the assembly. For example, charge pumps (used to feed main rig pumps) or mix/transfer pumps may be used. However, where the assembly includes a dedicated, integral pump, this may free up the charge or mix/transfer pumps for their primary uses . The assembly may be adapted to draw fluid from the tank and to direct this fluid towards the outlet. Thus fluid already present in the tank may be circulated through the assembly. Alternatively, the assembly may be adapted to draw fluid from a fluid source separate from the tank. This may allow, for example, a cleaning fluid to be jetted into the tank for cleaning purposes. The fluid may be compatible with the existing fluid or solids in the pump. For example, where it is desired to remove a relatively thick residue from a tank that has been used to store oil-based mud, the assembly may use oil as a working fluid to displace and thin the residue, which may then be directed into another tank for reuse or processing. Another aspect of the present invention relates to an agitator for location in a storage tank, the agitator comprising: an agitating member; and at least one fluid outlet associated with the agitating member and arranged such that discharge of fluid from the outlet induces movement of the agitating member . The invention also relates to a method of agitating a fluid. Preferably, the agitating member is adapted for rotation. A fluid outlet may be provided on the agitating member spaced from the axis of rotation of the agitating member. In a preferred embodiment, two fluid outlets may be provided, one towards each end of the agitating member. The agitating member may be in the form of an impeller, and preferably is a hydrofoil. The agitator may form part of an assembly incorporating some of the elements of the cleaning assembly as described above.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a cleaning assembly in accordance with a preferred embodiment of the present invention; Fig. 2 is an enlarged perspective view of a control module of the cleaning assembly of Fig. 1 ; Fig. 3 is an enlarged perspective view of an intermediate conduit extension of the cleaning assembly of Fig. 1; Fig. 4 is an enlarged perspective view of a rotating jetting module of the cleaning assembly of Fig. 1; Fig. 5 is a view showing internal detail of the rotating jetting module of Fig. 4; Fig. 6 is an enlarged perspective view of a deployment frame, lifting post and lifting bracket of the cleaning assembly of Fig. 1; Fig. 7 is a further enlarged view of the deployment frame of Fig. 6; and Fig. 8 is a perspective view of an agitating assembly in accordance with a further alternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS Reference is first made to Fig. 1 of the drawings, which illustrates a cleaning assembly 10 in accordance with a preferred embodiment of the present invention. The assembly 10 is illustrated in its operating position together with an associated deployment frame 12, lifting post 14 and lifting bracket 16. As will be described, in operation, the lifting post 14 and associated items are removed. The deployment frame 12 is adapted to be mounted above an opening in a tank to be cleaned. A control module 18 is located outside the tank, in an operator accessible position. A rotating jetting module 20 is located within the tank and is coupled to the control module 18 via, in this case, two intermediate conduit extensions 22. As will be described, the jetting module 20 may be remotely manipulated by an operator to clean the tank . Reference is now also made to Fig. 2 of the drawings, which illustrates the control module 18 in greater detail. The module 18 comprises a body 24 of solid tubing which accommodates a solid control spindle 26 which may freely rotate and move vertically up and down within a limited range within the body 24. The lower end of the body 24 is provided with a female coupling 28 which allows the module 18 to be attached to an intermediate conduit extension 22 or to a jetting module 20. The body 24 also defines external lifting/mounting lugs 30 and a fluid inlet 32, which allows fluid to be directed into the hollow body 24. A swivel joint 34 is mounted on the upper end of the body 24 and provides mounting for a control lever 36 which is coupled to the joint 34 via a linear hinge 38 and support arm 40. The control lever 36 includes a clevis portion 42 which is pinned to a sliding boss 44 on the upper end of the control spindle 26. Locking screws 46 on the boss 44 may be tightened to fix the boss 44 to the spindle 26, such that raising and lowering the control lever 36 raises and lowers the spindle 26. Reference is now also made to Fig. 3 of the drawings, which shows an intermediate conduit extension 22. The extension 22 comprises a fixed outer casing or body 48 of solid tubing and an inner solid control spindle 50. The body 48 is provided with pairs of lifting/mounting lugs 52 and male and female couplings 54, 55 for securing the body 48 to adjacent parts of the assembly. Also, the ends of the control spindle 50 are provided with non-rotating couplings 56. In the illustrated embodiment, the upper male coupling 54 engages the female coupling 28 on the lower end of the control module body 24 , while the lower female coupling 55 engages with a male coupling of a further extension 22, the further extension being coupled to the jetting module 20. Reference is now also made to Fig. 4 of the drawings, which illustrates the jetting module 20. In a similar manner to the control module 18 and the conduit extensions 22, the jetting module 20 includes a body 60 comprising a fixed outer casing 62 of solid tubing which accommodates an inner solid control spindle 64. The upper end of the body 60 includes a male coupling 66 which, in this particular embodiment, engages a female coupling 55 at the lower end of the lowermost conduit extension 22. The body 60 also defines lifting/mounting lugs 68. Mounted to the lower end of the fixed casing 62, via a rotary coupling 70, is a rotating casing 72. Two short tubular portions 74 extend laterally from the rotating casing 72 and provide mounting for respective fluid jetting nozzles 76. The nozzles 76 are hollow, such that fluid may pass directly from the casing 72 and through the nozzles 76. Reference is now also made to Fig. 5 of the drawings, which illustrates some internal detail of the jetting module 20. In particular, Fig. 5 