FLUID COLLECTING DEVICE AND METHOD

Abstract

The present invention relates to apparatus and method for collecting fluid from a drill string (4) or borehole casing, the apparatus comprising a collection casing (2) having means for sealably engaging around a drill string or borehole casing to create a chamber (6) between the interior of the collection casing and the drill string or borehole casing, and one or more fluid nozzles (7) for directing cleaning fluid into the interior of the chamber, wherein the one or more nozzles are configured to direct cleaning fluid to impact the inwardly facing interior surface of the collection casing.

Claims

1. Apparatus for collecting fluid from a drill string or from a borehole casing, the apparatus comprising a collection casing having means for sealably engaging around a drill string or borehole casing to create a chamber between the interior of the collection casing and the drill string or borehole casing, and one or more fluid nozzles for directing cleaning fluid into the interior of the chamber, wherein the one or more nozzles are configured to direct cleaning fluid to impact the inwardly facing interior surface of the collection casing.

2. Apparatus as claimed in claim 1, wherein the one or more nozzles are provided at an upper region of the collection casing and configured for directing cleaning fluid in a substantially downward direction.

3. Apparatus as claimed in claim 1, wherein the one or more nozzles are configured to direct cleaning fluid such that it contacts substantially the entire internal surface of the chamber formed between the collection casing and the drill string or borehole casing.

4. Apparatus as claimed in claim 1, further comprising a pressure relief valve for relieving pressure within the chamber.

5. Apparatus as claimed in claim 1, further comprising a drain at a lower region of the collection casing for collecting drilling mud cleaned off the interior surface of the chamber.

6. Apparatus as claimed in claim 1, further comprising an external frame to the collection casing, the frame having two or more sides.

7. Apparatus as claimed in claim 1, wherein the one or more nozzles direct air into the chamber.

8. Apparatus as claimed in claim 1, wherein the one or more nozzles create an air curtain.

9. Apparatus as claimed in any claim 1, wherein 2 to 18 nozzles are provided.

10. Apparatus as claimed in claim 9, wherein 6 to 8 nozzles are provided.

11. Apparatus as claimed in claim 1, wherein a plurality of nozzles are provided and where they are spaced equidistantly around the periphery of the collection casing.

12. Apparatus as claimed in claim 1, wherein a plurality of nozzles are provided at different axial extents along the longitudinal extent of the collection casing.

13. Apparatus as claimed in claim 12, wherein the nozzles at adjacent axial extents are circumferentially offset from one another.

14. Apparatus as claimed in claim 1, wherein the collection casing is provided as two shell components which are closable together about the exterior of the drill string or borehole casing.

15. Apparatus as claimed in claim 1, further comprising movable support means within the collection casing for supporting said nozzles, the nozzles thereby being movable within the collection casing interior to create a moving fluid curtain.

16. Apparatus as claimed in claim 15, wherein the movable support means comprises two internal casing halves.

17. Apparatus as claimed in claim 15, wherein the movable support means is slidably received within the collection casing.

18. A method for collecting fluid from a drill string or from a borehole casing, comprising: engaging a collection casing around a drill string or borehole casing thereby creating a chamber between the interior of the collection casing and the drill string or borehole casing; directing cleaning fluid into the interior of the chamber by way of one or more nozzles, the one or more nozzles being configured to direct cleaning fluid to impact the inwardly facing interior surface of the collection casing.

19. A method as claimed in claim 18, wherein the one or more nozzles are provided at an upper region of the collection casing and direct cleaning fluid in a substantially downward direction.

20. A method as claimed in claim 18, wherein the one or more nozzles direct cleaning fluid such that it contacts substantially the entire internal surface of the chamber formed between the collection casing and the drill string or borehole casing.

Description

[0029] Certain embodiments of the present invention will now be described by way of example, and with reference to the following drawings of which:

[0030] FIG. 1 shows a perspective view of a fluid collecting apparatus in an open position around a drill string pipe section;

[0031] FIG. 2 shows a part cross-sectional view of the fluid collecting apparatus of FIG. 1 in a closed or deployed configuration around the drill string pipe section;

[0032] FIG. 3 shows a plan view from above of the apparatus of FIGS. 1 and 2;

[0033] FIG. 4 shows a cross-section view of the apparatus of the present invention, showing nozzle fluid flows; and

[0034] FIG. 5 shows an exterior frame for use with the present invention.

