Disclosed herein is a device and method for correlating core sample zones with an actual subterranean depth. The disclosed device has a pair of independent distance measuring devices operably in communication with a core sample apparatus where a first distance measuring device measures the length of a core sample entering a core sampling tube and a second distance measuring device measures a drive depth of the core sampling tube entering into the ground. A processing unit is provided for correlating the two distances so as to allow a determination as to the actual depth below ground from where a given zone of the core sample is extracted.

There is provided a wireline coring recovery system of a seafloor drilling rig, including: a winch, a rope, a submersible tension sensor, a cover, a main shaft and a catcher. One end of the rope is wound on the winch, and the other end of the rope is connected to an upper end of the catcher after the rope passes over a first pulley provided below the submersible tension sensor and then through a tapered hole on the cover. The catcher is provided in a center hole of the main shaft. The present application further provides a method of using the wireline coring recovery system. By the cooperation of the compression rod skewed teeth, the first rotating core skewed teeth, the second rotating core skewed teeth and the compression spring, the inner core barrel is readily recovered or released.

There is provided a wireline coring recovery system of a seafloor drilling rig, including: a winch, a rope, a submersible tension sensor, a cover, a main shaft and a catcher. One end of the rope is wound on the winch, and the other end of the rope is connected to an upper end of the catcher after the rope passes over a first pulley provided below the submersible tension sensor and then through a tapered hole on the cover. The catcher is provided in a center hole of the main shaft. The present application further provides a method of using the wireline coring recovery system. By the cooperation of the compression rod skewed teeth, the first rotating core skewed teeth, the second rotating core skewed teeth and the compression spring, the inner core barrel is readily recovered or released.

There is provided a wireline coring recovery system of a seafloor drilling rig, including: a winch, a rope, a submersible tension sensor, a cover, a main shaft and a catcher. One end of the rope is wound on the winch, and the other end of the rope is connected to an upper end of the catcher after the rope passes over a first pulley provided below the submersible tension sensor and then through a tapered hole on the cover. The catcher is provided in a center hole of the main shaft. The present application further provides a method of using the wireline coring recovery system. By the cooperation of the compression rod skewed teeth, the first rotating core skewed teeth, the second rotating core skewed teeth and the compression spring, the inner core barrel is readily recovered or released.

There is provided a wireline coring recovery system of a seafloor drilling rig, including: a winch, a rope, a submersible tension sensor, a cover, a main shaft and a catcher. One end of the rope is wound on the winch, and the other end of the rope is connected to an upper end of the catcher after the rope passes over a first pulley provided below the submersible tension sensor and then through a tapered hole on the cover. The catcher is provided in a center hole of the main shaft. The present application further provides a method of using the wireline coring recovery system. By the cooperation of the compression rod skewed teeth, the first rotating core skewed teeth, the second rotating core skewed teeth and the compression spring, the inner core barrel is readily recovered or released.

A pin point corer for collecting samples from a seabed of a sea, having a control unit to be positioned on a vessel or similar remote position, a top lift unit, which can be attached to a lifting and lowering unit of a vessel via an cable, such that it can be lifted and lowered relative to the seabed, a corer unit, releasable attached to the top lift unit by a fixation unit and arranged for being at least partly driven into layers of the seabed to collect the samples from there, e.g. when released from the top lift unit, wherein the top lift unit comprises a positioning unit bi-directionally communicating with the control unit for controlling the position of the corer unit. The invention also relates to a respective system and a method for collecting samples by use of such a pin point corer.

A pin point corer for collecting samples from a seabed of a sea, having a control unit to be positioned on a vessel or similar remote position, a top lift unit, which can be attached to a lifting and lowering unit of a vessel via an cable, such that it can be lifted and lowered relative to the seabed, a corer unit, releasable attached to the top lift unit by a fixation unit and arranged for being at least partly driven into layers of the seabed to collect the samples from there, e.g. when released from the top lift unit, wherein the top lift unit comprises a positioning unit bi-directionally communicating with the control unit for controlling the position of the corer unit. The invention also relates to a respective system and a method for collecting samples by use of such a pin point corer.

The present disclosure discloses a pressure-retaining cap screwing and unscrewing device for a marine natural gas hydrate pressure-retaining rock-core barrel, wherein it comprises a cap-unscrewing chuck, a support cylinder, a pressure-retaining cap screwing and unscrewing head, a spring, a screwing and unscrewing shaft, and a pressure-retaining cap screwing and unscrewing sleeve, a reducer and a motor; an input shaft of the reducer is connected to the motor, an output shaft of the reducer is the screwing and unscrewing shaft which is a tubular structure with a plurality of guide holes provided on a side wall thereof. The device is simple in structure, compact, light in weight, and convenient to control, and the pressure-retaining cap can be discarded.

The present disclosure discloses a pressure-retaining cap screwing and unscrewing device for a marine natural gas hydrate pressure-retaining rock-core barrel, wherein it comprises a cap-unscrewing chuck, a support cylinder, a pressure-retaining cap screwing and unscrewing head, a spring, a screwing and unscrewing shaft, and a pressure-retaining cap screwing and unscrewing sleeve, a reducer and a motor; an input shaft of the reducer is connected to the motor, an output shaft of the reducer is the screwing and unscrewing shaft which is a tubular structure with a plurality of guide holes provided on a side wall thereof. The device is simple in structure, compact, light in weight, and convenient to control, and the pressure-retaining cap can be discarded.

Disclosed is a sediment core-drilling process for a submarine wire-line coring drill rig, including 1) lowering the drill rig; 2) drilling in a pressure-suction mode; 3) drilling in a rotation-pressure-suction mode; 4) cutting sediment cores; 5) recovering a core inner tube; 6) cleaning bottom of hole; 7) punching before adding a drill pipe; 8) lowering another core inner tube; 9) adding the drill pipe; 10) punching after adding the drill pipe; 11) repeating the steps 2)-10) until a given hole depth is reached; 12) recovering the drill pipe and a wire-line coring outer tube drilling tool; 13) recovering the submarine wire-line coring drill rig. The core-drilling process provided herein is suited to working conditions without mud lubrication and mud protection for hole wall. This invention has advantages of low disturbance and high efficiency in coring and is suitable for remote operation.