illustrates the lower end of the control spindle 64, to which is mounted a toothed rack 78, the rack 78 being coupled to the rotating casing 72 by a sliding support and guide 80. The rack 78 engages a pinion 82 mounted on a spindle 84 which lies on the lateral axis of rotation of the fluid jetting nozzles 76. The ends of the spindle 84 are fixed to the nozzles 76, such that axial movement of the spindle 64 and rack 78 will result in rotation of the nozzles 76. Reference is now made to Fig. 6 of the drawings which shows the deployment frame 12, lifting post 14 and lifting bracket 16. The deployment frame 12 includes a housing 90 for the lower end of the sectional lifting post 14, the upper end of which includes an anchor and support point 92 for a lifting device (not shown) . The lifting device supports the lifting bracket 16, which includes a safety catch 95. The lifting post 14 further provides mounting for a safety device 96 which may be used to prevent slipping of the control module 18 during assembly and also prevents surplus chain or wire from fouling the assembly. Reference is now also made to Fig. 7 of the drawings, which shows the deployment frame 12 in greater detail. The deployment frame 12 comprises a generally square plate 98 having a central aperture 99 which is normally substantially covered by hinged retaining plates 100. The plates 100 each define a semi-circular profile 102 for gripping a section of body or casing. The profiles 102 may be moved on the plates 100 by sliding adjusters 104. Furthermore, the retaining plates 100 may be fixed in the closed position by releasable locking tabs 106. To facilitate handling, the plate 98 features lifting handles 108 and to facilitate mounting of the frame 12 in different shaped or sized apertures extendible members 110 extend from one side of the plate 98, and may be locked in a desired position by locating pins 112. An adjustable clamp 114 is provided at each corner of the deployment frame 12 for holding the deployment frame rigidly in place. In use, the assembly 10 is typically deployed above a suitably sized aperture in the roof of a confined space or tank. The deployment frame 12 is first positioned and anchored to provide support for the rest of the assembly. Each module 20, 18 is then lowered sequentially either individually or in pre-assembled combinations through the aperture 99 in the deployment frame 12 using the lifting bracket 16 and by lifting and lowering the hinged retaining plates 100. After being lowered into place, the uppermost assembled module is supported in the deployment frame 12 by the lugs 30, 52, 68 locating in corresponding slots 116 in the hinged retaining plates 100. Each subsequent module is suspended by the lifting post 14 and the lifting mechanism while it is joined to the module below, supported by the deployment frame 12. When the control module 18 is in place the sliding adjusters 104 are tightened to grip and secure the whole assembly 10 and the lifting post is removed. The assembly 10 is now firmly anchored to the aperture in the top of the confined space or tank and is ready for a pipework connection, to the fluid inlet 32, which will deliver pressurised fluid by way of a suitable pump for the purposes of mixing, jetting or washing, as described below. In operation, the control lever 36 may be moved both vertically up and down and is rotatable through 360° . As the control lever 36 is raised or lowered, the rack 78 rotates the pinion 82 and thus rotates the jetting nozzles 76. The arrangement is such that when the control lever 36 is raised or lowered then the jetting nozzles 76 are similarly raised or lowered. In this embodiment, the gearing inherent in the arrangement is such that the jetting nozzles 76 may be rotated through an angle of 180° by rotating the control lever 36 through a smaller angle, in this example 45°. By virtue of the swivel joint 34, the control lever 36 may be used to rotate the control spindle 26, which is coupled to the various other control spindles, the lowermost spindle 64 being fixed to the rotating casing 72, such that rotation of the spindle 26 results in rotation of the casing 72 and the jetting nozzle 76. As noted above, fluid under pressure is fed into the fluid inlet 32 and passes through the various modules and exits in jets through the nozzles 76. Of course the various body casings are pressure sealed with integral O- rings . Thus, an operator above the tank may direct jets of fluid at any point within the tank. Typically, the assembly 10 will be utilised to remove the residue that remains in a drilling fluid tank after the drilling fluid has been drained off . This residue typically takes the form of a very thick, viscous liquid which lies on the tank floor. The jets of fluid may be used to push the residue towards an appropriate drain opening or inlet. Furthermore, when a compatible fluid is used, the fluid may also serve to dilute the residue such that it may be reused or pumped away using conventional fluid handling apparatus. In some instances, the residue may take the form of solid material, and in this case the fluid jets may be utilised to break-up and dislodge the solid material, and then wash the solid material towards a drain or suction pump inlet. If necessary or appropriate, lights or cameras or an optical viewing device or system may be provided within the tank to allow the operator to view the jetting operation. After the tank has been cleaned, the assembly 10 may be retrieved and dismantled, using the lifting post 14. Turning now to Fig. 8, there is shown a perspective view of an agitator assembly 200 in accordance with an alternative embodiment of the present invention. In this embodiment a rotary table 202 provided with a bearing bush 204 supports a sectional, rigid conduit 206. The lower end. of the conduit 206 is mounted in an anchor 208 defining a socket 210 for receiving and supporting the lower end of the conduit 206. The assembly 200 includes an outlet unit 211 comprising agitation members 212 for agitating fluid in a tank. Each agitation member 212 includes a tube 214 which is coupled to the conduit 206 and a nozzle 215 defining an outlet 217 for directing jets of fluid' into the tank as shown by the arrows C. The conduit 206 includes either an upper swivel 216a or a lower swivel 216b. Thus the conduit 206 is either rotatable relative to an inlet tube 218 about the swivel

