GB2349399A

GB2349399A - Apparatus and method for recovering drill cuttings

Info

Publication number: GB2349399A
Application number: GB9911630A
Authority: GB
Inventors: David Wood; Jonathan Charles Mears
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-04-26
Filing date: 1999-05-20
Publication date: 2000-11-01
Anticipated expiration: 2019-05-20
Also published as: GB9909515D0; GB2349399B; GB9911630D0

Abstract

An apparatus for recovering drill cuttings comprises a conduit (5), for example a riser, extending from an offshore installation with one end located in close proximity to the cuttings (11), and a pumping means which pumps the cuttings through the conduit (5). Additional conduits, such as flexible hoses (7a, 7b), may be connected to the end of the riser. The pumping means comprise a piston located within the riser and a lifting/lowering means coupled to an elongate member such as a drill pipe (9). A one way bypass means may be provided to allow cuttings and fluid to bypass the piston only as it is lowered into the riser. The bypass means may be a valve arrangement provided on or associated with the piston. A valve arrangement may be provided at the lower end of the riser which permits fluids and cuttings to ingress into the riser when the piston is moved upwards, but prevents such ingress when the piston is moved downwards. The piston may comprise a throughbore and a valve arrangement to obturate and open the throughbore. Drilling means may be provided at the end of hoses (7a, 7b).

Description

"Apparatus and Method For Recovering Drill Cuttings" The present invention relates to an apparatus and method for recovering drill cuttings, and particularly, but not exclusively, relates to the recovery to the surface of waste drilling muds and drill cuttings piles that are located beneath and around installations such as platforms and/or sub-sea production manifolds, in areas of the world such as the North sea, at a range of depths, which may be in the range from 100 metres to 250 metres.

Drill cuttings are a waste material, or spoil, taken out of wells drilled to explore, evaluate or produce oil and gas. Traditionally, drill cuttings from offshore installations have been disposed of by depositing them and allowing them to disperse through the water column and settle on the seabed in piles.

Other drilling waste, especially from top-hole sections that are drilled before risers are installed, are deposited directly on the seabed near the wellbore.

Licences from regulatory authorities have controlled this disposal.

Drilling muds are used to assist in drilling wells and provide various functions including lubricating the drill bit, transporting the drill cuttings produced by the drill bit to the deck of the installation and control of fluid pressure to maintain fluid equilibrium within the well bore and avoid uncontrolled releases of hydrocarbons. The types of base fluid used (water, diesel, mineral oil or a synthetic) and the chemical composition of these drilling muds may vary depending upon the individual well, and may change during the drilling of the well, for instance to maintain adequate downhole pressure by varying the density of the mud, and to cope with different rock types and angles of well.

In 1998 OSPAR issued the Sintra agreement which requires total removal of all fixed steel offshore production platforms with the possible derogation for larger platforms in excess of 10,000 Tonnes weight.

Many of these platforms, and in particular the larger platforms, have piles of drill cuttings, which may cover parts of the platform structure. It is likely that it will prove impossible to remove these platforms right down to the sea floor without disturbing the drill cuttings and potentially releasing the pile contents into the water column. Furthermore, access to the internal sections of the platform's steel jacket will be restricted by the existing cuttings piles which can be 10 metre high and spread over an area of 75 sq. metres.

Therefore, there is a requirement to be able to remove the drill cuttings from the sea bed. However, lifting these cuttings from the sea bed with existing proposed technology will prove time consuming and expensive.

The main thrust of the technology to date is to use seawater as a transport medium whereby for every tonne of drill cuttings/drilling muds recovered, it will be a requirement to treat up to 5 to 8 tonnes of oil contaminated seawater on the platform.

According to a first aspect of the present invention, an apparatus for recovering drill cuttings, the apparatus comprising a conduit which extends from an offshore installation, one end of the conduit being located in close proximity to the drill cuttings to be recovered, and a pumping means which pumps the drill cuttings through the conduit.

