WO1989012159A1

WO1989012159A1 - Fluid handling apparatus

Info

Publication number: WO1989012159A1
Application number: PCT/GB1989/000615
Authority: WO
Inventors: Philip Smith; Peter Hall
Original assignee: Quintess U.K. Ltd
Priority date: 1988-06-03
Filing date: 1989-06-02
Publication date: 1989-12-14
Also published as: AU3695689A

Abstract

A sampling tube (2) and shipping vessel (52) for use in obtaining and shipping geological fluid samples are interconnectable so that fluid may be transferred from a space (6) within the sampling device directly to an expansible fluid receiving chamber (124) in the shipping vessel. Prior to effecting the transfer, the chamber volume (124, 122) is reduced to zero to exclude contaminants such as air, the tube and shipping vessel are interconnected and the sample containing space within the tube placed in direct communication with the expansible chamber for effecting the transfer.

Description

FLUID HANDLING APPARATUS

This invention relates to fluid handling apparatus and is particularly applicable to the handling of fluid samples from well bores, for example in the oil ^"industry.

The sampling of fluid from well bores at the level of the producing formation is an accepted practice and various designs of bore hole sampling tools exist for this purpose. The sampling tool is lowered into the well bore to the level at which the sample is required, a sample is then permitted to enter the sampling tool, the tool withdrawn and then the sample has to be transferred from the tool to a shipping bottle. One known method of transferring the sample from the bore hole sampling tool to the shipping bottle involves the use of a transferring apparatus with steel tubes connecting the sampling tool to the shipping bottle and a transferring medium, typically mercury, which interfaces with the sample to effect the transfer of the sample from the sampling tool to the shipping bottle. An alternative method of effecting the transfer of the sample from the sampling tool to the shipping bottle involves evacuating the steel tubes which interconnect the sampling tool and the shipping bottle.

The use of mercury is unacceptable in certain areas because of its corrosive nature, the personal health

^"risk involved in handling mercury and the environmental risk of pollution and long term contamination resulting from mercury spillages.

The transfer by means of drawing a vacuum in the steel tubing which interconnects the shipping bottle and the sampling tool during the transfer operation can also be hazardous as, during the transfer process, high pressure may be released into tubes subjected to a vacuum. This may cause or reveal leaks in the system which can result in loss or contamination of the fluid sample.

According to one aspect of the present invention, a bore hole sampling tool and sample shipping bottle are designed to enable the transfer of the sample from the sampling tool to the shipping bottle to be effected at the pressure and temperature at which the sample was_. taken without the use of interconnecting steel tubes or any transferring medium. This is achieved by directly coupling the sampling tool to the shipping bottle rendering the use of interconnecting steel tubes or a transferring medium which interfaces with the sample unnecessary.

According to another aspect of the invention, a seal for use in transferring fluid at high pressure and/or temperature comprises two mating sufaces normally forming a hermetic seal by being in contact under substantial compressive force said force being maintained by locking means so that, in use the locking means may be relieved of the opposing force to said compressive force by hydraulic ram means so that the locking means may be withdrawn and the said two mating surfaces may be separated by operating said hydraulic means to reduce the compressive force in a controlled manner and further so that, in use, the said two mating surfaces may be brought together under substantial compressive force by operating said hydraulic means until a hermetic seal has been re-established between the said mating surfaces and the locking means has been repositioned to absorb and substantially maintain . -.the compressive force introduced by the hydraulic means on said mating surfaces.

According to a further aspect of the invention the separation of the two mating surfaces may be controlled in use by movement of a piston forming part of the sampling tool.

According to a further aspect of the invention a sample fluid transfer system ^• comprises buffer fluid maintained at a pressure sufficient to maintain the sample fluid in its monophasic condition during the transfer process. Said buffer fluid is not in direct contact with the sample fluid.

According to another aspect of the invention a sample fluid transfer system comprises two buffer fluid volumes, neither of which contains mercury.

The combination of sampling tool and shipping bottle is arranged to facilitate the movement of fluid from the sampling tool to the shipping bottle while maintaining the fluid at high pressure and/or elevated temperature and avoiding any contamination of the sample fluid with any other fluid or substance.