216a, or about the swivel 216b. In use, fluid jetted out of the outlets 217 rotates the outlet unit 211, or the outlet unit 211 and the remainder of the conduit 206, about a main axis of the conduit. This generates a vortex in the fluid which aids mixing of liquids and solids in the tank to prevent or reduce settlement of solids out of the fluid onto the tank floor. This effect is enhanced by providing hydrofoil portions 220 on the tube 214, which may be skewed or otherwise shaped to enhance the vortex and thus uplift of fluid in the tank. The agitator assembly 200 thus both circulates fluid around the tank, and additionally provides a vortex to mix fluid in the tank. Additionally shown in Fig. 8 is a pump 222 provided integrally with the assembly 200, and it will be noted that an inlet tube 224 extends downwardly and thus provides an inlet 226 for drawing fluid into the assembly 200 from the tank, or for connecting to an alternative fluid source. In a variation, the assembly 200 may include a motor either for actively driving the agitator, or to act as a governor for controlling the agitator rotational velocity. Various modifications may be made to the foregoing without departing from the sprit and scope of the present invention.

Claims

CLAIMS :

1. A cleaning assembly for a storage tank, the assembly comprising: a fluid delivery conduit; a fluid outlet associated with the conduit and adapted for location within a tank to be cleaned; an outlet mounting for mounting the fluid outlet relative to the tank; and an operator control for location externally of the tank for remotely manipulating the outlet.

2. The assembly of claim 1, wherein the outlet comprises a nozzle.

3. The assembly of claim 1 or 2 , wherein the operator control is operable to tilt the outlet.

4. The assembly of claim 1, 2 or 3, wherein the operator control is operable to pan the outlet.

5. The assembly of claim 1, 2, 3 or 4, wherein the operator control is operable to both tilt and pan the outlet.

6. The assembly of any of the preceding claims, wherein the operator control is mechanically coupled to the outlet .

7. The assembly of claim 6, wherein the operator control is coupled to the outlet via an elongate control link.

8. The assembly of claim 7, wherein the control link is adapted to transmit axial force and torque .

9. The assembly of any of the preceding claims, wherein the conduit is adapted to be fixed relative to the tank.

10. The assembly of any of the preceding claims, wherein a control link extends through the conduit and the link is rotatable relative to the conduit to transfer rotation to the unit .

11. The assembly of any of the preceding claims, wherein the outlet is provided in a jetting unit.

12. The assembly of claim 11, wherein the jetting unit is adapted to be coupled to or form part of the conduit, and at least part of the unit is mounted for rotation relative to the conduit.

13. The assembly of claim 12, wherein said part of the unit is mounted for rotation about a main axis of the conduit .

14. The assembly of any of claims 9 to 13, wherein the jetting unit includes a body and an outlet portion adapted to be pivoted about a further axis relative to the conduit .

