CORE BARREL VALVE ASSEMBLY

- ATLAS COPCO CANADA INC.

A valve assembly for use in an inner tube member of a core barrel head assembly positionable within a drill string of a drilling apparatus. The valve assembly works using two separate surfaces A and B and a biasing element with a force FS. When hydrostatic pressure is present forces are created on these surfaces: FA and FB. These forces have a direct relationship with pressure, as an increase in pressure will increase the force and vice versa. The surface areas are designed such that: FA>FB+FS, which will maintain the valve closed while under a predetermined fluid pressure, indicating to the driller that the inner tube has landed. When the driller relieves the fluid pressure and the pressure decreases, the force difference between FA, FB and FS decreases until FA<FB+FS, thus opening the valve for drilling.

Skip to: Description  ·  Claims  · Patent History  ·  Patent History
Description
FIELD OF THE INVENTION

The present invention generally relates to core barrels. More specifically, it relates to a core barrel head assembly.

BACKGROUND OF THE INVENTION

It is known in various connections to use valves that control the supply of a fluid by being opened when they are subjected to a certain pressure from the fluid. One such application is in wire line core drilling, as will be described below.

When performing exploratory drilling to collect rock samples from depths of from several hundred to a couple of thousand meters, double core tubes are used having an inner and an outer tube. The sample is collected in the inner tube, which usually has a length of a few meters. When the inner tube is full this is usually detected by means of a manometer or the like that measures the flushing water pressure in the core tube. A retriever device suspended on a wire is lowered into the tube for retracting the inner tube with the sample, said retriever device comprising a gripping means in the form of a claw or “spearhead” arranged to engage with a gripping means arranged on/in the upper end of the inner tube. When the wire is then tautened the inner tube is disengaged from the outer tube, and the inner tube with the sample can be hoisted up. Conversely, the claw and the gripping means on the inner tube can be used to lower a new inner tube. Equipment of this type is generally known as a wire line system.

When a new inner tube is inserted it is important to be able to ascertain that the inner tube really has reached right down to the bottom of the outer tube and has assumed its correct position for drilling, before drilling is commenced. Ascertainment that the tube can no longer move, but is firmly held is generally taken as an indication that the inner tube has reached its correct position. According to known technology, therefore, the gripping means is often designed to be combined with some type of locking member that firmly locks the inner tube in relation to the outer tube when the inner tube has reached the correct position. This locking member usually consists of a hook-like device, preferably spring-loaded, a locking claw or latch that engages with recesses or shoulders arranged in the inside of the outer tube. Actual insertion of the inner tube is usually performed by the inner tube being “pumped” along inside the drill string with the aid of water. When the inner tube is firmly in place the water pressure will increase to such an extent that a valve arranged for flushing medium in the inner tube is released.

One problem with such known arrangements is that when the inner tube is inserted into the drill string it sometimes catches before it has reached the correct position for drilling. With designs currently in use, the increase in water pressure then occurring will release the flushing valve before the inner tube has reached its correct position and, in the worst case, drilling will be commenced. This primarily entails a disadvantage from the financial point of view since the drilling will be into thin air. There is also a risk of the core at the bottom being destroyed. Hence it is useful to provide a landing indicator system in order to ensure that the inner tube has reached its correct position.

The current industry standard to provide a landing indicator system uses a ball and bushing or plunger (ball attached to retracting case) and bushing as a valve assembly with short signal duration.

The current standard for a core barrel valves has a pressure signal that is very short in duration and can be easily missed by the driller and is not reliable on deeper holes and requires frequent replacement. Previously known valves with sustained pressure signals were not reliable due to mud and debris jamming the moving parts of the valve. Previous valves also were limited in hole conditions with a very low water table and very deep holes, as they could not cope with the large differences in hydrostatic pressure.

The system described in U.S. Pat. No. 6,708,784 attempted to remedy some of the above-described problems. U.S. Pat. No. 6,708,784 discloses method for a valve, the valve comprising a movable valve element having a first side facing a means for supplying pressurized fluid and influenced in the supply direction by a force from said fluid, and a second side influenced in opposite direction by a force from said fluid. The valve is provided with at least one connection connecting the first side of the valve element with the second side of the valve element, and also comprises a spring for opening the valve by displacing the valve element from a closed position to an open position. The method comprises the following steps: a pressurized fluid is supplied to the valve in the closed position so that the valve remains closed; the supply of pressurised fluid to the closed valve ceases, a pressure force differential then decreases between the first and second sides thereby enabling the spring to open the valve, and a pressurized fluid is supplied to the valve in the open position and the valve remains open.