According to a second aspect of the present invention, a method of recovering drill cuttings, the method comprising providing a conduit which extends from an offshore installation with a pumping means, where one end of the conduit is in close proximity to the drill cuttings to be recovered, and operating the pumping means to pump the drill cuttings through the conduit.

The offshore installation may be an offshore platform, floating vessel, mobile (jack-up or semi-submersible) drilling rig or drill ship, or the like.

Preferably, one or more additional conduit (s) are connected to the said end of the first conduit at an inner end thereof, and typically it is the outer end of the said one or more additional conduits that is in close proximity to the drill cuttings to be recovered.

The pumping means may comprise a piston which is preferably located within one of the conduits, typically the first conduit. The pumping means may further comprise a means for moving the piston, where the means for moving the piston may comprise a lifting/lowering means coupled to one end of an elongate member, where the other end of the elongate member is coupled to the piston. Preferably, the lifting/lowering means is a draw works which is provided on the offshore vessel, and the elongate member is preferably one or more sections of drill pipe.

Typically, the lifting/lowering means is operated to lift the piston upwardly through the conduit. The invention has the advantage that the cuttings will be sucked into the conduit below the piston due to a vacuum being created therein. Furthermore, the deeper the lower end of the conduit, then the greater the sucking action, due to the hydrostatic pressure of the surrounding water acting upon the drill cuttings pile.

Typically, a bypass means is provided to permit fluid and/or cuttings to bypass the piston as the piston is lowered within the conduit. Preferably, the bypass means is a one way bypass means that only allows the fluid and/or drill cuttings to bypass the piston as it is lowered within the conduit.

Typically, the conduit is a riser, and the one or more additional conduits are suction hoses. Optionally, a liner is provided within the riser, and the piston is typically sealed with respect to the liner.

Preferably, the liner is formed from a material that has enhanced wearing properties.

The bypass means may be a valve arrangement which is preferably provided on, or associated with the piston.

Preferably, a packer is provided, where the packer can wipe the drill pipe, and can seal the annulus between the outer surface of the drill pipe and the inner surface of the riser/liner.

Preferably, a cuttings/fluid discharge port is provided in the riser, to permit the cuttings recovered from the seabed to exit the riser, and more preferably, a number of discharge ports are provided to permit the cuttings recovered from the seabed to exit the riser at different vertical locations into a respective number of systems for various treatment/disposal options.

Preferably, a valve arrangement is provided for the riser, and is typically located at the lower end thereof, the valve arrangement preferably being capable of permitting fluids and/or cuttings to ingress into the riser when the piston is moved upwardly within the riser, and typically further being capable of preventing fluids and/or cuttings from exiting through the lower end of the riser when the piston is moved downwardly through the riser.

Preferably, the lower end of the riser, or if present, the lower end of the suction hoses is/are provided with a grating which prevents unwanted objects from entering the riser/suction hoses. Optionally, a shaped conduit is provided at the lower end of the riser, or if present, suction hoses, to prevent unwanted objects from entering the riser/suction hoses. Typically, the piston is provided with a throughbore which is in fluid communication with the throughbore of the drill pipe, and preferably, a valve arrangement is provided which is capable of obturating and opening the throughbore of the piston. A pump may be coupled to the upper end of the drill pipe, and a flushing fluid may be pumped through the throughbore of the drill pipe, and the piston, and thereafter into the riser and, if required, the suction hoses. This has the advantage that any blockages that may occur while in operation of the pumping means can be effectively cleaned out, without having to recover the whole of the pumping means.

Preferably, a drilling means is provided, and which is operable to aid insertion of the suction hose into the material to be recovered, preferably into the centre thereof, which provides the advantage that the cuttings are recovered from the bottom of the piles in the first instance, thereby minimising the disturbance to the surface of the cuttings material. This action will also reduce to a minimum the recovery of the seawater column located on top of the cuttings material.

