Patent Application
20220268118
N/A
The present invention is in the field of resource exploration core drilling systems leveraged to locate natural resources by creating retrievable cores of earth that may be accessed and checked for the presence of the desired resources in the field, pertaining particularly to an ergonomic shoe interface and method including apparatus for breaking the interface and restoring the interface in the field.
Within the field of earth exploration for natural resources scientists and prospectors often require physical core-samples to be extracted from the earth using core drilling equipment. Typical core drilling systems employ a rotating open-ended core bit rigidly joined to a pipe called a core barrel. In general practice, the rotating bit cuts a cylindrical elongated core sample of earth aided by downward penetration force through a drill string and fluid discharge. A stationary center core resulting from the drilling process may be retrieved by an inner pipe latched to a wire line, the pipe sliding down about the cylindrical core.
The far end of a core-capture inner pipe is referenced in the art as a shoe, typically an interface of two or more relatively heavy pipe components threaded together. The primary function of the shoe is to hold core breaking and retaining mechanisms. The lower shoe of the shoe interface being slightly larger in diameter than the upper shoe. The lower shoe hosting the core breaking apparatus and the upper shoe component of the interface hosting core holding or retaining apparatus referred to as basket catchers but not limited to basket catchers per se. Typically the lower shoe is fastened to an upper shoe by a threaded connection, which aids in assembly, and manufacturing time to machine seats, flanges, and mounts which hold and position basket-catchers, core breakers, and other core breaking/retaining mechanisms. However, some systems use a single shoe-body shoe, utilizing spacers or flanges to hold the core breakers, and potentially basket catchers and/or other core breaking or retaining mechanisms dependent on the type of earth formation being cored. For example, in loose sand, some systems may close completely around the core sample bottom after separation of the sample from the earth. In some embodiments, there could be a middle shoe or multiple middle shoe segments which also hold different core breaking or retention mechanisms.
The inside of the shoe interface may serve multiple functions including holding and positioning core breakers and holding basket catchers. The lower shoe on its outside may function as a pressure nozzle for fluid from a pump to both lubricate the core bit of the core barrel, and, in one embodiment help remove earth cuttings with hydraulic pressure. Hydraulic pressure which discharges within the core bit, and around the outside of the lower shoe assembly can act partially as the core cutting mechanism cutting core from the earth with hydraulic pressure. This may be somewhat dependent on the specific earth formation being core-drilled.
An adjustable lead screw mechanism facilitates the vertical distance between the lower shoe and the core bit for user control of the hydraulic pressure at the bit. The shoe interface has at least a lower shoe, but in practice typically contains two parts, generally the upper and lower shoe portions as described above. The upper shoe portion holds annular/radially aligned biased springs known in the art as basket catchers, the lower shoe portion typically holds and positions the movement of the core spring-breakers on their interior diameters. The lower shoe portion has an outside diameter larger than the upper shoe portion or the inner tube to help stabilize the inner tube pipe assembly. Middle shoes can be employed to hold other core breaking and retaining mechanisms, however, this is not typical. The shoe portions may be connected together to form the shoe interface (assembly). A step down function on the free end of the lower shoe component of the shoe assembly functions to focus pressurized fluid discharge.
The inner tube pipe is typically suspended on a bearing apparatus that hangs within the larger diameter core barrel. The core bit at the end of the core barrel typically includes an internal polygonal inside-diameter structure, the vertices thereof enabling fluid to pass around the shoe assembly to the core bit. The flats of the polygonal feature or other geometric form coupled with the larger inside diameter of the lower shoe function to keep the inner tube assembly from tilting or yawing. An inner tube assembly is retrieved with a core sample inside and is then laid horizontally such as on a workbench where a worker or workers proceed to disassemble the inner tube assembly to extract the captured core sample.
A challenge with this process is the difficulty relative to breaking the threaded interface that the shoe interface has with the inner tube pipe. During exploration drilling, many inner tube assemblies containing core samples up to three meters, or more, in length are retrieved and stacked for dis-assembly, core extraction, and reassembly. Six and nine meter length inner tube pipes, within the inner tube assembly are not unheard of. Typical workflow per bench line worker or pair of workers may be to extract 20 to 80 sample cores per day, with one worker typically threading and rethreading the shoe 40 to 160 times a day, sometimes under harsh on-site conditions such as extreme cold or hot weather, humidity, dirt, mud, and/or tar-saturated environments. Workers may endure 12 hour shifts consecutively for up to 26 days.
