Abstract: The upper head assembly includes a main body, a retractable body, a support element and a rear element. A fluid control means is provided for increasing the passage of fluid during the descent into the well are disposed on the main body and comprise a closure/opening body that selectively permits fluid to pass through a bypass chamber inside the main body, in a working position, or through an area of rapid descent that facilitates the passage by following a path, during descent. The fluid bypass chamber is formed by a central chamber with inlet ports and outlet ports that allow a connection of fluid between the central chamber and the outside of the main body. The closure/opening body blocks the flow through the area of rapid descent when the working position is reached.

Abstract: An inner tube head assembly for a core barrel assembly having a latch casing coupled to a latch body, a landing shoulder coupled to the latch body and a spindle, and an inner tube cap assembly coupled between the spindle and an inner tube cap adapter. The landing shoulder and the inner tube cap adapter are a first size. The latch casing, the latch body, the spindle, and the inner tube cap assembly are a second size. The inner tube head assembly includes latches configured to work with the inner tube head assembly of the first size and the drill string of the second size. The first size is larger than the second size. The inner tube head assembly engages a drill string sized to cooperate with the first size. A core drilling system is also described.

Abstract: A drilling fluid channel structure of a core drilling rig includes a fluid channel activation module, a pressure relief module, a flow diverging and blocking module, a driving fluid channel and a cooling fluid channel. The fluid channel activation module, the pressure relief module and the flow diverging and blocking module are connected sequentially from the rear to the front. The driving fluid channel and the cooling fluid channel are connected at the rear side thereof to the flow diverging and blocking module. The driving fluid channel includes a driving section located between a stator and a rotor of a driving motor. The driving fluid channel is provided with a driving fluid outlet at the front side of the driving section. The cooling fluid channel passes through a layer disposed between an integrity-preserving compartment and an outer barrel.

Abstract: [Problem] To provide: a core barrel head capable of definitely recovering an inner tube in which a geological sample has been collected in a situation where excavation is performed in a horizontal direction and in a rising gradient direction; an inner tube assembly provided with said core barrel head; and an inner tube recovery method.

Abstract: A core detection device of a coring instrument includes a base body and a core switch mechanism provided on the base body. The base body is provided with a core channel communicated with a core barrel. The core switch mechanism includes a detection portion, a connecting rod assembly and a travel switch which are sequentially arranged and connected along a length direction of the coring instrument. The detection portion is rotatably installed on the base body and one end thereof is extended into the core channel, so that a core passing through the core channel pushes the detection portion to rotate. The connecting rod assembly can be pulled by the rotating detection portion to trigger the travel switch to operate. The core switch mechanism adopts a slider-connecting rod structure, and the kinematic pairs are mainly a sliding pair and a rotating pair.

Abstract: A downhole device delivery and drive transfer system includes a sub which is arranged to attach to a drill string and a tool which is configured to enable it to travel through the drill string and releasably couple to the sub. The sub and the tool are arranged so that when they are releasably coupled to each other torque imparted to the drill string is transferred by the sub to the tool. The tool is arranged to carry one or more devices for performing one or more downhole functions such as core drilling, hole reaming or wedge placement for directional drilling. The system also has a guide mechanism that operates between the sub and the tool to guide the tool to a known rotational orientation relative to the sub as the tool travels into the sub. A fluid control system controls the flow of fluid through the tool through a downhole outlet and a plurality of ports intermediate opposite ends of the tool.

Abstract: A device for transport of an apparatus along a conduit or bore hole including a drill string. The device has a body having a coupled upper body portion and a lower body portion movable axially relative to each other. A fluid flow path in the body selectively enables fluid to flow through the body. A first valve system at a first end of the internal fluid flow path 58 is operable by a pressure differential between a region external of the body and the fluid flow path. A second valve system at a second end of the internal fluid flow path is operable by relative movement between the upper body portion and lower body portion. The body has one or more openings downstream of the first valve system through which fluid can flow or fluid pressure can be communicated to the apparatus.