However, the valve assembly described in U.S. Pat. No. 6,708,784 is not self-resetting and does not function properly when debris and/or additives are present in the flushing medium.

Consequently, there is still presently a need for a valve assembly for a landing indicator system that is self-resetting and that will work with debris and/or additives in the flushing medium, while functioning properly in low water level conditions and in shallow holes.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a valve assembly that addresses at least one of the above-mentioned needs.

Accordingly, the present invention provides a valve assembly for use in a core barrel head assembly positionable within a drill string of a drilling apparatus, the valve assembly comprising:

    • a landing shoulder;
    • at least one upstream fluid flow port positionable within a fluid line of the drilling apparatus upstream of the landing shoulder;
    • at least one downstream fluid flow port positionable within the fluid line of the drilling apparatus downstream of the landing shoulder;
    • at least one fluid pressure communication port positionable within the fluid line of the drilling apparatus;
    • a movable valve element having a first side in fluid communication with pressurized fluid through the at least one pressure port and having a first surface that is influenced in the supply direction by a force FA from said fluid, and a second side facing in the opposite direction, in fluid communication with pressurized fluid through the at least one upstream fluid flow port and having a second surface that is influenced in the opposite direction by a force FB from said fluid;
    • at least one biasing element for opening the valve assembly by displacing the valve element from a closed position to an open position,
      wherein the area of said second surface is greater than that of said first surface so that the force influencing the valve element in a closing direction, in the form of the force FB from the pressurized fluid acting on said second surface exceeds the force influencing the valve element in an opening direction, in the form of the combined force Fs from the biasing element and the force FA from the pressurized fluid acting on said first surface, whereby the valve element is retained in the closed position of the valve when pressurized fluid is supplied.

According to the present invention, there is also provided a method for operating a valve assembly for use in a core barrel head assembly positionable within a drill string of a drilling apparatus driven by pressurized fluid, the valve assembly comprising:

    • a landing shoulder;
    • at least one upstream fluid flow port positionable within a fluid line of the drilling apparatus upstream of the landing shoulder;
    • at least one downstream fluid flow port positionable within the fluid line of the drilling apparatus downstream of the landing shoulder;
    • at least one fluid pressure communication port positionable within the fluid line of the drilling apparatus;
    • a movable valve element having a first side in fluid communication with pressurized fluid through the at least one pressure port and having a first surface that is influenced in the supply direction by a force FA from said fluid, and a second side facing in the opposite direction, in fluid communication with pressurized fluid through the at least one upstream fluid flow port and having a second surface that is influenced in the opposite direction by a force FB from said fluid;
    • at least one biasing element for opening the valve assembly by displacing the valve element from a closed position to an open position,
    • wherein the area of said second surface is greater than that of said first surface so that the force influencing the valve element in a closing direction, in the form of the force FB from the pressurized fluid acting on said second surface exceeds the force influencing the valve element in an opening direction, in the form of the combined force Fs from the biasing element and the force FA from the pressurized fluid acting on said first surface,
      the method comprising the steps of:
    • a) supplying the pressurized fluid to the valve element in its closed position whereupon the valve assembly remains closed;
    • b) reducing the supply of pressurized fluid to the closed valve assembly; and
    • c) allowing a pressure force differential to decrease between said first and second sides, thereby enabling the biasing element to urge the valve element towards the open position, and thereby allowing fluid flow through the at least one upstream fluid flow port.

In accordance with the present invention, there is also provided wire line core drill system comprising a wire line core drill having an inner tube by means of which core samples are collected, an outer tube connected to a drill bit, and a valve assembly situated at the rear end of the inner tube, the valve assembly controlling the supply of a flushing medium in the form of a pressurized fluid, wherein the valve assembly is constructed as described above.

The valve assembly according to the present invention provides two separate ports upstream of the landing shoulder and allowing fluid pressure to apply a force on two different surfaces eliminating small fluid passages that are prone to blockage from debris and allowing for significantly less restricted flow for drilling when the valve is open. Fluid pressure can be required to lock the latches engaged in the drill string. This ensures that the valve assembly will remain closed when the head has landed but fluid pressure has not yet built up. This feature also greatly decreases the pressure applied by the latches to the inside wall of the drill string while it is travelling down the drill string, greatly reducing the friction, decreasing wear on the latches and decreasing the time to travel to the bottom of the hole. The valve assembly can thus function in low water level conditions and in shallow holes.

