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.

In one aspect the present invention comprises a wireline retrievable coring apparatus for incorporation into a drillstring, comprising: a housing for coupling to a drill string housing, a drill bit, a turbine comprising a stator coupled to the housing and a rotor within the stator, the rotor coupled to rotate the drill bit, a core barrel through the turbine and in communication with the drill bit for capturing a core, a fluid path to the drill bit via the turbine to rotate the turbine, wherein the core barrel is rotationally isolated from the rotor and is fluidly isolated from the fluid path.

A system for the in-situ retained coring of a rock sample has a driving module (300), a retaining module (200), and a coring module (100) which are connected in sequence. The coring module (100) includes a rock core drilling tool and a rock core sample storage cylinder, the retaining module (200) includes a rock core sample retaining compartment. The driving module includes a coring drill machine that has a drill machine outer cylinder unlocking mechanism. The rock core drilling tool includes a coring drill tool, a core catcher (11), and an inner core pipe (12). The coring drill tool has an outer core pipe (13) and a hollow drill bit (14). The rock core sample retaining compartment has an inner coring cylinder (28), an outer coring cylinder (26), and an energy accumulator (229).

A drill bit comprises a first and a second body received within the first body. Each of the first body and second body has a respective crown, each crown having an inner and an outer operative circumference. The outer operative circumference of the second body and the inner operative circumference of the first body can define a first volume that can receive a tubular core sample. The second body can define a break surface that breaks the tubular core sample into core pieces. The drill bit can be employed in a borehole with a reverse circulation system that pumps fluid around an outer surface of the bit, and returning fluid can carry the core pieces out of the borehole.

A drill bit comprises a first and a second body received within the first body. Each of the first body and second body has a respective crown, each crown having an inner and an outer operative circumference. The outer operative circumference of the second body and the inner operative circumference of the first body can define a first volume that can receive a tubular core sample. The second body can define a break surface that breaks the tubular core sample into core pieces. The drill bit can be employed in a borehole with a reverse circulation system that pumps fluid around an outer surface of the bit, and returning fluid can carry the core pieces out of the borehole.

A core catcher for a coring tool may include a sleeve including a slit extending along at least a portion of a height of the sleeve. A crosspiece may extend at least partially across the at least one slit and at least partially around a perimeter of the sleeve. A track may extend at least partially around the perimeter of the sleeve, the crosspiece being slidably engaged with the track. The crosspiece and the track may be configured to cooperatively delimit relative movement of portions of the sleeve on opposite sides of the slit as a width of the slit increases or decreases responsive to receipt of a core sample into the core catcher.

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.

A method includes advancing a drill bit into a formation to form core sample pieces. The drill bit has a central axis and includes a crown defining an inner operative circumference. The crown is configured to form a core sample. A core receiving space is configured to receive the core sample as the drill bit is advanced into the formation. A base surface is spaced from the cutting face along the central axis of the drill bit. The base surface is configured to break apart portions of the core sample to form core sample pieces. The method can further include associating the core sample pieces with respective depths at which the core sample pieces were separated from the formation.

A core catcher for a coring tool, may include a sleeve including a slit extending along at least a portion of a height of the sleeve. A crosspiece may extend at least partially across the at least one slit and at least partially around a perimeter of the sleeve. A track may extend at least partially around the perimeter of the sleeve, the crosspiece being slidably engaged with the track. The crosspiece and the track may be configured to cooperatively delimit relative movement of portions of the sleeve on opposite sides of the slit as a width of the slit increases or decreases responsive to receipt of a core sample into the core catcher.

A drill bit comprises a first and a second body received within the first body. Each of the first body and second body has a respective crown, each crown having an inner and an outer operative circumference. The outer operative circumference of the second body and the inner operative circumference of the first body can define a first volume that can receive a tubular core sample. The second body can define a break surface that breaks the tubular core sample into core pieces. The drill bit can be employed in a borehole with a reverse circulation system that pumps fluid around an outer surface of the bit, and returning fluid can carry the core pieces out of the borehole.