Abstract: A wire-line core drilling tool includes an outer barrel assembly and an inner barrel assembly. The inner barrel assembly is provided with an elastic clamp positioning mechanism, an in-place reporting and core blockage alarm mechanism, a single-action mechanism, a core barrel check valve mechanism, a core barrel and a core-breaking mechanism. The elastic clamp positioning mechanism adopts a multi-point hinged mode. The in-place reporting and core blockage alarm mechanism is integrally formed. The single-action mechanism adopts a cooperating structure of an upper polycrystalline diamond compact (PDC) bearing, a lower PDC bearing and a tungsten carbide (TC) bearing arranged in the middle. The outer barrel assembly is provided with an elastic clamp retaining head, an elastic clamp chamber, an upper reamer, an outer barrel, a lower reamer and a drill bit. A ring base is arranged, and a centralizing ring is arranged.

Abstract: The present application discloses the use of the pre-stressed steel strand in, the procedure of multi-angle core drilling. Using the properties of high strength and toughness of pre-stressed steel strand material, the core internal pipe is pushed inside the drill rod without deformation and damage. The rolling wheel is designed to rapidly take out and put back the pre-stressed steel strand to finish the extracting of the core, without taking out and putting back the drill rod. Without altering the original structure of the drilling machine, the technology of 360° core drilling is realized. Problems of tedious and arduous operations and a low efficiency in multi-angle drilling are resolved completely. The use of the pre-stressed steel strand not only can significantly improve the drilling-in efficiency, but also is beneficial to guarantee the quality of the rock mineral coring, reduce the cost of drilling, lower the labor intensity notably.

Abstract: Implementations of the present invention include a core barrel assembly including external fluid pathways extending generally axially long the outer surface of the core barrel assembly. The one or more external fluid pathways can allow for increased fluid flow around a latch mechanism. The increased fluid flow around the latch mechanism can allow the core barrel assembly to travel faster within the drill string, can allow drilling fluid to pass by the latch mechanism when engaged. Implementations of the present invention also include drilling systems including external fluid pathways, and methods of retrieving a core sample using such drilling systems.

Abstract: A bushing for positioning within a core barrel assembly during an up-hole drilling operation. The bushing has a wall with an inner surface and an outer surface. The inner surface defines an inlet, an outlet, and a central bore of the bushing. The central bore surrounds a longitudinal axis of the bushing and extends between the inlet and the outlet. The outer surface has a first portion positioned proximate the inlet and a second portion positioned proximate the outlet. The first portion of the outer surface of the wall projects outwardly from the second portion of the outer surface relative to the longitudinal axis of the bushing such that the first portion of the outer surface defines opposed first and second shoulder surfaces extending substantially perpendicularly relative to the longitudinal axis. Core barrel head assemblies including such bushings are also described.

Abstract: Implementations include a core barrel assembly having a driven latch mechanism. The driven latch mechanism can lock the core barrel assembly axially and rotationally relative to a drill string. The driven latch mechanism can include a plurality of wedge members positioned on a plurality of driving surfaces. Rotation of the drill string can cause the plurality of wedge members to wedge between an inner diameter of the drill string and the plurality of driving surfaces, thereby rotationally locking the core barrel assembly relative to the drill string. Implementations of the present invention also include drilling systems including such driven latch mechanisms, and methods of retrieving a core sample using such drilling systems.

Abstract: A latch assembly for a diamond core drill wire line. Included is a cylindrical main body having a main body interior, an outer wall, a main body end and a latch end. A ball hole is defined through the main body. An inner shaft ball lock is contained within the main body. A spring is disposed on the inner shaft ball lock. A main body top is attached to the main body end to contain the inner shaft ball lock within the main body and limit upstream movement of the inner shaft ball lock. A steel ball is then captured between the inner shaft ball lock and the outer wall of the main body such that upon axial movement of the inner shaft ball lock the ball penetrates up through the outer wall to extend past the main body to thereby latch onto an outer tube assembly.

Abstract: An assembly may be disposed within a drill string. The assembly may be moved within and along the drill string using hydraulic pressure. A core sample may be collected within the assembly, and the assembly may be retrieved to obtain the core sample. The assembly may include a seal that may be configured to form a seal with different inner diameters of a variable-diameter drill rod of the drill string.

Abstract: A core lifter may be used in a drilling system. An exterior surface of the core lifter may include a plurality of longitudinally-oriented recesses. The core lifter may include a raised contact feature that may extend inwardly away from a gripping surface of the core lifter. The core lifter may include a flared skirt configured to limit movement of the core lifter relative to a core lifter case. The core lifter may be formed via stamping a sheet of material.