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 schematic side view of an offshore platform incorporating an apparatus and method in accordance with the present invention; Fig. 2 is a cross-sectional side view of a valve mechanism for use with the apparatus and method of Fig. 1; Fig. 3 is a cross-sectional side view of a portion of a piston assembly for use with the apparatus and method of Fig. 1; Fig. 4 is a cross-sectional side view of the piston assembly of Fig. 3 located within, and at the lower end of, a suction riser, with a valve mechanism of the piston assembly, and the valve mechanism of Fig. 2, configured for an upward stroke of the piston assembly; Fig. 5 is a cross-sectional side view of the piston assembly of Fig. 3 located within, and at the lower end of, a suction riser, with a valve mechanism of the piston assembly, and the valve mechanism of Fig. 2, configured for a downward stroke of the piston assembly; Fig. 6 (a) is a side view of an"S"shaped conduit for use with the apparatus and method of Fig. 1; Fig. 6 (b) is a plan view of the"S"shaped conduit of Fig. 6 (a); Fig. 6 (c) is a plan view of a"T"shaped conduit of use with the apparatus and method of Fig. 1; Fig. 6 (d) is a plan view of the'T"shaped conduit of Fig. 6 (c); Fig. 7 is a cross-sectional side view of a suction riser for use with the apparatus and method of Fig. 1; Fig. 8 is a cross-sectional side view of an alternative piston assembly to that shown in Fig.

3 for use with the apparatus and method shown in Fig. 1; and Fig. 9 is a plan view of an alternative valve mechanism to that shown in Fig. 2 for use with the apparatus and method of Fig. 1.

Fig. 1 shows the main components of a drill cuttings pumping assembly in accordance with the present invention. An offshore drilling rig is shown as comprising a derrick 1 which supports a conventional draw works 2 with a hook connecting the draw works to a length of drill pipe 9. The draw works has conventionally been used to lift and lower the drill string which is inserted into, and pulled from, the well when drilling operations are conducted.

A drilling riser 5 extends vertically downwardly from the drilling rig, passes through the surface of the sea 8 and has it's lower end located close to the seabed 10. However, in accordance with the present invention, and as will be detailed subsequently, the drilling riser is utilised as a suction riser 5.

A drilling module 3 is supported on a platform steel jacket 4 of the drilling rig, where the drilling module 3 houses a drive section (not shown) for a pump assembly, whose purpose will be detailed subsequently.

A pair of suction hoses 7a, 7b are coupled to the lower end of the suction riser 5 and are deployed both within and outwith the steel jacket 4. A piston 6 is located on the lower end of the drill pipe 9 within the suction riser 5.

Accordingly, activation of the drive section operates the draw works 2 to pull the drill pipe 9 upwardly within the suction riser 5. The piston 6 is consequently moved upwardly within the suction riser 5, and drill cutting piles 11 are sucked into the suction riser 5 below the piston 6.

Therefore, the main components as detailed above act to form a pump assembly for pumping drill cuttings 11 from the sea bed. The main components will now be described in more detail.

Fig. 2 shows a valve mechanism 12 which comprises a duel head non-return valve arrangement, where the valve mechanism 12 is located at the lower end of the suction riser 5. As stated, the valve mechanism 12 shown is a duel headed mechanism, but it should be noted that a single or multi-head mechanism could be used. Each head of the valve mechanism 12 is fitted with a pair of non-return flapper valves 14 but it should also be noted that any type of valve such as for instance hydraulically, mechanically, electrically or gravity actuated could be used. Suction ports 13 are provided at the lowermost end of the valve mechanism 12 to which the suction hoses 7a, 7b are attached. Accordingly, when the non-return flapper valves 14 are closed (in the arrangement shown in Fig. 2 they are closed when they are horizontal), drill cuttings 11 located in the suction hoses 7a, 7b are prevented from passing through the suction ports 13, and when the non-return flapper valves 14 are open (in the arrangement of the valves 14 shown in Fig. 2 they are open when they are substantially vertical), drill cuttings 11 located in the suction hoses 7a, 7b are permitted to pass through the suction ports 13 into the suction riser 5.