The valve assembly according to certain embodiments of the present invention can also be self-resetting, a feature not present in the system described in U.S. Pat. No. 6,708,784. The system described in U.S. Pat. No. 6,705,784 would also not function properly when debris was present between sliding surfaces of the valves. However, the valve assembly according to the present also provides a reduced sliding surface area with seals added to block debris from entering these areas.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the detailed description of the preferred embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, which are diagrammatic, embodiments that are presently preferred. It should be understood, however, that the present invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

FIG. 1 is an exploded view of a head assembly according to a preferred embodiment of the present invention, with interchangeable mid latch bodies.

FIGS. 2A to 2C are cross-sectional side views of a head assembly according to another preferred embodiment of the present invention.

FIGS. 3A to 3C are detailed cross-sectional side views of the head assembly corresponding to the views shown in FIGS. 6A to 6C, illustrating flow streamlines through the valve assembly.

FIGS. 4A to 4D are partial detailed cross-sectional side views of the head assembly with a valve assembly according to another preferred embodiment of the present invention, illustrating a preferred sequential use of the valve assembly.

FIGS. 5A and 5B are partial side views of an upper latch body and latch retracting case of the head assembly shown in FIGS. 6A to 6C.

FIGS. 6A and 6B are a partial cross-sectional view of a valve assembly and partial side view of a joined upper latch body and latch retracting case, respectively, of the head assembly shown in FIGS. 6A to 6C, during a descent phase of a preferred sequential use of the valve assembly.

FIGS. 7A and 7B are a partial cross-sectional view of a valve assembly and partial side view of a joined upper latch body and latch retracting case, respectively, of the head assembly shown in FIGS. 6A to 6C, during a signal phase of a preferred sequential use of the valve assembly.

FIGS. 8A and 8B are a partial cross-sectional view of a valve assembly and partial side view of a joined upper latch body and latch retracting case, respectively, of the head assembly shown in FIGS. 6A to 6C, during a working phase of a preferred sequential use of the valve assembly.

FIGS. 9A and 9B are a partial cross-sectional view of a valve assembly and partial side view of a joined upper latch body and latch retracting case, respectively, of the head assembly shown in FIGS. 6A to 6C, during a transition to the retracting/retrieval phase of a preferred sequential use of the valve assembly.

FIGS. 10A and 10B are a partial cross-sectional view of a valve assembly and partial side view of a joined upper latch body and latch retracting case, respectively, of the head assembly shown in FIGS. 6A to 6C, during a retracting/retrieval phase of a preferred sequential use of the valve assembly.

 PREFERRED EMBODIMENTS OF THE PRESENT INVENTION

Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings and are thus intended to include direct connections between two members without any other members interposed therebetween and indirect connections between members in which one or more other members are interposed therebetween. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. Additionally, the words “lower”, “upper”, “upward”, “down” and “downward” designate directions in the drawings to which reference is made. The terminology includes the words specifically mentioned above, derivatives thereof, and words or similar import.

Referring now to the drawings in detail, wherein like numbers are used to indicate like elements throughout, there is shown in FIG. 1 an exploded view of a presently preferred embodiment of an core barrel head assembly 10 for a drilling apparatus.

The core barrel head assembly 10 is positionable within a drill string of a drilling apparatus. The core barrel head assembly 10 comprises an upper latch body 12 and a lower latch body 14. The head assembly 10 further comprises a mid latch body 16 separating the upper latch body 12 from the lower latch body 14 and removably coupling the upper latch body 12 to the lower latch body 14. FIG. 1 shows three different sample embodiments of the mid latch body 16A, 16B, 16C to illustrate the interchangeability of the mid latch body 16. In all cases, the mid latch body 16 is removably coupled to the upper latch body 12 and the lower latch body 14. The mid latch body 16 houses a landing indicator device 18. A common central bore 20 is formed by the upper latch body 12, the lower latch body 14 and the mid latch body 16.