Abstract: Drilling systems and methods for deploying a latch mechanism upon reaching a drilling position. The drilling systems and methods permit spinning of a drill string to cause a core barrel head assembly to spin through the frictional mating of a landing shoulder of the head assembly and a landing ring of an outer tube assembly. The spinning of the drill string induces a centrifugal and/or radial force that acts on the latch mechanism to overcome the frictional retention forces acting on the latch mechanism, thereby permitting deployment of the latch mechanism.

Abstract: A locking mechanism for locking an insertable device relative to an outer tube of a ground drill comprises at least one latch, which is arranged to releasably retain the insertable device in a substantially fixed axial position relative to the outer tube. The locking mechanism comprises a cam and a cam follower, which are arranged to control a radial position of the latch. The locking system may be used in a ground drill system.

Abstract: A head assembly includes a body, a spearhead operatively associated with the body and configured to translate axially relative to the body, and at least one latch operatively associated with the spearhead and the body. The latch is configured to move between an extended position and a retracted position relative to the body in response to axial translation of the spearhead relative to the body. In an extended position, the latch covers more than 25% of the circumference of the body adjacent the latches.

Abstract: A bushing for positioning within a core barrel assembly during an up-hole drilling operation.

Abstract: Implementations of the present invention include a core barrel assembly having a driven latch mechanism. The driven latch mechanism can lock the core barrel assembly axially and rotationally relative to a drill string. The driven latch mechanism can include a plurality of wedge members positioned on a plurality of driving surfaces. Rotation of the drill string can cause the plurality of wedge members to wedge between an inner diameter of the drill string and the plurality of driving surfaces, thereby rotationally locking the core barrel assembly relative to the drill string. The driven latch mechanism can further include a refracted groove adapted to lock the plurality of wedge members radially within the core barrel assembly, thereby allowing for faster travel within the drill string. Implementations of the present invention also include drilling systems including such driven latch mechanisms, and methods of retrieving a core sample using such drilling systems.

Abstract: High productivity core drilling systems include a drill string, an inner core barrel assembly, an outer core barrel assembly, and a retrieval tool that connects the inner core barrel assembly to a wireline cable and hoist. The drill string comprises multiple variable geometry drill rods. The inner core barrel assembly comprises a non-dragging latching mechanism, such as a fluid-driven latching mechanism that contains a detect mechanism that retains the latches in either an engaged or a retracted position. The inner core barrel assembly also comprised high efficiency fluid porting.

Abstract: A core catcher includes a housing having an inner wall that defines an axial bore through the housing. A retention member is disposed within the housing and is coupled to a first hinge tab that defines a first hinge barrel with the inner wall of the housing. A first closure member has a slot that is engaged with the first hinge tab and a pivot edge that is at least partially disposed within the first hinge barrel. In an open position, the first closure member is disposed in an annulus between a sleeve that is slidably disposed within the housing and the housing. In a closed position the first closure member is disposed at least partially across the axial bore of the housing.

Abstract: A head assembly includes a body, a spearhead operatively associated with the body and configured to translate axially relative to the body, and at least one latch operatively associated with the spearhead and the body. The latch is configured to move between an extended position and a retracted position relative to the body in response to axial translation of the spearhead relative to the body. In an extended position, the latch covers more than 25% of the circumference of the body adjacent the latches.

Abstract: A core barrel assembly for retrieving a core sample. The core barrel assembly includes a retrieving element defining an inner tube for retrieving the core sample thereinto, a locking assembly including latch dogs for locking the core retrieving assembly inside the outer tube and a valve assembly mechanically coupled to the locking assembly and provided proximally relative thereto for controlling the flow of fluid across the core barrel assembly. The core barrel assembly is operable in a retrieving configuration in which the latch dogs are retracted and the valve assembly is closed, in a locking configuration in which a locking element locks the latch dogs in an extended configuration and the valve assembly is open and a retrieving configuration, in which the latch dogs are force in a retracted configuration and the valve assembly is open.

Abstract: High productivity core drilling systems include a drill string, an inner core barrel assembly, an outer core barrel assembly, and a retrieval tool that connects the inner core barrel assembly to a wireline cable and hoist. The drill string comprises multiple variable geometry drill rods. The inner core barrel assembly comprises a non-dragging latching mechanism, such as a fluid-driven latching mechanism that contains a detent mechanism that retains the latches in either an engaged or a retracted position. The inner core barrel assembly also comprised high efficiency fluid porting.