Referring now to Fig. 3, a piston assembly 16 is shown as comprising at least one, and as shown in Fig. 3, two non-return flapper valves 15, although it should be noted that any type of valve, such as for instance hydraulically, mechanically, electrically or gravity actuated could be used. A female pipe thread connection 19 is provided on the upper end of the piston assembly for coupling with the lower end of the drill pipe 9.

Each non-return flapper valve 15 is located immediately above a port 18 in the piston assembly 16, and the valve 15 is configured such that drill cuttings 11 are permitted to pass through the port 18 in the piston assembly 16 on the down stroke of the piston assembly 16, but will be restrained from passing through the port 18 on the up stroke of the piston assembly 16.

Hence, the piston assembly 16 can move through the column of drill cuttings located in the suction riser 5 on it's 16 down stroke, and will raise the column of drill cuttings above it 16 in the suction riser 5 and suck more drill cuttings from the pile 11 into the suction riser 11 below it 16 on its up stroke.

The piston assembly 16 also comprises a throughbore 30 which is in fluid communication with the throughbore of the drill pipe 9. A non-return valve 17 is provided at the lower end of the piston assembly 16, and is arranged such that the lower end of the non-return valve 17 normally protrudes from the lower end of the piston assembly 16. Thus, in this configuration, and as shown in Fig. 3, the non-return valve will normally obturate the lower end of the throughbore 30, thus preventing any fluid from passing therethrough.

However, if the piston assembly 16 is lowered within the suction riser 5 by a sufficient amount, then the non-return valve 17 will make contact with the upper surface of the valve mechanism 12. The non-return valve 17 will open and in this configuration of the non-return valve 17, seawater could be pumped down the drill pipe 9 by a single mud pump (not shown) to circulate and clean the components.

Fig. 4 shows the general arrangement of the pump assembly in accordance with the present invention. The piston assembly 16 incorporating the valves 15 is located in the suction riser 5 and the valve mechanism 12 incorporating the valves 14 is attached to the lower end of the suction riser 5, where the various valves 14,15,17 are shown as being configured during an upward stroke of the piston assembly 16.

Fig. 5 shows the general arrangement of the pump assembly, where the various valves 14,15,17 are shown as being configured during a downward stroke of the piston assembly 16.

Referring to Figs. 6 (a) and 6 (b), an"S"shaped conduit or pipe 32 may be located at the outermost end of the suction hose 7a, 7b to prevent ingression of long/thin objects such as scaffolding poles which could be located in the drill cutting pile 11 and could damage some of the valve and piston assemblies of the pump assembly. Alternatively, Figs. 6 (c) and (d) show a"T"shaped conduit or pipe 34 that could be attached to the outermost ends of the suction hose 7a, 7b for the same purpose. Preferably, the outermost ends of the suction hoses 7a, 7b, of the lower most ends of the "S"or"T"shaped conduits 32,34 are provided with a steel grid 35, which may have a mesh size with no more than a 70 mm aperture, to again prevent ingression of long/thin objects such as scaffolding poles which could be located in the drill cutting pile 11.

Fig. 7 shows the drilling/suction riser 5 being provided with a hardened chrome liner 19 at it's lower fitted, the liner being in the region of 120 ft long.