Preferably, as illustrated in FIG. 1, the head assembly includes an upper latch body 12 with a latching assembly 30 and fluid pressure communication ports 32. The lower latch body 14 holds a landing shoulder 34 by a removable sleeve 36 and includes fluid flow ports 38 downstream of the landing shoulder. The mid latch body component 16 also has fluid flow ports 40 upstream of the landing shoulder, and connects the upper and lower latch bodies, 12,14, with a central bore 20 connecting the fluid flow ports 38,40. The mid latch body 16 contains a valving mechanism 42 which can provide a landing indication signal. The common central bore 20 is present through all body components. The head assembly preferably includes of two sets of ports: the first set for fluid pressure communication with the internal valving mechanism 42, the second set for fluid flow required for drilling in which the fluid flow is blocked or opened by the internal valving mechanism 42. This fluid port design offers the advantages of increased fluid flow during drilling which means it is less likely to collect debris and pack with mud and thus results also in a more efficient pumping system, compared to a head assembly where all the fluid circulates through a single port system upstream of the landing shoulder (thus more subject to blockage) from the upper latch body to the lower latch body, with no bypass port. Given the reconfigurable nature of the head assembly, different valving systems can be used depending on drilling conditions and also can be easily upgraded when a newer type of valve is developed. FIG. 1 illustrates an example of three different head assemblies in which the upper 12 and lower 14 latch bodies are similar and could be shared, but where a changeout of the mid latch body 16 allows the use of different valving mechanism designs that can be tailored to a specific drilling condition.

The following sections will illustrate different valving mechanisms that can be changed out through different mid latch bodies 16 while also benefiting from the advantages of having the distinct fluid pressure communication ports 32 and fluid flow ports 40 upstream of the landing shoulder.

Fluid Controlled Valves

FIG. 2A-10B show different embodiments of a head assembly in accordance with another preferred embodiment of the present invention. Once again, the head assembly allows for an interchangeable mid latch body 16 between an upper latch body 12 and a lower latch body 14. Also, the valving assembly in the mid latch body benefits from the use of separate pressure communication ports 32 and fluid flow ports 40. The head assembly includes a valve assembly 100 for use in a core barrel head assembly 10 positionable within a drill string of a drilling apparatus. The valve assembly 100 comprises at least one pressure port 32 formed in a sidewall of the core barrel head assembly 100 upstream of the landing shoulder. There is also at least one fluid flow port 40 formed in the sidewall of the core barrel head assembly 100 upstream of the landing shoulder. The valve assembly 100 also includes a movable valve element 218 having a first side 220 in fluid communication with pressurized fluid through the head assembly and having a first surface that is influenced in the supply direction by a force FA from said fluid. A second side 222 faces in the opposite direction, in fluid communication with the pressurized fluid through the head assembly and having a second surface that is influenced in the opposite direction by a force FB from the fluid. A biasing element, such as a spring 224 or any equivalent resilient element is provided for urging the valve assembly towards an opened configuration by displacing the valve element 218 from a closed position, blocking the at least one fluid flow port 40, to an open position. The biasing element or spring may be designed to be adjustable

The area of the second surface is greater than that of the first surface so that the force influencing the valve element 218 in a closing direction, in the form of the force FB from the pressurized fluid acting on the second surface exceeds the force influencing the valve element in an opening direction, in the form of the combined force Fs from the spring and the force FA from the pressurized fluid acting on the first surface, whereby the valve element is retained in the closed position of the valve when pressurized fluid is supplied, as illustrated in FIGS. 2A and 3A

Preferably, upon a reduction in the supply of pressurized fluid to the closed valve, the pressure force differential decreases between said first and second sides 220,222, and the spring 224 then urges the valve element 218 to be displaced from its closed position to its open position unblocking the at least one fluid flow port 40 as shown in FIGS. 2B and 3B.

Preferably, the valve assembly further comprises a locking device for mechanically locking the valve element in its closed position. In one possible embodiment illustrated in FIG. 4A to 4D, the locking device comprises a pressure sleeve 226 mechanically connected through the retracting case 28 to a latch locking mechanism 232 of the inner tube member. Another possible embodiment of the locking device is illustrated in FIG. 2A to 3C and FIG. 5A-10B and will be described in further detail below.

According to the present invention, there is also provided a method for operating the valve assembly for use in a core barrel head assembly positionable within a drill string of a drilling apparatus driven by pressurized fluid, the method comprising the steps of:

    • a) supplying the pressurized fluid to the valve element 218 in its closed position whereupon the valve assembly remains closed;
    • b) reducing the supply of pressurized fluid to the closed valve assembly; and
    • c) allowing a pressure force differential to decrease between the first and second sides 220,222, thereby enabling the biasing means 224 to urge the valve element 18 towards the open position, and thereby allowing fluid flow through the at least one fluid flow port and remain open.