15. The assembly of claim 14, wherein the further axis is a lateral axis.

16. The assembly of claims 14 or 15, wherein the jetting unit comprises two outlet portions, one to either side of the body portion.

17. The assembly of claim 14, 15 or 16, wherein the body portion and the outlet portion are tubular and in fluid communication, such that fluid may pass from the body portion directly into the outlet portion.

18. The assembly of any of claims 14 to 17, wherein axial movement of a mechanical control link extending through the conduit is translated to rotation on the outlet portion.

19. The assembly of claim 18, wherein the link comprises a rack engaging a pinion coupled to the outlet portion.

20. The assembly of claim 19, wherein the pinion is mounted on a spindle on an axis of rotation of the outlet portion.

21. The assembly of claim 19 or 20, wherein the rack is mounted to the body portion.

22. The assembly of any of claims 14 to 21, wherein the body portion comprises a fixed outer casing of solid tubing .

23. The assembly of claim 22, wherein the body portion is adapted for coupling to adjacent lengths of tubing.

24. The assembly of any of claims 14 to 22, wherein the body portion is formed of at least two relatively rotatable parts .

25. The assembly of claim 24, wherein one body part is adapted for coupling to another part of the assembly.

26. The assembly of claim 25, wherein said one body part is coupled to a conduit portion.

27. The assembly of claims 26, wherein said one body part is fixed relative to said conduit portion.

28. The assembly of any preceding claim, wherein the operator control comprises a body.

29. The assembly of claim 28, wherein the body forms part of the conduit.

30. The assembly of claim 28 or 29, wherein an operator control member is mounted to the body.

31. The assembly of claim 30, wherein the control member comprises a lever.

32. The assembly of claim 30 or 31, wherein the control member is pivotable about an axis of the conduit, to pan the outlet from side-to-side.

33. The assembly of claim 30, 31 or 32, wherein the operator control member is movable relative to the operator control body to induce axial movement of a mechanical link extending through the conduit to the outlet .

34. The assembly of claim 33, wherein the operator control member is a lever pivotably mounted to the control body and coupled to the mechanical link.

35. The assembly of any of claims 28 to 34, wherein the operator control body is tubular such that fluid may be directed through the body towards the outlet .

36. The assembly of claim 35, wherein the body defines a fluid inlet, whereby fluid may be directed into the body.

37. The assembly of any of the preceding claims, wherein the conduit comprises a rigid tubular body.

38. The assembly of claim 37, wherein the body accommodates a control link between the operator control and the outlet .

39. The assembly of any of the preceding claims, wherein the outlet mounting comprises an arrangement for mounting the conduit relative to the tank.

40. The assembly of claim 39, wherein the mounting is adapted to mount the conduit such that the conduit extends through an opening into the tank .

41. The assembly of any of the preceding claims, wherein the mounting comprises an adjustable frame.

42. The assembly of any of the preceding claims, wherein the mounting is adapted to releasably engage the tank or another structure .

43. The assembly of any of the preceding claims, wherein the mounting is configured to releasably engage the conduit .

44. The assembly of any of the preceding claims, wherein the mounting includes a lifting arrangement to facilitate deployment .

45. The assembly of any of the preceding claims, wherein elements of the assembly define profiles adapted to engage with portions of the mounting.

46. The assembly of any of the preceding claims, wherein primary elements of the assembly are formed of parts of weight and dimensions suitable for manual handling.

47. The assembly of any of the preceding claims, comprising conduit portions comprising tubular portions having ends adapted for coupling to adjacent tubular parts .

48. The assembly of any of the preceding claims, further comprising an anchor for locating the conduit relative to a tank floor.

49. The assembly of claim 48, wherein the anchor is adapted to be releasably coupled to the tank floor.

50. The assembly of claim 49, wherein the anchor is magnetic .

51. A method of cleaning a storage tank, the method comprising: mounting a fluid outlet within a tank to be cleaned; providing an operator control for the outlet externally of the tank; discharging fluid from the outlet; and operating the control to manipulate the outlet within the tank.

52. The method of claim 51, wherein the storage tank is a tank for storing drilling fluids used in the oil and gas exploration and production industry.

53. The method of claim 51 or 52, wherein the fluid is discharged from the outlet as a fluid jet.

54. The method of any of claims 51 to 53, wherein the fluid discharged from the outlet is utilised to modify residue in the tank to a fluid form which will flow and facilitate removal from the tank.

55. The method of any of claims 51 to 54, wherein the outlet is at least one of tilted and panned by operation of the operator control .