Typically core breakers are housed in the lower shoe due to their durability, and proximity to the bit, and thereby the lowest extent of a drilled center core. The core breakers are an open-sided conical spring steel piece with a smooth exterior and a barbed interior. As the drill string moves relatively upward, the core breakers slide down the tapered housing and contract to grip, and ultimately break the core from the earth. The purpose of the core breakers, and in general all core-retaining mechanisms, is to couple/lock the core to the shoe. Depending on the earth formation the core breakers may require significant force to break the core, and can become wedged and frictionally locked into the lower shoe. The unexpected, or unplanned for, result of utilizing core breakers to break the core from the earth, is that workers when disassembling the shoe must also break the friction connection between the core breakers and the lower shoe, or otherwise many times spin the shoe and the core, to remove the shoe. In some cases, the core weighs up to 100 pounds in rock formations. A worker on top of spinning off a fine threaded shoe may also be required to manually spin the core sample which is friction-locked to the core breakers, and thereby the shoe.
In addition to the challenges of increased friction for shoe-disassembly, the position of the workpiece and movements, including stance required by the bench workers in removing shoe assemblies from the inner pipes can be awkward for the worker and can cause strain or injury. Core drilling rigs generally use mobile workstations which are transported by helicopters, transfer trucks, or tracked vehicles, and therefore are confined to a small and quickly assembled workspace. The unintended consequence of designing confined work space is that the vice which holds the inner tube stationary may be positioned against a wall, on top of a bench, or against a railing, which may obstruct full rotation of a pipe wrench, additionally rig design is expensive and generally cannot be modified in the field. Once the thread lock is broken using a conventional pipe wrench, workers unthread the shoe assembly manually and may need to bend their wrists, or position their bodies in an awkward stance to manually unthread the shoe.
Many bench workers develop minor to severe carpal tunnel syndrome, tendonitis and crepitus, often interrupting sleep patterns, causing pain or discomfort requiring medication and eventually corrective surgery. As carpal tunnel syndromes, tendonitis, and crepitus are generally less visible negative safety outcomes on core drilling job-sites, and only appear after hundreds, or thousands or repetitions of moving a load, (generally with the wrist bearing the load) the extent of repetitive stress from removing a shoe interface from an inner tube pipe may not be obvious to safety managers, core drilling company owners, or rig tool design engineers.
Therefore, what is clearly needed is an ergonomically operable shoe interface for a core drilling system and an apparatus that facilitates ergonomic removal and replacement of the interface or assembly in a production line.
According to an embodiment of the present invention, a shoe assembly of an earth core drilling system is provided and includes a lower annular shoe component threaded onto an upper annular shoe component, the shoe assembly may be removably threaded on to an annular inner tube pipe integral to the earth core drilling system, the lower tubular body having a torque pattern of two or more surface indentations or slots disposed strategically about the outer periphery thereof, the torque pattern matching a pattern of protrusive elements on a friction-breaking socket tool. In this embodiment a worker may place the friction-breaking socket tool on or over the lower tubular body and use that tool to break the threaded interface between the upper shoe component and the inner tube pipe of the core drilling system and unscrew the shoe assembly from the inner tube pipe to remove an earth core sample from the inner tube pipe and to screw the shoe assembly back on to the inner tube pipe.
In one embodiment, the two or more surface indentations comprising the torque pattern are elongated slots parallel to one another, and aligned with the longitudinal axis of the lower tubular body, and wherein the friction-breaking tool is a socket tool with a handle and the matching protrusions are elongated keys that fit into the slots from the free end of the lower tubular body. In another embodiment, the surface indentations are blind seats linear in orientation, the torque pattern disposed orthogonally to the longitudinal axis of the lower tubular body around the periphery thereof, and wherein the friction-breaking tool is a crescent tool having matching protrusions on the inside of a crescent head, with the crescent head having a handle.
In a variation of the above slot embodiment, the torque pattern includes five slots in a star pattern, accepting a matching star pattern of five elongated keys arrayed about the inside of the socket tool. In a further variation of the embodiment, the socket tool handle is a breaker bar handle. In yet another variation of the embodiment specifying slots as the torque pattern, the socket tool handle is a ratchet handle.