Preferably, when the valve assembly 100 further comprises a locking device for mechanically locking the valve element in its closed position, in step a), the valve element is in a mechanically locked closed position, and the method further comprises the step, between steps a) and b) of:

    • i) causing the locking device to cease locking the valve element 218 in the closed position.

Preferably, the locking device comprises a pressure sleeve 226 mechanically connected to a latch locking mechanism 232 of the head assembly and step i) further comprises the step of allowing fluid pressure to displace the pressure sleeve 226 and engage a latch lock 228 of the latch locking mechanism 232.

As mentioned above, another embodiment of the fluid controlled valve assembly, and in particular the locking device, illustrated in FIG. 2A-3C and 5A-10B, will now be presented. Preferably, the valve element is a two-piece valve comprising a valve body 250 and a valve piston 252. The valve body 250 is used to selectively block the fluid flow port 40 and includes a side 222 which applies a force to urge the valve assembly towards a closed configuration. The valve piston 252 includes a side 220 which applies a force to urge the valve assembly towards an open configuration, The valve piston 252 further comprises a slotted stem 254 to allow fluid flow to flush debris and a pin 256 to co-operate with the profiled slots in the upper latch body 12 and latch retracting case 28 to be able to selectively lock the valve assembly in a closed configuration.

Preferably, as better shown in FIG. 5A the upper latch body 12 comprises a profiled slot 258 to co-operate with the pin 256 of the valve piston 252 to lock the valve-in the closed position and allow the valve to move to the open position after a predetermined rise in fluid pressure. More specifically, the profiled slot 258 allows axial movement of the pin within the main slot portion 260. A top end 262 of the slot 258 extends at an angle transversely with respect to the main slot portion, at least partially radially and towards the opposite bottom end to prevent the pin 256 from moving downward. The pin 256 is held in the radially extended slot position by the spring 224 that biases the valve assembly towards the open position.

Preferably, as the fluid pressure rises and the force on the surface of side 220 overcomes the spring force, both valve body 250 and piston 252 will move up and the pin 256 on the valve piston 252 will be directed by the angled slot extension 262 to move the pin 256 radially (or rotate it) towards the main slot portion 260 to allow for axial movement of the pin and hence the valve member when the pressure is released.

Preferably, as shown in FIG. 5B, the latch retracting case 28 also has a profiled slot 270 to cooperate with the pin 256 on the valve piston 252. The latch retracting case 28 automatically moves the pin 256 to the locked position on the profiled slot 258 of the upper latch body 12 when the latches 142 are retracted. The profiled slot thus helps to hold the latch retracting case 28 and latch lock in an intermediate up position such that the latch lock is not engaged to the latches 142, greatly reducing the latch drag on the drill rod during descent.

The profiled slot 270 allows for axial movement of the pin 256 within a main slot portion 272. A bottom end 274 of the slot extends at an angle with respect to the main slot portion 272, at least partially radially and axially lower than the main slot portion 272, thus rotating the pin 256 towards the locked position in the upper latch body 12 when the latch retracting case 28 is moved up to retract the latches 142. The pin 256 during the latch retraction can then extend back towards the bottom end 274 in a direction parallel to the main slot.

Preferably, when released from the overshot and during descent, the biasing means 280, such as a spring or other equivalent resilient element, in the retracting case 28 will bias the retracting case 28 towards the down position. The bottom end portion 274 of the profiled slot 270 will prevent the retracting case 28 from moving to the fully down position as it is being held in an intermediate up position, preventing the latch lock from engaging with the latches 142, once again greatly reducing the latch drag on the drill rod during descent.

An operational sequence of the valve assembly will now be described. Reference will be made to components illustrated in the two different groups of embodiments illustrated respectively in FIG. 2A to 3C/5A to 10B and FIG. 4A to 4D.

Descent

Before inserting the inner tube head assembly in the drill string, the latch retracting case 28 is pulled up (right side in FIG. 2A, 4A or 6A) to its first position. This will disengage the latch lock 228 and allow the latches 142 to move freely from the engaged position to the retracted position and vice versa. The valve biasing means 224 and retracting case biasing means 236 are compressed. In the embodiment shown in FIG. 4A, the latch retracing case 28 is directly connected to the pressure sleeve 226. The pressure sleeve 226 and/or the latch retracting case 28 are held in this first position (with a mechanical lock) as it is travelling through the drill string, to reduce the latch drag on the drill rod during descent. In the embodiment shown in FIG. 2A or 6A-6B, the pin 256 attached to the valve piston 252 is constrained through interaction with profiled slots 258, 270 and thus prevented from moving down to lock the latches 142, thereby reducing latch drag on the drill rod. The valve body 250 blocks fluid flow through the fluid flow port 40.

