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.

The present document relates to a piston corer for acquiring a soil sample. The piston corer comprises a sample reception cylinder for taking in and retaining the soil sample, and which comprises a piston. The piston is moveable over a piston stroke inside the sample reception cylinder. An intake opening at a first end of the sample reception cylinder allows to receive the soil sample upon penetration of the ground, and the piston is configured to move in a direction away from the intake opening during taking in of the soil sample towards an end position of the piston stroke. The piston corer further comprises an activator cooperating with a valve arranged for closing of the intake opening upon activation. The activator is configured for activating a closing action of the valve in response to the piston reaching the end position of the piston stroke. The document further relates to a method of acquiring a soil sample using such a piston corer.

A natural gas hydrate pressure-retaining corer includes an outer tube assembly and an inner tube assembly installed inside the outer tube assembly. The inner tube assembly includes a first inner tube assembly and a second inner tube assembly. The first inner tube assembly includes a spearhead, a latching device, a suspension plug, a hydraulic piston tube, a piston short limit short section, a limit copper pin, a sealing head, a middle tube, a weight tube drive mechanism and a pressure-retaining ball valve closing sealing mechanism which are sequentially connected from top to bottom. The second inner tube assembly includes a piston compensation balance mechanism, a single-action mechanism, an accumulator mechanism, a sealing mechanism and a core barrel connected sequentially from top to bottom.

A natural gas hydrate pressure-retaining corer includes an outer tube assembly and an inner tube assembly installed inside the outer tube assembly. The inner tube assembly includes a first inner tube assembly and a second inner tube assembly. The first inner tube assembly includes a spearhead, a latching device, a suspension plug, a hydraulic piston tube, a piston short limit short section, a limit copper pin, a sealing head, a middle tube, a weight tube drive mechanism and a pressure-retaining ball valve closing sealing mechanism which are sequentially connected from top to bottom. The second inner tube assembly includes a piston compensation balance mechanism, a single-action mechanism, an accumulator mechanism, a sealing mechanism and a core barrel connected sequentially from top to bottom.

The present invention discloses a system for measuring the mechanical properties of sea floor sediments at full ocean depth. The system includes an overwater monitoring unit and an underwater measurement device, where the underwater measurement device includes an observation platform and a measuring mechanism; the observation platform includes a frame-type body and a floating body, a wing panel, a floating ball cabin, a leveling mechanism, a counterweight, and a release mechanism mounted on the frame-type body; the floating ball cabin seals a circuit system; the leveling mechanism adjusts the underwater measurement device horizontally on the sea floor when the frame-type body reaches the sea floor; the release mechanism discards the counterweight for recovery of the unit after the underwater measurement device completes the underwater operation; the measuring mechanism includes at least one of a cone penetration measuring mechanism, a spherical penetration measuring mechanism, and a vane shear measuring mechanism, or a sampling mechanism.

The present invention relates to a natural gas hydrate rotary pressure-retaining corer, including an outer tube assembly and an inner tube assembly installed inside the outer tube assembly. The inner tube assembly includes an inner tube assembly a and an inner tube assembly b. The inner tube assembly a includes a spearhead, a latch mechanism, a long tube, a middle tube sub, a short joint, a sealing sub, a connecting tube, a middle tube and a pressure-retaining ball valve closing sealing mechanism connected sequentially from top to bottom. The inner tube assembly b includes a lifting device, a latch suspension mechanism, an spirol pin sub, a single-action mechanism, a dapter, an adjustment joint, a connecting tube, a sealing mechanism, a connecting long tube, a connecting long tube sub and a core barrel connected sequentially from top to bottom.

Core sampling is enabled over a wide range of areas of the seabed. The present device is provided with a main robot that is moved underwater by remote operation, and a sampling robot that is connected to a manipulator that is attached to the main robot, and that can move in relation to the seabed. The sampling robot is provided with a core tube for excavating the seabed by being rotated and propelled, introducing into the core tube a core of the seabed by the excavation, and breaking the introduced core into core pieces. The main robot is provided with a core rack for storing the core pieces taken from inside the core tube.

Core sampling is enabled over a wide range of areas of the seabed. The present device is provided with a main robot that is moved underwater by remote operation, and a sampling robot that is connected to a manipulator that is attached to the main robot, and that can move in relation to the seabed. The sampling robot is provided with a core tube for excavating the seabed by being rotated and propelled, introducing into the core tube a core of the seabed by the excavation, and breaking the introduced core into core pieces. The main robot is provided with a core rack for storing the core pieces taken from inside the core tube.

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.