In one embodiment of the present invention, the friction-breaking tool is a socket tool operated by a pneumatic system, an electric drive system, or a hydraulic drive system. In another variation of the embodiment specifying slot as the torque pattern, the slots extend at least partially on to the peripheral surface of the upper shoe component, the threaded interface designed to align the slot patterns when the components are fully threaded together.
In various embodiments described in enabling detail herein, the inventor provides a unique system for removing and replacing the shoe assembly attached to an inner pipe of an earth core drilling apparatus. An object of the invention is to reduce the manual labor currently required to remove and replace the shoe assembly, thereby reducing the potential for injury to production bench workers performing the operation. The present invention is described using the following examples, which may describe more than one relevant embodiment falling within the scope of the invention.
Inner tube assembly 102 includes all of the components needed to slide down around a stationary core, and in conjunction with an upward relative force provided by the drilling rig to separate a measured section of that core, and retain the separated core sample section within the inner tube assembly. The inner tube assembly 102 can then be retrieved by wire line, using latch 115 for example, and an empty inner tube assembly 102 may then be attached to the drill equipment wire line and lowered back down into core barrel 101 to capture a next sample. The inner tube assembly 102 may include a latching head section 115 at the top interfacing with drill equipment suspending apparatus. Inner tube assembly 102 may include a bearing 105 connected to a lead-screw mechanism 114 on top, and to an inner tube pipe section 106. Lead-screw mechanism 114 may hold a landing-nut 109 which, after lowering the inner tube assembly into the core barrel, is suspended by the core barrel landing ring 116.
Inner tube pipe 106 may include a check valve 107, which may be a ball check valve. Inner tube assembly may further include a plastic pipe lining pipe 108 adapted with an outside diameter just smaller than the inside diameter of the inner tube pipe 106. The inside diameter of lining pipe 108 is just large enough to slide over a stationary core without excessive play. The inner tube assembly may further include a plastic pipe lining pipe 108 adapted with an outside diameter just smaller than the inside diameter of the inner tube pipe 106. Liner pipe 108 slides up into inner tube pipe 106.
Inner tube assembly 102 includes a lower shoe 112 in the shoe assembly, the lower shoe 112 hosting a core breaking apparatus 113 (not visible). Lower tubular body 112 may be somewhat larger in outside diameter than the upper shoe component 111. Outside diameters of shoe components 112 (lower shoe) and 111 (upper shoe) may vary according to a desired core diameter, which may range from one and one-half inches to several inches in diameter depending on system and operation. A shoe assembly containing an upper shoe component 111 with a basket catcher apparatus 110 is adapted to be installed (threaded) onto the lower end of inner tube pipe 106. Basket catcher 110 seats within the inside diameter of upper shoe component 111 and functions to retain hold of a separated core sample.
When assembled, the only visible parts of the inner pipe assembly 102 are lower shoe component 112, upper shoe component 111, inner tube pipe 106, rig-latching head 104, lead-screw mechanism 114, landing nut 109, bearing assembly 105, and the bearing crossover assembly 118. In the operation of extracting core samples, connection between the upper shoe component 111 and the inner tube pipe 106 must be loosed and the shoe threaded off from the inner tube pipe 106. Inner tube pipe 106 has external threads that match a female thread pattern on the inside top end of upper shoe component 111. To extract a core sample, the whole shoe assembly must be removed from the inner pipe assembly 102 and replaced once the core sample is removed from the inner pipe assembly.
Referring now to
The annular form of the shoe interface acts in conjunction with hydraulic fluid and the bearing assembly described in
Additionally, in many core drilled formations the pressurized hydraulic fluid discharging around the annular form of the lower shoe assembly may play an important role in cutting a cylindrical core from the earth and in cleaning the bit of certain types of core build ups. In particular if the inner tube assembly 102 tilts or yaws relative to the core barrel, core may jam and thereby plug the inner tube orifice prior to the end of the core drilling cut. Inner tube assembly yaw and tilt may also cause the inner tube assembly to be sheared into an ovular form, which can potentially cause core slippage during wireline retrieval.