[0035] As shown in FIGS. 1 and 2, the apparatus 1 takes the form of a collection casing comprising two half cylindrical cans 2, 3 which are hingably connected so that they can sealably engage about the exterior of drill string pipe section 4. If used with a borehole casing, the apparatus cam equally engage around a joint in the borehole casing. A suitable closing mechanism, such as an over-centre lever, ensures that the two shell or can components, 2, 3, sealably engage about the drill string pipe section to prevent mud leakage from the interior of cavity 6 defined between the collection casing components and the exterior surface of the drill string pipe section 4.

[0036] Nozzles 7 are provided to allow a fluid flow to be injected into the cavity 6. The nozzles may be integrated into the collection casing wall or mounted thereon, or may be provided on a movable structure on the inside of the collection casing. The fluid flow urges any material within the cavity 6 down towards drain 8.

[0037] In use, the apparatus is clamped to the drill string pipe section at the junction 9 of two pipe sections as shown in FIGS. 1 and 2. A relative rotation is applied to the sections either side of the junction 9 so that they become disconnected. This results in mud that has been retained within the sections escaping into the cavity 6.

[0038] However, without further assistance, a certain amount of mud would be retained within the cavity 6 and on the drill string pipes 4, and would not exit via drain 8. As such, in order to ensure mud material is not retained within the cavity or on the drill string pipes, cleaning fluid, for example air, is supplied to nozzles 7 to urge any such mud material downwardly and out through drain 8.

[0039] As shown in FIG. 4, the nozzles are arranged to direct cleaning fluid to impact the inwardly facing interior surface of the collection casing. The nozzles at the upper region of the collection casing are in this regard configured to direct cleaning fluid in a substantially downward direction. As a result, cleaning fluid is directed down the internal surfaces of the collection casing, including the inward facing walls of the collection casing and the surface of the drill string (or when used with a borehole casing, the exterior surface of the borehole casing).

[0040] The injected fluid can be in this connection be directed to set up an air curtain within the cavity that drives any mud downwardly and out of drain 8.

[0041] In a further embodiment, the nozzles may be configured such that the air curtain can travel up and down the length of the collection casing. In this connection, the nozzles may be mounted on a movable support that can travel up and down within the collection casing. The movable support may in this respect take the form of an internal casing that is slidably received within the casing. The internal casing may be formed of two or more sections coupled together to form an annular member having a diameter slightly smaller than the internal diameter of the collection casing.

[0042] The nozzles are generally provided equidistantly around the circumference of the apparatus. Whilst any suitable number of nozzles may be provided, 2 to 18 are generally sufficient. In preferred embodiments 6 or 18 such nozzles are provided.

[0043] The fluid is supplied to the nozzles for a sufficient period substantially in the region of 5 to 10 seconds to ensure that all mud is dispersed from the cavity 6.

[0044] As mentioned above, the fluid used for cleaning the interior of the cavity can be air provided at between 80 and 120 psi and more preferably between 90 and 110 psi. In this regard, air can be sourced from the same supply used to control the closing mechanism for sealably locking the shell components together around the pipe exterior.

[0045] It has been found that use of the present apparatus can save around 2 to 25 litres of mud from being lost from the chamber.

[0046] In further embodiments, the nozzles may be provided at different axial extents of the collection casing to further enhance the cleaning effect. In such a case, the nozzles at different axial extents may be circumferentially offset with corresponding nozzles provided at adjacent axial extents to ensure a uniform fluid flow is maintained.

[0047] A control means may be used to control the provision of air to the nozzles, so that air waves, pulses or sweep patterns can be created to enhance the cleansing effect.

[0048] Water may be used as an alternative to air with a requirement being that the mud is not contaminated so that it can be re-used.

[0049] FIG. 5 shows an embodiment having an external frame 10 which encloses the collection casing 2, 3 on at least three sides. The frame protects components of the apparatus on the outside of the collection casing from damage and also protects operators/rig crew from pinch points created during the operation of the mud bucket. Such components may include a control panel and ducting for the injected fluid.