The invention is described further by way of example with reference to the accompanying drawings, in which: Fig. 1 is a sectional view through a sampling tool according to a preferred embodiment of the invention, showing the tool in a condition ready to receive a sample;

Fig. 2 is a sectional view through a shipping vessel according to the preferred embodiment of the invention with the sampling tool of Fig. 1 connected thereto for the purpose of transferring the sample from the tool to the shipping vessel;

Fig. 3 is a sectional view similar to Fig. 2 but showing the parts in a difference position;

Fig. 4 is a partial sectional view similar to Figs. 2 and 3, but showing the parts in a condition in which transfer is taking place;

Fig. 5 is a partial sectional view similar to Fig. 4 but showing transfer completed; and

Fig. 6 is a partial sectional view through an alternative embodiment of the invention. With reference to Fig. 1, a sampling tool (2) for obtaining fluid samples from well bores comprises a sampling tube (4) having a hollow interior (6), a collett (8) threaded into an upper portion (9) of the hollow interior (6) of the tube (4) and moveable axially thereof by rotation, a cap (10^") screwed by threads (11) onto the top end of the tube (4) and forming a fluid tight seal therewith, and a nose (12) screwed onto threads (14) at the lower end of the tube (4) and also forming a fluid tight seal therewith. Appropriate fluid seals may be provided between the tube (4) and the cap (10) and nose (12) but these are not shown in the drawings, for simplicity.

The hollow interior (6) of the tube (4) is of circular cross-section and therefore forms a cylinder. The nose (12) includes a first hollow interior portion (16) which is of circular- cross-section the same as that of the interior (6), and a second hollow interior portion (18) also of circular cross-section but of smaller diameter than that of the portion (16) . The hollow interior (6) and the portion (16) are in alignment so that one forms a continuation of the other. An annular piston (20) is slideably mounted on a rod (22) for axial movement along the cylinder formed by spaces (6) and (16). Movement of the annular piston (20) in the upwards direction is limited by a stop (24) secured to the rod (22). Downward movement of the piston (20) ^• along the rod (22) is limited by a further piston (26) fixed to the bottom end of the rod (22). The piston (26) includes an enlarged portion (28) which is a sliding fit within the cylinder formed by spaces (6) and (16) and a reduced diameter portion (30) which fits within the space (18) of nose (12). Fluid seals (32) and (34) are provided respectively on the outer and inner surfaces of the annular piston (20) and a fluid seal (36) is provided on the outer surface of the enlarged portion (28) of piston (26).

The collett (8) is provided with a downwardly directed recess (38) adapted to receive the upper end of the rod (22) which is provided with an annular grove (40) for locking engagement with balls (42) mounted in the collett (8) adjacent recess (38). The balls (42) are urged inwardly by spring means (not shown) so that when the upper end of the rod (22) is inserted into the recess (38), locking takes place automatically. A mechanism (not shown) is provided for releasing this lock to permit the rod (22) to be disconnected from the collett (8). Such mechanisms, which may for example comprise an axially movable sleeve (not

SUBSTITUTESHEET shown) for relieving the action of the aforementioned spring means on the balls are conventional and further description will therefore not be given.

A pipe (44) connected to a source of hydraulic fluid (not shown) is connected to the cap (10). Communication between the pipe (44) and the space (6) for the supply of hydraulic pressure thereto is via passages (46) and (48) in the cap (10) and collett (8) respectively. The nose (12) is provided with a radially extending passage (50) connecting into the space (16) at a position adjacent the lower part of the annular piston (20).

The tool (2) is constructed to withstand high internal and high external pressures.

In order to obtain a sample with the tool (2), the parts are arranged in the postion shown in Fig. 1 with hydraulic pressure applied to the space (6) and the tool is lowered into the well bore to the level required. The hydraulic pressure in space (6) is then reduced and the pressure of the surrounding fluid is communicated to the interior of the tool through passage (50) at a point between the pistons (20) and (28) thereby forcing the piston (20) to slide up the rod (22) until it hits the abutment (24) with sufficient force to move the rod (22) upwardly, bringing the piston (26) with it, and causing the upper end of rod (22) to enter the space (38) in collett (8) and become locked therein. In this way, the space within tube (4) between pistons (20) and (26) becomes filled with the required fluid sample which, as is well known, is at high pressure. The movement of the rod (22) upwardly into the recess (38) is sufficient to move the enlarged portion (38) of the piston (26) out of the nose (12) and into the lower end of tube (4) .

After the tool has been removed from the well bore, the cap (12) is removed from the lower end of tube (4) in preparation for attachment of the tube (4) to a shipping bottle (52) shown in Fig. 2. Since, as previously described, the enlarged portion (28) of piston (26) has been moved into the lower end of the bore (6) in the tube (4), removal of the cap (12) is achieved without loss or contamination of the sample within the tube (4) .

The shipping bottle (52) is constructed to withstand high internal pressures and comprises a body (54) having a threaded bore (56) in its upper part for threadedly receiving the lower end of tube (4) in a fluid tight manner (appropriate fluid seals being provided, but not shown). The bottle (52) includes a cylindrical element (58) which, together with the body (54), defines an annular space (60) within which an annular piston (62) is located for vertical sliding movement. Inner and outer seals (64,66) are provided on the piston (62) to prevent movement of fluid past the piston.