Signal

When the head assembly 10 has landed in the correct position, for the embodiment shown in FIG. 4B, fluid pressure will increase and act on the surface 220 and push with a force at a first predetermined value less than a second predetermined value, such as for example, maximum pump pressure, to move the pressure sleeve 226 down and engage the latch lock 228 with which it is directly connected through the latch retracting case 28. In this configuration, the latches 142 are engaged and locked into the outer tube and the valve element 218, which is connected to the retracting case 28 by slot 242 is allowed to operate normally. If the latches 142 are not in the correct position, the latch lock 228 and its directly connected components will not be able to move down to the second position and allow the valve to operate normally. Fluid pressure will remain high even after it has been released to the atmosphere, indicating to the driller that the latches are not properly engaged and corrective action must be taken. In the second position, the fluid pressure continues to rise and acts on first surface 220 through pressure communication port 32 and second surface 222 through fluid flow port 38. The first surface area is smaller than the second surface area such that when fluid pressure is present, the force generated by the second surface area is greater than the combined force generated by the first surface area and the force of the spring 224. This will maintain the valve in the closed position while fluid pressure is acting on the valve.

For the embodiment shown in FIG. 7A-7B, under similar fluid pressure conditions, the increased pressure will displace the valve body 250 and valve piston 252 up, which through interaction with the profiled slots 258,260, induces rotation of the pin 256 out of its locked configuration. This permits the valve piston 252 to move and allows the retracting case 28 to descend while the latches 142 become engaged. However, if the latches 142 are jammed, the retracting case 28 will not move down, thus blocking movement of the valve 252 piston and valve assembly and preventing opening of the fluid flow port 40.

Working

For the embodiment shown in FIG. 4C, when the fluid pump is stopped and the pressure is relieved, a pressure force differential decreases between the first and second surfaces 220,222 so that the biasing means 224 or spring force will move the valve element 218 down to an open, third position. The pump will then be turned back on and drilling fluid will flow freely through fluid flow port 40 to the drill bit for drilling.

For the embodiment shown in FIGS. 2B and 8A, 8B, once fluid pressure is relieved, the biasing means 224 or spring force also overcomes the pressure force differential between the first and second surfaces 220,222 to urge the valve element 218 towards an open position. In this configuration, fluid flows through the slots in the valve piston 254 and through the valve body 250 into the central bore 20.

Retracting/Retrieval

When the inner tube is full of core, the retrieval device or overshot is sent down the drill string and connects to the spearhead 50. For the embodiment shown in FIG. 4D, the spearhead 50, which is connected to the retracting case 28 is pulled up for retrieval and moves the retracting case 28 up past the first position it had during descent to its fourth position. The valve element 218 and valve body 250, being slideably connected to the retracting case 28, is moved up past the first position as well to allow fluid to flow through the apertures 260. When the overshot is disconnected from the spearhead 50, the spring 236 will return the valve assembly to the first descent position and it will be ready for the next trip down the hole.

For the embodiment shown in FIGS. 2C and 9A-9B, under similar conditions, retraction of the retracting case 28, induces rotation of the pin 256 towards a locked configuration thus keeping the latches 142 in an unlatched configuration and minimize drag of the latches on the drill rod during retrieval of the spearhead 50. This configuration also positions the valve body 250 in a configuration which keeps the fluid flow port 40 open during the retrieval operation.

Reset

For the embodiment shown in FIG. 10A-10B, once the valve assembly is returned to the surface, the valve body 150 must be displaced manually at the surface location in order to position the valve body 150 in a closed configuration that will be ready once again for the next descent down the hole. For the embodiment shown in FIGS. 4A-4D, the reset can be done automatically.

The present invention also provides a wire line core drill system comprising a wire line core drill having an inner tube by means of which core samples are collected, an outer tube connected to a drill bit, and a valve assembly situated at the rear end of the inner tube, said valve assembly controlling the supply of a flushing medium in the form of a pressurized fluid, wherein the valve assembly is constructed as described in one of the embodiments provided above.

Although preferred embodiments of the present invention have been described in detail herein and illustrated in the accompanying drawing, it is to be understood that the invention is not limited to these precise embodiments and that various changes and modifications may be effected therein without departing from the scope of the present invention.