The liner is fitted within the internal bore of the suction riser 5, and is in a close fit thereto. It should be noted that any length of liner 19 could be installed within the suction riser 5, typically in 10ft or 20ft length sections. It should also be noted that any suitable material could be used for the liner 19, where the material preferably has good wear resistance properties. The drilling/suction riser total length is only limited by the number of sections of suction riser 5 connected together. The drill pipe 9 is normally supplied in lengths of 30 ft and screwed together into any required length. A flanged discharge pipe 20 is provided in the sidewall of the suction riser, preferably toward the upper end thereof, and is typically located in close proximity to a packer 21, which could be any suitable packer such as one of the packers provided by the HYDRIL COMPANY of Houston, Texas, USA. The packer 21 is installed for the purpose of wiping the drill pipe 9 clean and can be fully closed to allow high-pressure seawater flushing of any of the assembled components via the drill pipe 9 and the mud pump. Two or three of the flanged discharge pipes 20 could be attached to the suction riser sections 5 as they run through the different elevation of the drilling and production modules. Thus, cuttings can be discharged at different levels of the riser, whereby a number of treatment and disposal options could be located. It should be noted that if drilling riser is not available, any length of pipe with suitable structural strength and integrity could be used in it's place, and may or may not be fitted with a hardened liner 19.

Fig. 8 shows a floating piston assembly 36, which is an alternative to the piston assembly 16. This floating piston assembly 36 offers a method of opening and closing the equivalent piston ports 18 by having the non-return valves 25 provided below a floating piston ring 23. The floating piston ring 23 is located on, and is axially moveable with respect to, a cylindrical mounting 38, where the mounting 38 is preferably integral with the non-return valves 25. On the down stroke of the floating piston assembly 23, the floating piston ring 23 moves up against the retaining ring 22.

This allows a considerable clearance between, and no flow restriction through, the ports 18 in relation to the non-return valves 25. On the up stroke, the friction created between the piston seal 28 and the hardened chrome liner 19 will not allow movement of the floating piston ring 23 until the non-return valves 25 make contact with the piston ports 18. This action will close the piston ports 18 and upper surface loading on the floating piston ring 23 during the up stroke action will retain the piston ports 18 closed. A spring 24 will act as a damper on the upward stroke and will assist the floating piston 23 to move to the retaining ring 22 on the downward stroke. The cylindrical mounting 38 is provided with a similar non-return valve 17 as before, for the same purpose.

Fig. 9 shows a second example of a valve mechanism 40, which is either an alternative to the valve mechanism 12 of Fig. 2, or which can be bolted to the suction ports 13 of the valve mechanism 12 of Fig. 2, and if this latter situation is the case, the non-return flapper valves 14 are removed form the valve mechanism 12. The valve mechanism 40 has two hydraulically actuated ball valves 26 instead of the flapper valves 14 of the valve mechanism of Fig. 2. Suction ports 42 are provided at the lowermost end of the valve mechanism 40 to which the suction hoses 7a, 7b are attached.

The hydraulic actuators 27 will be connected by a hydraulic umbilical (not shown) and controlled from a panel (not shown) located on the drillers console (not shown) which in turn is located in the drilling module 3. This will allow for independent isolation of any of the suction ports 13 and suction hoses 7a, 7b. During normal operations any selected valves 26 will be automatically opened and closed by a respective limit switch (not shown). One limit switch located on the drill floor will open the valves 26 at the bottom of the downward stroke of the piston assembly 16 or 23, and a similar unit on the drilling derrick will close the valve at the top of the upward stroke of the piston assembly 16 or 23.

Therefore, the embodiments described herein provide a pumping system the uses a large proportion of the existing drilling package, thus reducing costs and overcoming limiting space restriction. This embodiment will effectively turn the assembled 120-ft length of the standard drilling riser 5 into a suction pump, and since the piston assembly 6 is attached to the draw works 2 of the drilling derrick 1 by means of drill pipe 9 and a Kelly hose (not shown), this will give an effective 100-ft stroke reciprocating suction pump.

The depth at which the pump could be deployed is only limited by the number of riser sections 5 added to the initial pump assembly and by the actual lifting capacity of the drilling derrick 1 and draw works 2 which can be 500 tonnes/cycle. Furthermore, with platform decommissioning, some or all of the original drilling slots will become available to deploy the drill cuttings recovery system and the drilling module would be skidded to the preferred location thus allowing its deployment anywhere within the existing platform structure 3,4. The deployment and recovery of the pumping assembly will not be weather dependent, as the pump will be deployed from the drill floor.

