Abstract: A method (60) of determining core orientation of a core sample (12) cut from the ground by a drill rig (10) having a drill string and a drill bit (20) coupled to a downhole end of the drill string. Drilling data (Cn, Rn) is continuously acquired while the drill rig (10) is operating to cut and retrieve the core sample (12). The drilling data is a combination of core orientation data Cn and rig operational data Rn, where the rig operational data is constituted by either one or both of: (a) near bit rig data Nn; and, (b) at surface rig data Sn. The drilling data is analyzed for a specific pattern of rig operational data Rn indicative of the core sample being broken from ground by operation of the drill rig (10). On detection of the specific pattern, the orientation of the core sample prior to being broken from the ground is the acquired core orientation data Cn coinciding with that specific pattern of rig operational data Rn.

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 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 and a plurality of ports intermediate opposite ends of the tool.

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 method (60) of determining core orientation of a core sample (12) cut from the ground by a drill rig (10) having a drill string and a drill bit (20) coupled to a downhole end of the drill string. Drilling data (Cn, Rn) is continuously acquired while the drill rig (10) is operating to cut and retrieve the core sample (12). The drilling data is a combination of core orientation data Cn and rig operational data Rn, where the rig operational data is constituted by either one or both of: (a) near bit rig data Nn; and, (b) at surface rig data Sn. The drilling data is analysed for a specific pattern of rig operational data Rn indicative of the core sample being broken from ground by operation of the drill rig (10). On detection of the specific pattern, the orientation of the core sample prior to being broken from the ground is the acquired core orientation data Cn coinciding with that specific pattern of rig operational data Rn.

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 core release system 10 has a housing 28 provided with an impact member 30 arranged to impact a core sample 16 gripped in a core tube 12. The housing 10 can be fitted over an end of the core tube 12 in which a core sample is gripped. The impact member is arranged to deform in preference to the core sample 16. By applying a force to the housing 28 or the tube 12 which causes impact of the core sample 16 on the impact member 28 the core sample is displaced relative to, and released from the grip of, the tube 12.

Abstract: A down hole running tool 14 travels in a first direction through a drill pipe for installing bit segments 18 at the end of a drive sub 12 attached to the drill pipe. The tool 14 includes a first portion 82 and a second portion 84 which is retractably coupled to a leading end of the first portion 82. The first portion 82 includes a tubular extension 134 which receives a spigot 136 that extends from an upper end of the second portion 84. A pin 138 extends transversely through the tubular extension 134 and resides within opposing slots 140 formed in the spigot 136. There is a stepped reduction in the internal diameter at the lower end of the tubular extension 134 so as to form a cup-like structure 146. A spring 168 is disposed about the spigot 136 and has an upper end seated in the cup-like structure 146 and a lower end bearing against an upper face 170 of the second portion 84. The spring 168 is biased so as to push the first and second portions 82 and 84 apart in the longitudinal direction.

Abstract: A retractable drill bit system for a ground drill includes drill bit assembly, a bit assembly sleeve, and a transport member. The drill bit assembly is engagable with a drive sub attached to the bottom of the ground drill with the drill bit assembly being selectively expandable and collapsible between a transport position in which the drill bit assembly is transported through the ground drill by the sleeve and transport member and a cutting position in which the drill bit assembly locks into the drive sub and cuts the hole. The drill bit assembly in the cutting position is able to cut a hole substantially greater than the diameter of the ground drill itself. The drill bit assembly includes a circular bit attached at a lower most end of the sleeve and bit segments retained in slots formed in the sleeve. Each segment is provided with a lever that extends radially inwardly of the sleeve and engages the transport member.

Abstract: A retractable drill bit system 10 comprises a drive sub 18 which is adapted for connection to a lower end of a drill 12, a tool 20 for installing and retracting drill bit segments 22 from the drive sub 18; and an insert 24 for selectively locking the bit segments 22 to an end of the drive sub 18 and releasing the bit segments 22. A plurality of recesses 5B are formed about an inner circumferential wall at one end of the drive sub 18 and a landing seat 32 formed about the inner wall upstream of the recesses 58. The area of the interior wall between the landing seat 32 and recesses 58 is profiled with a series of tapered and level surfaces. The tool 20 includes a slidable cradle 176 extending from one end about which the bit segments 22 are held during installation and retrieval. The bit segments 22 being held in place about the cradle by an elastic band 198.

Abstract: An insert for releasably retaining drill bit segments in a ground drill takes the form of a cylindrical tube movable within the ground drill between an installation position and a retrieval position. A pair of opposing tapered peaks extends from the upstream end of the insert. Sides of the peaks slope sharply in a downstream direction and lead to flats separating the peaks. When a running tool with radially extending latch dogs travels down the drill, the latch dogs contact the peaks to cause the tool to rotate about its longitudinal axis. When the latch dogs hit the flats they engage the insert, pushing it down into the installation position and locking the bit segments into a cutting position. Another set of latch dogs provided on the tool can engage slots formed in the insert to pull the insert upwardly and release the bit segments.

Abstract: A retractable drill bit system 10 comprises a drive sub 18 which is adapted for connection to a lower end of a drill 12, a tool 20 for installing and retracting drill bit segments 22 from the drive sub 18; and an insert 24 for selectively locking the bit segments 22 to an end of the drive sub 18 and releasing the bit segments 22.A plurality of recesses 5B are formed about an inner circumferential wall at one end of the drive sub 18 and a landing seat 32 formed about the inner wall upstream of the recesses 58. The area of the interior wall between the landing seat 32 and recesses 58 is profiled with a series of tapered and level surfaces.The tool 20 includes a slidable cradle 176 extending from one end about which the bit segments 22 are held during installation and retrieval. The bit segments 22 being held in place about the cradle by an elastic band 198.

Abstract: A retractable drill bit system 10 comprises a drive sub 18 which is adapted for connection to a lower end of a drill 12, a tool 20 for installing and retracting drill bit segments 22 from the drive sub 18; and an insert 24 for selectively locking the bit segments 22 to an end of the drive sub 18 and releasing the bit segments 22.A plurality of recesses 5B are formed about an inner circumferential wall at one end of the drive sub 18 and a landing seat 32 formed about the inner wall upstream of the recesses 58. The area of the interior wall between the landing seat 32 and recesses 58 is profiled with a series of tapered and level surfaces.The tool 20 includes a slidable cradle 176 extending from one end about which the bit segments 22 are held during installation and retrieval. The bit segments 22 being held in place about the cradle by an elastic band 198.

Abstract: A retractable drill bit system (10) comprises a drive sub (18) which is adapted for connection to a lower end of a drill (12), a tool (20) for installing and retractable drill bit segments (22) from the drive sub (18); and an insert (24) for selectively locking the bit segments (22) to an end of the drive sub (18) and releasing the bit segments (22). A plurality of recesses (5B) are formed about an inner circumferential wall at one end of the drive sub (18) and a landing seat (32) formed about the inner wall upstream of the recesses (58). The area of the interior wall between the landing seat (32) and recesses (58) is profiled with a series of tapered and level surfaces. The tool (20) includes a slidable cradle (176) extending from one end about which the bit segments (22) are held during installation and retrieval. The bit segments (22) being held in place about the cradle by an elastic band (198).