Claims

1. A valve assembly for use in a core barrel head assembly positionable within a drill string of a drilling apparatus, the valve assembly comprising:

a landing shoulder;
at least one upstream fluid flow port positionable within a fluid line of the drilling apparatus upstream of the landing shoulder;
at least one downstream fluid flow port positionable within the fluid line of the drilling apparatus downstream of the landing shoulder;
at least one fluid pressure communication port positionable within the fluid line of the drilling apparatus;
a movable valve element having a first side in fluid communication with pressurized fluid through the at least one pressure communication port and having a first surface that is influenced in the supply direction by a force FA from said fluid, and a second side facing in the opposite direction, in fluid communication with pressurized fluid through the at least one upstream fluid flow port and having a second surface that is influenced in the opposite direction by a force FB from said fluid;
at least one biasing element for opening the valve assembly by displacing the valve element from a closed position to an open position,
wherein the area of said second surface is greater than that of said first surface so that the force influencing the valve element in a closing direction, in the form of the force FB from the pressurized fluid acting on said second surface exceeds the force influencing the valve element in an opening direction, in a form of combining a force Fs from the biasing element and the force FA from the pressurized fluid acting on said first surface, whereby the valve element is retained in the closed position of the valve when pressurized fluid is supplied and wherein the at least one fluid pressure communication port and the at least one upstream fluid flow port form two sets of ports, the first set for fluid pressure communication with the movable valve element, and the second set for fluid flow required for drilling in which the fluid flow is blocked or opened by the movable valve element.

2. The valve assembly according to claim 1, wherein, upon a reduction in the supply of pressurized fluid to the closed valve, a pressure force differential decreases between said first and second sides, and the biasing element then urges the valve element to be displaced from said closed position to said open position.

3. The valve assembly according to claim 1, further comprising:

a locking device for mechanically locking the valve element in its closed position.

4. The valve assembly according to claim 3, wherein the locking device comprises a pressure sleeve mechanically connected to a latch locking mechanism of the inner tube member.

5. The valve assembly according to claim 3, wherein the valve element comprises:

a valve body comprising the second surface; and
a valve piston comprising:
a piston element comprising the first surface;
a slotted stem linking the piston element to the valve body; and
a pin attached to piston element and projecting radially away from the piston element,
and wherein the locking device comprises:
an upper latch body having a first profiled slot cooperating with the pin, said first slot comprising a main portion extending along an axial direction and a secondary portion extending in a direction transverse and radial to said axial direction; and
a latch retracting case coaxially displaceable with respect to the upper latch body and overlapping over the upper latch body, the latch retracting case having a second profiled slot cooperating with the pin, said second slot comprising a main portion extending along the axial direction and a secondary portion extending in a direction transverse to said axial direction, parallel to the transverse direction in which the secondary portion of the first slot extends, said latch retracting case cooperating with a latch locking mechanism of the inner tube member, such that the valve element is locked and the latch retracting case prevents the latch locking mechanism from engaging with latches of the core barrel head assembly upon displacement of the pin in the secondary portions of the first and second profiled slots.

6. A method for operating a valve assembly for use in a core barrel head assembly positionable within a drill string of a drilling apparatus driven by pressurized fluid, the valve assembly comprising:

a landing shoulder;
at least one upstream fluid flow port positionable within a fluid line of the drilling apparatus upstream of the landing shoulder;
at least one downstream fluid flow port positionable within the fluid line of the drilling apparatus downstream of the landing shoulder;
at least one fluid pressure communication port positionable within the fluid line of the drilling apparatus;
a movable valve element having a first side in fluid communication with pressurized fluid through the at least one pressure port and having a first surface that is influenced in the supply direction by a force FA from said fluid, and a second side facing in the opposite direction, in fluid communication with pressurized fluid through the at least one upstream fluid flow port and having a second surface that is influenced in the opposite direction by a force FB from said fluid;
at least one biasing element for opening the valve assembly by displacing the valve element from a closed position to an open position,
wherein the area of said second surface is greater than that of said first surface so that the force influencing the valve element in a closing direction, in the form of the force FB from the pressurized fluid acting on said second surface exceeds the force influencing the valve element in an opening direction, in a form of combining a force Fs from the biasing element and the force FA from the pressurized fluid acting on said first surface and wherein the at least one fluid pressure communication port and the at least one upstream fluid flow port form two sets of ports, the first set for fluid pressure communication with the movable valve element, and the second set for fluid flow required for drilling in which the fluid flow is blocked or opened by the movable valve element,
the method comprising:
supplying the pressurized fluid to the valve element in said closed position whereupon the valve assembly remains closed;
reducing the supply of pressurized fluid to the closed valve assembly; and
allowing a pressure force differential to decrease between said first and second sides, thereby enabling the biasing element to urge the valve element towards the open position, and thereby allowing fluid flow through the at least one upstream fluid flow port.