By attaching multiple suction hoses 7a, 7b to the multiple head non-return valve/ball valve arrangement located on the bottom of the modified drilling riser 5, drill cuttings 11 could be recovered from a number of locations 11 at the same time and this will allow for relocation of a single suction pipe assembly with the use of a Remotely Operated Vehicle (R. O. V.) without interrupting the ongoing recovery of drilling waste from other locations 11 around the platform steel jacket 4.

The embodiment described herein has the advantage in that the pumping system is located within the platform structure 3,4 but can effectively recover drill cuttings piles 11 located away from the platform structure 3,4 by deployment of a single or double suction hose 7a, 7b assembly.

In the case of drill cuttings piles located distal from the platform structure, a single or double suction hose 7a, 7b assembly will be deployed, where this deployment could be carried out by an R. O. V. or by a track mounted remotely controlled vehicle.

The recovery of the distal drill cuttings will be improved with the operational deployment depth of the drill cuttings recovery system. This is due to the incremental increase of the hydrostatic pressure of the surrounding seawater, which will provide a constant pressure acting on the cutting pile 11.

It is preferred that small hydraulically powered boring heads (not shown) or mechanical-rotating cutters (not shown) could be attached to the ends of the suction hose assemblies 7a, 7b, which can be operated to bury the suction hose 7a, 7b in the cutting piles 11, preferably into the centre thereof, thereby recovering the cuttings from the bottom of the piles 11 in the first instance and minimising the disturbance to the surface of the pile 11. This action will also reduce to a minimum the recovery of the seawater column located on top of the piles 11.

The inclusion of the drill pipe 9, a Kelly hose (not shown), BOP packer 21 and a mud pump will allow for the whole of the pumping system including the riser sections 5, pump assembly, multiple head non-return valve/ball valve arrangement 12 and multiple suction hoses 7a, 7b to be back flushed with clean seawater if required to clean out or remove any blockages that may occur while in operation, without having to recover the whole pumping assembly.

Due to the arrangement and location of the pumping system and suction riser 5, the embodiments allow for a number of discharge points 20 within the platform elevation to discharge recovered drilling mud/drill cuttings into a number of systems for various treatment/disposal options.

Moreover, with the drilling derrick and draw works being located at the highest point of the drilling module, a number of discharge points 20 could be attached to the riser assembly 5 within the platform elevation to discharge recovered drilling mud/drill cuttings into various treatment/disposal options.

A suction riser discharge point 20 in the lower elevation of the drilling/production module could be used to feed the waste into a conventional cutting re-injection system for disposal. A discharge point 20 on the middle elevation could be used for a conventional conveyor or panzer chain transfer system to discharge drilling waste directly into a boat, with the upper level discharge point being used to feed the drilling waste and any large volumes of seawater over the existing solids control equipment.

If the system was based on a 30"diameter drilling riser with 100 ft stroke it should be possible to recover over 20 tons of drilling mud and drill cuttings per stroke. If the stroke frequency is limited to fifteen strokes/hour it should be possible to recover up to 300 tons of waste material/hour with a minimal increase in the existing seawater content.

The apparatus and method herein described could also be used on a mobile (jack-up or semisubmersible) drilling rig or drill ship. It could also be deployed with a modified drill pipe lifting source, such as a hydraulic cylinder, which could be located on a dive support vessel (DSV).

Furthermore, the pumping system can be deployed within an existing platform structure and can be moved within that structure to any free or decommissioned production riser location that may become available with platform decommissioning. Additionally, the deployment, recovery and operation of the pumping system will not be weather dependent. Since the pumping system will be deployed from the drill floor, and uses existing riser guides to maintain its location, it can achieve this during high seas and storms. Furthermore drill cuttings and waste muds can be recovered from a number of locations 11 around the base of the platform steel jacket 4 or outwith the platform steel jacket 4 at the same time.