Abstract: A retrieval system for a wireline drilling system having a winch, a wireline rope connected to the winch, and a core sampler connected to the wireline rope. The retrieval system includes a radio-frequency identification (RFID) transponder and a controller that, in response to receiving a wireless signal from the RFID transponder, automatically adjusts a speed at which the winch retrieves the core sampler.

Abstract: A latch head assembly for a core receiving apparatus including a core tube assembly and a retrieving head is provided. The latch head assembly includes a support, a first coupling for releasably engaging the retrieving device coupled to a first end of the support, and a second coupling for releasably engaging the core tube assembly coupled to a second end of the support. A core receiving apparatus including the latch head assembly is also provided. A method for inserting and retrieving the core receiving apparatus into and from a drill string is also provided.

Abstract: A head assembly includes a body, a spearhead operatively associated with the body and configured to translate axially relative to the body, and at least one latch operatively associated with the spearhead and the body. The latch is configured to move between an extended position and a retracted position relative to the body in response to axial translation of the spearhead relative to the body. In an extended position, the latch covers more than 25% of the circumference of the body adjacent the latches.

Abstract: A method in core drilling, wherein a tubular drill bit (8) being arranged at the end of a tubular drill string (6) is driven under rotation against a material intended for drilling, and wherein for the purpose of core retrieving, a tool (17, 20) is brought inside the drill string to an operative position in the area of the drill bit. Acoustic vibrations (24, 25) from the drill string are sensed when the tool is brought to its operative position, sensed acoustic vibrations are analysed for detecting the occurrence of acoustic vibrations characteristic for when the tool has reached its operative position, and an output signal is emitted when the occurrence of vibrations characteristic of when the tool has reached its operative position has been detected. The invention also concerns a device and a drill rig.

Abstract: A braking device for drilling operations in a borehole includes a brake retainer having a plurality of brake connector openings defined therein, a body member having a tapered surface having a first diameter and a second diameter, the second diameter being larger than the first diameter, at least one brake element positioned at least partially between the brake retainer and the body member and in communication with the tapered surface and at least one of the brake connector openings, and a bias member configured to exert a biasing force on the body member to move the body member toward the brake retainer to move the brake element from contact with the first diameter of the tapered surface toward contact with the second diameter.

Abstract: A drill bit is disclosed. The drill bit has an axis, and a barrel, and a cutting member fixed to the barrel. The barrel is arranged to engage a drill shaft for driving the drill bit around the axis. The barrel and the cutting member are adjacently located on the axis. The drill bit has an aperture centered on the axis, the aperture passing completely through both the cutting member and barrel.

Abstract: A core lifter may be used in a drilling system. An exterior surface of the core lifter may include a plurality of longitudinally-oriented recesses. The core lifter may include a raised contact feature that may extend inwardly away from a gripping surface of the core lifter. The core lifter may include a flared skirt configured to limit movement of the core lifter relative to a core lifter case. The core lifter may be formed via stamping a sheet of material.

Abstract: High productivity core drilling systems are described. The system includes a drill string, an inner core barrel assembly, an outer core barrel assembly, and a retrieval tool that connects the inner core barrel assembly to a wireline cable and hoist. The drill string comprises multiple variable geometry drill rods. The inner core barrel assembly comprises a non-dragging latching mechanism, such as a fluid-driven latching mechanism that contains a detent mechanism that retains the latches in either an engaged or a retracted position. The inner core barrel assembly also comprised high efficiency fluid porting. Accordingly, the drilling system significantly increases productivity and efficiency in core drilling operations by reducing the time required for the inner core barrel assembly to travel through the drill string. Other embodiments are also described.

Abstract: A jointed spearhead assembly can include a base portion that is adapted to be connected to a down-hole object and a spearhead portion having a first end and a second. The second end includes a follower tab with a non-convex first follower interface. The spearhead portion can be pivotally coupled to the base portion.

Abstract: A head assembly includes a body, a spearhead operatively associated with the body and configured to translate axially relative to the body, and at least one latch operatively associated with the spearhead and the body. The latch is configured to move between an extended position and a retracted position relative to the body in response to axial translation of the spearhead relative to the body. In an extended position, the latch covers more than 25% of the circumference of the body adjacent the latches.