In the current art, a pipe wrench which grips on only two surfaces of the shoe assembly creates an increased risk of marring or ovalling of the shoe. On the outside diameter the shoe must remain annular due to the tolerances with the rotating polygonal inside diameter shape of the core bit, and also for even distribution of discharging hydraulic fluid. Discharging hydraulic fluid plays a crucial role within the lubrication of core entering into the inner tube assembly, cleaning the bit, and in some earth formations cutting the core with hydraulic pressure. Core drillers may set and change the distance between the lower shoe and core bit using the lead screw mechanism 114 and landing nut 109 depending on which earth formation they are within, as fluid discharge pressure is a key parameter of core successful core drilling. Providing flats for fitting a wrench on lower tubular body 112 similar to flats 208 on upper shoe component 111 may be detrimental to the shoe assembly due to the possibility of yaw, and uneven fluid discharge.
A consequence of utilizing tool steel dies to grip the shoe interface is that a relatively softer material, perhaps 4140 molybdenum alloy steel may be used for the shoes' bodies, which decreases the lifespan of the shoe assembly itself relative to harder materials; the threads wearing faster, and the annular form becoming marred, or distorted quicker. The use of tool steel dies to grip the shoe relatively decreases the lifespan of the shoe's annular form, as the dies require slight deformation of the surface of the shoe to grip it. Alternatively keys 504 (of Fig.5) may use relatively softer material, such as brass, aluminum or copper to transfer torque to slots 203 (of
Referring now back to
A plurality of elongated slots 203 are machined longitudinally along the outside surface of lower tubular body 112 to form a torque pattern of slots for securely seating a torque busting tool (not illustrated here) that may be attached to or otherwise fitted over the outside surface of lower tubular body 112. Such a tool may include a leverage handle or pneumatic power interface that can be used in place of a gripping pipe wrench to break the thread lock so unscrewing the shoe assembly from the end of the inner pipe is possible without tool slippage that may mar the outside surface of the pipe material. Electric and hydraulically powered socket tools may be used instead of a pneumatic tool without departing from the spirit and scope of the present invention.
In one embodiment, there may be two elongated parallel slots 203 provided on opposite sides of lower tubular body 112. In other embodiments, an equally spaced array of parallel slots 203 may present a three-slot pattern, a four-slot pattern, a star pattern (five slots) and so on. In alternative embodiments, slots 203 may be spaced unequally without departing from the spirit and scope of the invention. In this embodiment, slots 203 break out of both ends of the thicker wall of material comprising the center portion of lower tubular body 112. That is not required in order to practice the invention as long as the slot pattern 203 breaks out to the free end of the pipe allowing a tool like a deep socket with a key pattern that matches the slot pattern to be placed over the lower tubular body 112 from the free end wherein the key pattern engages the slot pattern 203. In this embodiment, slots 203 break out of both ends of the thicker wall of material comprising the center portion of lower shoe. That is not required in order to practice the invention as long as the slot pattern breaks out to the free end of the pipe allowing a tool like a deep socket with a key pattern that matches the slot pattern to be placed over the lower shoe from the free end wherein the key pattern engages the slot pattern. In an alternative embodiment, the lower tubular body does not include a step-down feature like feature 204. In still another embodiment, the larger diameter pipe of the lower shoe and slots extend to the upper shoe, the threads machined to enable the slots of the upper shoe component 111 and the lower tubular body 112 to align.
In yet another embodiment only a lower shoe is used, in such an embodiment if basket catchers (110 of
Referring now to
Step down surface 204 is preferably concentric with the outside diameter of lower tubular body 112. Wall 201 depicts the stepped down wall marking the ends of slots 203. In one embodiment, a socket device may be fabricated with a matching key pattern that may be slipped onto the free end of lower shoe component 112 far enough along the longitudinal axis of the pipe material to engage the key pattern into the slot pattern. A socket device may be fashioned to fit a breaker bar or sturdy ratchet handle functioning as a lever that may be operated to loosen the interface between the shoe assembly and the inner tube pipe. The internal diameter of lower shoe component 112 has a conical taper in the wall thickness 301 to provide a seat for a core breaker apparatus (not illustrated).
Elongated keys 504 are square keys in this embodiment that have a width dimension just smaller than the inside diameter of the slots. Socket 501 may be modified at the back wall with a center opening that may fit a square key of a breaker bar handle 502. In addition to a square key, any geometric pattern may be used to couple a socket tool to a breaker bar. In this case a breaker bar (not pictured) may be leveraged by handle 502 to break the thread lock keeping the shoe assembly and inner pipe 106 tightly threaded together before the shoe assembly remaining fictionally joined may be removed from the inner tube pipe 106.