The element (58) is mounted slideably in a bore (70) in the lower part of the body (54) and held in postion by a nut (72) having external threads (73) threaded into the lower part of body (54) . A downwardly directed annular rib (74) formed in the upper part of the body (54) mates with an annular grove (76) in the upper end of element (5^'8) to form a hermetic seal, the rib being of generally triangular section and the groove being correspondingly shaped.

A hydraulic jack (80), which is only partially shown in Fig. 2 but fully shown in Fig.3, comprises a main body (82) attached to a flange (84) of a boss (86) which is treaded into an opening (88) in the bottom of body (54) of bottle (52). A piston (90) is mounted in the body (82) and defines with the body (82) a hydraulic chamber (92) which may be connected to a source of hydraulic pressure (not shown) by a pipe (94). When the chamber (92) is pressurised, a stem (96) of the piston (90) may push the element (58) upwardly with great force, the upper end of the stem (96) passing through the centre of nut (72) for engagement with the bottom of the element (58). This force is sufficient to slightly distort the element (58) and possibly the rib (74) thereby ensuring a high degree of sealing engagement between the rib (74) and grove (76). Thus, when the chamber (92) is pressurised, the nut (72) may be easily rotated to bring it up against the bottom of the element (58), for which purpose a hand wheel (98) is rotatably mounted on the stem (96) and urged upwardly by a plate spring diagramatically indicated at (100) to maintain a lug (102) on the upper end of the hand wheel (98) in engagement with a corresponding recess (104) in the nut (72). Access to the periphery of the hand wheel (98) is via an opening (106) in the body (82). Thus, to bring the nut (72) to a postion in which it maintains the element (58) in a distorted and compressed condition to maintain the hermetic seal, the chamber (92) is pressurised and the hand wheel (98) rotated in an appropriate direction. After the nut has been screwed up tightly, the chamber (92) may be depressurised and the jack (80) removed from the vessel (54), the nut (72) maintaining the hermetic seal. Opening of the hermetic seal between rib (74) and grove (76) may be achieved by attaching the jack (80) to the body (52), pressurising the chamber (92) to relieve the pressure on the nut and then rotating the hand wheel (98) in the opposite direction to withdraw the nut sufficiently far that, upon release of the pressure in chamber (92) the element (58) may move downwardly to open the seal.

The body (54) includes a passage (110) for connecting the space (60) below piston (62) to a source of hydraulic pressure (not shown) via a pipe (112).

In order to transfer the sample from the tube (4) to the bottle (52), the lower end of the tube (4) is threaded into the top of the bottle (52) as shown in Fig. 2 and the element (58) is maintained under compression by the nut (72) . A cylindrical recess (114) in the upper part of the element (58) and a cylindrical opening (116) in the upper part of body (54) form a continuation of the cylindrical space (6) within the tube (4) and are of the same cross-section as that space (6). A reduced diameter recess (118) within the element (58) is provided for receiving the reduced diameter portion (30) of piston (26).

After attachment of the tube (4) to the body (54) as shown in Fig. 2, and with the cap (10) removed, the collett (8) is rotated by a suitable tool (not shown) inserted into the top of the tube (4) to lower the collett (8), rod (22) and pistons (20) and (26) until the enlarged portion (28) of the piston (26) is slightly below the hermetic seal (74, 76) as shown in Fig. 3. Thereafter, and whilst maintaining hydraulic pressure within the space (60) below annular piston (62), the nut (72) is withdrawn with the assistance of the jack (80) and hand wheel (98) so that a space (122) may open between the rib (74) and groove (76) as shown in Fig. 4. Then, again as shown in Fig. 4, hydraulic fluid is introduced to the tube (4) above the piston (20) with the assistance of cap (10) and this fluid is used to push the piston (20) downwardly, whilst the pressure in the space (60) below the piston (62) is controllably released, whereby to transfer the sample directly from the space between pistons (20) and (26), through the space (122) and into space (124) within body (54) and above piston (62) as again shown in Fig. 4. This is continued until the position shown in Fig. 5 is reached, where the piston (62) has reached its lowermost postion and the space (124) above the piston (62) is filled with sample. With the aid of the jack (80) and hand wheel (98), the element (58) is thereafter raised and compressed to recreate and maintain the hermetic seal between rib (74) and recess (76) . In this way, the sample may be transferred to the bottle (52) without changing its pressure. The tube (4), jack (80) and pipe (112) may then be disconnected from the shipping bottle (52) which can then be shipped to a laboratory for testing of the sample. If desired the bottle may be maintained at a particular temperature both during transfer- of the sample and shipping.