7. The method according to claim 6, wherein the valve assembly further comprises a locking device for mechanically locking the valve element in said closed position, wherein during supplying the pressurized fluid the valve element is in a mechanically locked closed position, the method further comprising:

causing the locking device to cease locking the valve element in the closed position after supplying the pressurized fluid and before reducing the supply of pressurized fluid.

8. The method according to claim 7, wherein the locking device comprises a pressure sleeve mechanically connected to a latch locking mechanism of the inner tube member and supplying pressurized fluid further comprises allowing fluid pressure to displace the pressure sleeve and engage a latch lock of the latch locking mechanism.

9. The method according to claim 7, wherein the valve element comprises:

a valve body comprising the second surface; and
a valve piston comprising: a piston element comprising the first surface; a slotted stem linking the piston element to the valve body; and a pin attached to piston element and projecting radially away from the piston element,
wherein the locking device comprises: an upper latch body having a first profiled slot cooperating with the pin, said first slot comprising a main portion extending along an axial direction and a secondary portion extending in a direction transverse and radial to said axial direction; and a latch retracting case coaxially displaceable with respect to the upper latch body and overlapping over the upper latch body, the latch retracting case having a second profiled slot cooperating with the pin, said second slot comprising a main portion extending along the axial direction and a secondary portion extending in a direction transverse to said axial direction, parallel to the transverse direction in which the secondary portion of the first slot extends, said latch retracting case cooperating with a latch locking mechanism of the inner tube member, such that the valve element is locked and the latch retracting case prevents the latch locking mechanism from engaging with latches of the core barrel head assembly upon displacement of the pin in the secondary portions of the first and second profiled slots,
and wherein supplying pressurized fluid further comprises displacing the pin from the secondary portions to the main portions of the first and second profiled slots, upon proper deployment of the latch locking mechanism, thereby allowing axial movement of the pin and valve piston.

10. A wire line core drill system, comprising:

a wire line core drill having an inner tube configured to collect core samples,
an outer tube connected to a drill bit, and
a valve assembly situated at the rear end of the inner tube, said valve assembly controlling the supply of a flushing medium in the form of a pressurized fluid, wherein the valve assembly comprises a landing shoulder, at least one upstream fluid flow port positionable within a fluid line of the drilling apparatus upstream of the landing shoulder, at least one downstream fluid flow port positionable within the fluid line of the drilling apparatus downstream of the landing shoulder, at least one fluid pressure communication port positionable within the fluid line of the drilling apparatus, a movable valve element having a first side in fluid communication with pressurized fluid through the at least one pressure communication port and having a first surface that is influenced in the supply direction by a force FA from said fluid, and a second side facing in the opposite direction, in fluid communication with pressurized fluid through the at least one upstream fluid flow port and having a second surface that is influenced in the opposite direction by a force FB from said fluid, and at least one biasing element for opening the valve assembly by displacing the valve element from a closed position to an open position, wherein the area of said second surface is greater than that of said first surface so that the force influencing the valve element in a closing direction, in the form of the force FB from the pressurized fluid acting on said second surface exceeds the force influencing the valve element in an opening direction, in a form of combining a force Fs from the biasing element and the force FA from the pressurized fluid actin on said first surface, whereby the valve element is retained in the closed position of the valve when pressurized fluid is supplied and wherein the at least one fluid pressure communication port and the at least one upstream fluid flow port form two sets of ports, the first set for fluid pressure communication with the movable valve element, and the second set for fluid flow required for drilling in which the fluid flow is blocked or opened by the movable valve element.
Patent History
Publication number: 20140353039
Type: Application
Filed: Jan 27, 2012
Publication Date: Dec 4, 2014
Applicant: ATLAS COPCO CANADA INC. (Dollard-des-Ormeaux,, QC)
Inventors: Paul Lambert (Chambly), Patrick Salvador (North Bay), Patrick Lu (North Bay)
Application Number: 14/375,081
Classifications
Current U.S. Class: Processes (175/57); With Means Movable Relative To Tool Or Shaft To Control Below-ground Passage (175/317)
International Classification: E21B 34/06 (20060101);