Abstract: A latch head assembly for a core receiving apparatus including a core tube assembly and a retrieving head is provided. The latch head assembly includes a support, a first coupling for releasably engaging the retrieving device coupled to a first end of the support, and a second coupling for releasably engaging the core tube assembly coupled to a second end of the support. A core receiving apparatus including the latch head assembly is also provided. A method for inserting and retrieving the core receiving apparatus into and from a drill string is also provided.

Abstract: A coring bit, including an outer hollow coring shaft, and a rotationally uncoupled internal sleeve disposed inside the outer hollow coring shaft. The rotationally uncoupled internal sleeve may be a non-rotating internal sleeve. The rotationally uncoupled internal sleeve may be a free-floating internal sleeve.

Abstract: A spearhead assembly (10) comprises a base (12) provided with a slot (14) at one end (16) which opens onto an outer surface (13) of the base (12). The outer surface (13) is composed of three contiguous surface portions (18, 20 and 22). A spearpoint (20) is pivotally coupled at its proximal end (26), which is disposed in the slot (14), to the base (12). A distal end (28) of the spearpoint (24) extends or projects beyond the slot (14) and the surface (13) of the base (12). A spearpoint positioning system (30) urges the spearpoint (24) toward one of three annually spaced positioned. These positions are characterised by the spearpoint (24) extending substantially perpendicular to parallel opposed edges of the slot (14) which open onto, or are flanked by, the surface portions (18), (20 and 22). Moving the spearpoint from one position to another requires the application of an external force.

Abstract: Inner core barrel head assembly (10) includes an upper latch body (24), a plurality of latching balls (26) which are retained in the latch body (24) and a locking sleeve (28) disposed within the latch body (24). The sleeve (28) has an outer circumferential latching surface (30) of a first outer diameter and an outer circumferential release surface (32) of a second outer diameter smaller than the first outer diameter. The locking sleeve is axially moveable relative to the upper latch body (24) between a latching position and a release position. In the latching position, the latching surface (30) is in radial alignment with the balls (26), forcing the balls (26) radially outwardly into a latch seat (12) provided on a core barrel (20) attached to a lower end of a drill rod (14). This latches the assembly (10) to the core barrel preventing withdrawal.

Abstract: A method and apparatus for downhole coring while receiving logging-while-drilling tool data. The apparatus includes core collar and a retrievable core barrel. The retrievable core barrel receives core from a borehole which is sent to the surface for analysis via wireline and latching tool The core collar includes logging-while-drilling tools for the simultaneous measurement of formation properties during the core excavation process. Examples of logging-while-drilling tools include nuclear sensors, resistivity sensors, gamma ray sensors, and bit resistivity sensors. The disclosed method allows for precise core-log depth calibration and core orientation within a single borehole, and without at pipe trip, providing both time saving and unique scientific advantages.

Abstract: A method and apparatus for downhole coring while receiving logging-while-drilling tool data. The apparatus includes core collar and a retrievable core barrel. The retrievable core barrel receives core from a borehole which is sent to the surface for analysis via wireline and latching tool The core collar includes logging-while-drilling tools for the simultaneous measurement of formation properties during the core excavation process. Examples of logging-while-drilling tools include nuclear sensors, resistivity sensors, gamma ray sensors, and bit resistivity sensors. The disclosed method allows for precise core-log depth calibration and core orientation within a single borehole, and without at pipe trip, providing both time saving and unique scientific advantages.

Abstract: A bit retention apparatus for the use of retrieving the hammer bit in cases of shankage. The apparatus incorporates a dual sleeve design that fits over the chuck and the extended head section of the hammer bit. The first, “inner” sleeve has two or more ring pieces that fit onto the chuck and have the retention ring fitted into the lower section of the sleeve. The second, “outer” sleeve fits onto the chuck over the inner sleeve to provide protect to the inner sleeve while pulling the shanked bit out of the well bore. Attachment to the bit is accomplished by collars, knobs, or threads on the interior of the sleeves that correspond with holding bands, retention rings, or threads on the bit and chuck.