Modifications and improvements may be made to the embodiments described herein without departing from the scope of the invention.

Claims

CLAIMS: 1. An apparatus for recovering drill cuttings, the apparatus comprising a conduit which extends from an offshore installation, one end of the conduit being located in close proximity to the drill cuttings to be recovered, and a pumping means which pumps the drill cuttings through the conduit.
2. An apparatus according to claim 1, wherein one or more additional conduit (s) are connected to the said end of the first conduit at an inner end thereof, and it is the outer end of the said one or more additional conduits that is in close proximity to the drill cuttings to be recovered.
3. An apparatus according to either of claims 1 or 2, wherein the pumping means comprises a piston which is located within the conduit.
4. An apparatus according to claim 3, wherein the pumping means further comprises a means for moving the piston.
5. An apparatus according to claim 4, wherein the means for moving the piston comprises a lifting/lowering means coupled to one end of an elongate member, where the other end of the elongate member is coupled to the piston.
6. An apparatus according to claim 5, wherein the lifting/lowering means is a draw works which is provided on the offshore vessel.
7. An apparatus according to either of claims 5 or 6, wherein the elongate member is one or more sections of drill pipe.
8. An apparatus according to any of claims 5 to 7, wherein the lifting/lowering means is operated to lift the piston upwardly through the conduit.
9. Apparatus according to any of claims 5 to 8, wherein a bypass means is provided to permit fluid and/or cuttings to bypass the piston as the piston is lowered within the conduit.
10. Apparatus according to claim 9, wherein the bypass means is a one way bypass means that only allows the fluid and/or drill cuttings to bypass the piston as it is lowered within the conduit.
11. Apparatus according to any preceding claim wherein the conduit is a riser.
12. Apparatus according to any of claims 2 to 11 wherein the one or more additional conduits are suction hoses.
13. Apparatus according to claim 11 or to claim 12 when dependent on claim 11, wherein a liner is provided within the riser, and the piston is movably sealed with respect to the liner.
14. Apparatus according to either of claims 9 or 10, or to any of claims 11 to 13 when dependant on either of claims 9 or 10, wherein the bypass means is a valve arrangement which is provided on, or associated with, the piston.
15. Apparatus according to claim 7, or to any of claims 8 to 14 when dependant on claim 7, wherein a packer is provided, where the packer can wipe the drill pipe, and can seal the annulus between the outer surface of the drill pipe and the inner surface of the riser/liner.
16. Apparatus according to claim 11, or to any of claims 12 to 15 when dependant on claim 11, wherein a cuttings/fluid discharge port is provided in the riser, to permit the cuttings recovered from the seabed to exit the riser,
17. Apparatus according to claim 16, wherein a number of discharge ports are provided to permit the cuttings recovered from the seabed to exit the riser at different vertical locations into a respective number of systems for various treatment/disposal options.
18. Apparatus according to claim 11, or to any of claims 12 to 17 when dependant on claim 11, wherein a valve arrangement is provided for the riser, located at the lower end thereof, the valve arrangement being capable of permitting fluids and/or cuttings to ingress into the riser when the piston is moved upwardly within the riser, and further being capable of preventing fluids and/or cuttings from exiting through the lower end of the riser when the piston is moved downwardly through the riser.
19. Apparatus according to claim 7, or to any of claims 8 to 18 when dependant on claim 7, wherein the piston is provided with a throughbore which is in fluid communication with the throughbore of the drill pipe.
20. Apparatus according to claim 19, wherein a valve arrangement is provided which is capable of obturating and opening the throughbore of the piston.
21. Apparatus according to either of claims 19 or 20, wherein a pump is coupled to the upper end of the drill pipe, and a flushing fluid may be pumped through the throughbore of the drill pipe, and the piston, and thereafter into the riser and, if required, the suction hoses.
22. Apparatus according to any preceding claim, wherein a drilling means is provided, and which is operable to aid insertion of the conduit into the material to be recovered.