In one embodiment, the breaking tool is a ratchet tool having a bi-directional ratchet disc 503, a drive square 505, and a handle 502 allowing the socket tool 501 to be used entirely for screwing the shoe assembly on to the inner tube pipe. In one embodiment, the ratchet tool may be a pneumatic tool that uses compressed air to spin the socket in the two directions saving workers from manual threading operations which may be difficult with fine pipe threads that tend to become sticky or otherwise friction tight and resist movement, or may be friction locked to the part or all of the 3m core sample by the result of drilling practice and core breakers.
A bench worker may place socket tool 501 over the free end of lower tubular body 112 from
After the thread lock is overcome, rotation of the shoe assembly may need to overcome friction related to the core retention mechanisms and their friction lock to the core. A typical embodiment of the invention uses a high torque mode, for example a breaker bar which leverages a manually produced force to break the initial thread lock. After the high torque mode of the tool overcomes the initial high friction resistance to rotation, typically the tool will use a high speed method of rotation, for example a pneumatic, electric, or hydraulic drive which spins a socket tool. An additional method of high speed rotation is to use a 90 degree handle attached to the breaker bar, offset and parallel to the longitudinal axis of the inner tube assembly which acts as a crank handle to spin the socket, and shoe interface. Within the method of using a manual hand crank for high speed rotation, a segment of the breaker bar can pivot 90 degrees to turn into a crank handle. The shoe assembly contains all of the components which host core retention mechanisms, typically an upper and lower shoe, core breakers (113), and basket-catchers (110). To break the friction lock of the shoe assembly the shoe assembly must rotate relative to the inner tube pipe.
After the core sample is secured, the shoe assembly must be threaded back onto the inner tube pipe. The same tool may be used to re-thread the shoe interface to the inner tube pipe, and then tighten the thread interface with sufficient force to establish the friction-lock bottoming of the threads. To re-fasten the shoe interface typically the shoe assembly spins relative to a stationary inner tube pipe. Sand dirt and tar can contaminate the threads 207, and 209 (referring to
In another embodiment of the present invention, automation may be used to remove the shoe assembly after the friction lock of the threaded interface is broken using the socket tool 501 and breaker handle 502. In one embodiment, in place of elongated slots, blind seats may be placed around the perimeter the lower tubular body, upper shoe component or any place on the shoe assembly wherein a breaker tool with a crescent head having matching protrusions may be placed orthogonally over the shoe assembly, provided that the seats are sufficiently far enough away from the free end of lower tubular body 112 to not impede stabilization, and fluid discharge. For example, an aircraft automation wrench tool that is essentially two motors that spins an open ended C-wrench.
In this embodiment, a worker may place the tool over the pipe engaging the blind orthogonal seats (208) and then use a leveraged small amount of force to break the friction lock. Within embodiments using crescent heads which fit onto orthogonal blind seats (208), an off axis pneumatic, electric or hydraulic gear system can be utilized to spin the crescent head and thereby spin the shoe in two directions, relieving the worker of manually threading.
Occasionally core sticks out of the lower shoe a few inches, in such cases a worker may break the core off using a hammer to allow a deep socket tool with a key pattern to reach slot pattern 203, or use a deeper reach socket. However, in a variation of an embodiment which works around the occasionally problem of core sticking out of the inner tube assembly mechanically, an open ended socket tool which slips over the core-sample, utilizes a handle which acts as a breaker bar. In a variation of this embodiment the breaker bar may contain a motor or an off axis power transmission, generally a ring gear, or pulley system which is powered by pneumatics, hydraulics, which spins the open ended key-pattern from its side. In another embodiment of the present invention, automation may be used to remove shoe assembly from the inner tube pipe. In that embodiment, a machine may place the socket tool over the shoe engaging the seats, or slots and may produce a leveraged force to break the friction lock. A pneumatic, electric, or hydraulic driven socket tool allows automation to perform all of the threading operations relieving the bench worker of threading by hand and therefore protecting the worker from potential injury over time.
It will be apparent with skill in the art that the torque pattern and matching tool of the present invention may be provided using some or all the elements described herein. The arrangement of elements and functionality thereof relative to the invention is described in different embodiments each of which is an implementation of the present invention. While the uses and methods are described in enabling detail herein, it is to be noted that many alterations could be made in the details of the construction and the arrangement of the elements without departing from the spirit and scope of this invention. The present invention is limited only by the breadth of the claims below.