Abstract: Disclosed herein are a crustal core sampler, by which a crustal core sample can be cored in a state coated with a flow-able coating material free of any contamination, and a method of coring a core sample using this crustal core sampler. The crustal core sampler comprises a drilling mechanism and a barrel, wherein the barrel is equipped with a flow-able coating material-ejecting mechanism, and a columnar crustal core portion is coated with a flow-able coating material. Alternatively, the crustal core sampler is constructed by a drill pipe and an inner barrel, wherein the inner barrel is equipped with an inner barrel body, a core elevator, a channel-forming member for forming a flow-able coating material-running channel and flow-able coating material-ejecting openings, and a columnar crustal core portion is coated with a flow-able coating material.

Abstract: The present invention relates to a locking device (4) for a wire line core drilling system comprising an inner tube (2) by means of which core samples are collected, and an outer tube (1) connected to a drill bit, which locking device is applied in the rear end of the inner tube. The locking device (4) comprises locking members (7, 9) so designed that, when the inner tube has been inserted into the outer tube and has assumed the correct position inside the outer tube for drilling, in one and the same movement it simultaneously effects mechanical locking of the inner tube (2) in relation to the outer tube (1) and release of a gripping means (10; 25) of an accompanying device (5; 26) connected to the inner tube.

Abstract: Inner core barrel head assembly (10) includes an upper latch body (24), a plurality of latching balls (26) which are retained in the latch body (24) and a locking sleeve (28) disposed within the latch body (24). The sleeve (28) has an outer circumferential latching surface (30) of a first outer diameter and an outer circumferential release surface (32) of a second outer diameter smaller than the first outer diameter. The locking sleeve is axially moveable relative to the upper latch body (24) between a latching position and a release position. In the latching position, the latching surface (30) is in radial alignment with the balls (26), forcing the balls (26) radially outwardly into a latch seat (12) provided on a core barrel (20) attached to a lower end of a drill rod (14). This latches the assembly (10) to the core barrel preventing withdrawal.

Abstract: A pressure and temperature core sampler comprises a tool for recovering cores specifically enabling the evaluation of methane hydrate resources. Because methane hydrate tends to decompose under conditions of pressure decrease and/or temperature increase as the samples are retrieved to the surface, a coring tool in accordance with the present invention provides a self-contained system for retrieving core samples at or near in situ pressure while cooling the core sample. The coring tool is preferably a wire line retrievable device that provides for nearly continuous coring during the drilling operation.

Abstract: The drilling apparatus includes a wire line core barrel head assembly that has a latch body seatable on a drill string landing shoulder and retained in a latch seated position by a latch assembly spring urged to a latch seated position, fluid seals on the latch body to facilitate fluidly propelling the head assembly in an upward direction, valve mechanism in a latch body bypass channel to restrict fluid flow therethrough to provide a signal of the latch body seating on the landing shoulder and then opening together with being retractable to an open position by a latch retractor prior to the latch body being retracted and second valve mechanism to block axial outward flow in the bypass channel. The fluid seals are mounted to a latch body adaptor that may be removed to convert from an up-hole to a down-hole assembly.

Abstract: A pressure and temperature core sampler comprises a tool for recovering cores specifically enabling the evaluation of methane hydrate resources. Because methane hydrate tends to decompose under conditions of pressure decrease and/or temperature increase as the samples are retrieved to the surface, a coring tool in accordance with the present invention provides a self-contained system for retrieving core samples at or near in situ pressure while cooling the core sample. The coring tool is preferably a wire line retrievable device that provides for nearly continuous coring during the drilling operation.

Abstract: A pressure and temperature core sampler comprises a tool for recovering cores specifically enabling the evaluation of methane hydrate resources. Because methane hydrate tends to decompose under conditions of pressure decrease and/or temperature increase as the samples are retrieved to the surface, a coring tool in accordance with the present invention provides a self-contained system for retrieving core samples at or near in situ pressure while cooling the core sample. The coring tool is preferably a wire line retrievable device that provides for nearly continuous coring during the drilling operation.

Abstract: A pressure and temperature core sampler comprises a tool for recovering cores specifically enabling the evaluation of methane hydrate resources. Because methane hydrate tends to decompose under conditions of pressure decrease and/or temperature increase as the samples are retrieved to the surfaces a coring tool in accordance with the present invention provides a self-contained system for retrieving core samples at or near in situ pressure while cooling the core sample. The coring tool is preferably a wire line retrievable device that provides for nearly continuous coring during the drilling operation.