23. A method of recovering drill cuttings, the method comprising providing a conduit which extends from an offshore installation with a pumping means, where one end of the conduit is in close proximity to the drill cuttings to be recovered, and operating the pumping means to pump the drill cuttings through the conduit.
24. A method according to claim 23, wherein one or more additional conduit (s) are connected to the said end of the first conduit at an inner end thereof, and it is the outer end of the said one or more additional conduits that is in close proximity to the drill cuttings to be recovered.
25. A method according to either of claims 23 or 24, wherein the pumping means comprises a piston located within one of the conduits.
26. A method according to claim 25, wherein the pumping means further comprises a means for moving the piston.
27. A method according to claim 26, wherein the means for moving the piston comprises a lifting/lowering means coupled to one end of an elongate member, where the other end of the elongate member is coupled to the piston.
28. A method according to claim 27, wherein the lifting/lowering means is a draw works which is provided on the offshore vessel.
29. A method according to either of claims 27 or 28, wherein the elongate member is one or more sections of drill pipe.
30. A method according to any of claims 27 to 29, wherein the lifting/lowering means is operated to lift the piston upwardly through the conduit.
31. A method according to any of claims 27 to 30, wherein a bypass means is operable to permit fluid and/or cuttings to bypass the piston as the piston is lowered within the conduit.
32. A method according to claim 31, wherein the bypass means is a one way bypass means that only allows the fluid and/or drill cuttings to bypass the piston as it is lowered within the conduit.
33. A method according to any of claims 23 to 32 wherein the conduit is a riser.
34. A method according to any of claims 24 to 33 wherein the one or more additional conduits are suction hoses.
35. A method according to either of claims 33 or 34 wherein a liner is provided within the riser, and the piston is movably sealed with respect to the liner.
36. A method according to either of claims 31 or 32, or to any of claims 33 to 35 when dependant on either of claims 31 or 32, wherein the bypass means is a valve arrangement which is provided on, or is associated with, the piston.
37. A method according to claim 29, or to any of claims 30 to 36 when dependant on claim 29, wherein a packer is provided, where the packer is operable to wipe the drill pipe, and is operable to seal the annulus between the outer surface of the drill pipe and the inner surface of the riser/liner.
38. A method according to claim 33, or to any of claims 34 to 37 when dependant on claim 33, wherein a cuttings/fluid discharge port is provided in the riser, to permit the cuttings recovered from the seabed to exit the riser,
39. A method according to claim 38, wherein a number of discharge ports are provided to permit the cuttings recovered from the seabed to exit the riser at different vertical locations into a respective number of systems for various treatment/disposal options.
40. A method according to claim 33, or to any of claims 34 to 39 when dependant on claim 33, wherein a valve arrangement is provided at the lower end of the riser, the valve arrangement being capable of permitting fluids and/or cuttings to ingress into the riser when the piston is moved upwardly within the riser, and further being capable of preventing fluids and/or cuttings from exiting through the lower end of the riser when the piston is moved downwardly through the riser.
41. A method according to claim 33, or to any of claims 34 to 40 when dependant on claim 33, wherein the piston is provided with a throughbore which is in fluid communication with the throughbore of the drill pipe.
42. A method according to claim 41, wherein a valve arrangement is provided which is operable between a first configuration in which the throughbore of the piston/drill pipe is obturated, and a second configuration in which the throughbore of the piston/drill pipe is open.
43. A method according to either of claims 41 or 42, wherein a pump is coupled to the upper end of the drill pipe and is operable to pump flushing fluid through the throughbore of the drill pipe, and the piston, and thereafter into the riser and, if required, the suction hoses.
44. A method according to any preceding claim, wherein a drilling means is provided, and which is operable to aid insertion of the conduit into the material to be recovered.
45. An apparatus substantially as hereinbefore described, with reference to the accompanying drawings.
46. A method substantially as hereinbefore described, with reference to the accompanying drawings.