Thus, the above described embodiment enables the sample contained in tube (4) to be transferred to the shipping bottle (52) under pressure, without contact with air or any other contaminant and without the need for a substance such as mercury for achieving this transfer without contamination. This is achieved, in the illustrated embodiment, by the provision within the bottle (52) of a sample receiving chamber, consisting of the spaces (122) and (124) whose volume can be reduced to zero thereby excluding air or other contaminant together with the ability to connect the tube (4) to the bottle (52) in a manner which places the sample within the tube (4) in direct communication with these spaces without any intervening voids or transfer fluid such as mercury.

When the bottle (52) has been transported to a laboratory, the fluid may be removed therefrom with an appropriate connecting device which connects to the bottle (52) in a manner similar to the tube (4) and thus the sample may be removed under controlled conditions.

In the modified embodiment of Fig. 6, the upper end (130) of the element (58) has a flat annular surface which engages a resilient seal (132) provided in a groove (134) in the upper portion of the body (54), instead of the sealing arrangement (74,76) shown in Figs. 1 to 5. Otherwise, the embodiment of Fig. 6 may be the same as that of Figs. 1 to 5.

Although the invention is particularly useful in handling fluid samples from well bores, in which art particular problems arise, the invention could be applied to other fields and other uses.

Claims

1. Fluid handling apparatus comprising a first vessel defining a space for containing a fluid, a

^"second vessel containing a chamber which is for receiving fluid from said space in said first vessel and whose volume may be reduced to zero, and means for attaching said first vessel to said second vessel in a manner such that said fluid containing space may be contiguous with said chamber without any voids therebetween.

2. Apparatus according to claim 1, wherein said first vessel includes a movable member defining an extremity of said space, said movable member being movable from said first vessel into said second vessel when said vessels are connected together for creating said contiguous relationship between said space and said chamber.

3. Apparatus according to claim 2, wherein said movable member is a piston, said first vessel defining a cylinder in which said piston is movable and said second vessel defining, when connected to said first vessel, a continuation of said cylinder for receiving said piston.

4. Apparatus according to claim 1, wherein said chamber comprises a major portion whose volume is expansible from zero and is for containing said fluid upon completion of said transfer and a minor portion whose volume may be increased from zero for placing said major portion in communication with said space for effecting said transfer, said minor portion being such that its volume may be returned to zero after completion of said transfer in order to seal said fluid within said major portion.

5. Apparatus according to claim 4, wherein said minor portion of said chamber is defined by first and second elements which form a hermetic seal when said volume of said minor portion is at zero.

6. Apparatus according to claim 5, wherein said hermetic seal is formed by a solid metal ridge cooperating with a groove on first and second parts respectively.

7. Apparatus according to claim 4, wherein said major portion is defined by a piston and cylinder.

8. Apparatus according to claim 7, wherein said piston and cylinder defining said major portion are annular, a movable element for varying the volume of said minor portion defining the inner wall of said annular cylinder.

9. Apparatus according to claim 8, including a hydraulic jack and a nut for compressing said movable element.

10. Apparatus according to claiml, constructed to receive geological samples under high pressure.

11. A sampling vessel comprising a tube defining a space for receiving a sample, first and second members movable along said space relative to each other for increasing and decreasing the space between said numbers available for a sample, one of said members being movable out of said tube for placing the space between said members in communication with a further device to which said tube may be connected.

12. A device according to claim 11, wherein said first and second members are interconnected by a rod to which said one member is fixed and along which said other member is movable.

13. A device according to claim 12, including a detatchable end piece having a fluid inlet, said end piece being arranged to receive said one movable member so that said fluid inlet may be placed in communication with the space between said first and second members.

14. A transport vessel for fluid having a chamber therein whose volume is reducible to zero but which is expansible for receiving fluid, and including a connection means for receiving a portion of a further vessel, said connecting means being such that a fluid receiving space of said further vessel may be placed in direct communication with said expansible chamber.

15. A method of providing a geological sample comprising causing the sample to enter a sample receiving space in a sampling tool; connecting the sampling tool to a shipping vessel having a first space which may form a continuation of said space in said tool when said tool and said vessel are connected together and a second space whose volume is reducible to zero and which is directly contiguous with said first space; causing said first space to form said continuation with said space of said tool whilst said ^"second space is at zero volume; and increasing the volume of said second space from zero to transfer said sample to said second space.

16. A method according to claim 15, wherein said second space comprises a first portion remote from said first space and a second portion interconnecting said first portion with said first space, and wherein, upon completion of said transfer, the volume of said second portion is reduced to zero to form a hermetic seal to retain the sample in the first portion of said second space.

17. A shipping vessel for a geological sample having a first space for receiving a portion of the sampling tool, a second space whose volume is reducible to zero for storing a sample in the shipping vessel, and a passage which interconnects said first and second spaces and whose volume is reducible to zero for forming a hermetic seal between said first and second space, said first and second spaces being directly contiguous with said passage.