Abstract: A method for testing the nanomechanical properties of natural gas hydrate samples is provided. A dry pure nitrogen environment and a partial ultralow-temperature liquid nitrogen test condition are constructed, a micro-positive pressure state in a glovebox is maintained, and the temperature of a milling tool and a sample stand are maintained consistent; then, a hydrate sample is transferred and installed in the dry nitrogen environment, and the milling tool is driven to cut a surface of the natural gas hydrate sample to form a relatively flat surface; next, indentation parameter reliability testing is performed, an indentation load is changed, indentation testing of indentation points is performed, and an indentation form is observed. The method can realize indentation testing of natural gas hydrate samples in an ultralow-temperature and dry environment by means of a nanoindenter.

Abstract: A deep-sea crawling robot and a crawling method thereof are provided. The deep-sea crawling robot includes a crawling robot body and a countertop, wherein a top of the crawling robot body is fixedly connected to the countertop, left and right sides of a bottom of the crawling robot body are respectively provided with crawler belts, and left and right sides of the countertop are respectively provided with weight-increasing auxiliary crawling mechanisms; and an outer plate is fixedly connected to a front side or back side of the countertop, a multifunctional propelling mechanism is arranged on the outer plate, and a rapid dewatering mechanism is arranged in a chamber of the countertop. The deep-sea crawling robot can not only accelerate the propulsion and crawling speed when it is on the seabed but also further enhance its stability during the crawling process on the seabed.

Abstract: A bottom touching assisting device suitable for deep-sea submersibles and an implementation method thereof are provided. Four support columns are arranged within a mounting box body at a bottom of a deep-sea submersible, the support columns and the mounting box body are connected in a sliding manner through sliders, and the support column is sleeved with a threaded sleeve in a threaded connection manner. In conjunction with a drive component and a pressing mechanism, smooth vertical movement of the support column is achieved when the threaded sleeve rotates. This allows a bottom end of the support column to extend from the mounting box body.

Abstract: A concrete curing agent, a curing coating layer and a preparation method thereof, the concrete curing agent comprises a hardening agent and a hydrophobic agent, the raw materials of the hardening agent comprises the following raw materials in parts by weight: 0.1-10 parts of fluorosilicate salt and 100 parts of water, and the hydrophobic agent comprises the following raw materials in parts by weight: 0.1-10 parts of a base catalyst, 1-10 parts of a silane coupling agent, 0.1-10 parts of hydrogen-containing silicone oil, 5-10 parts of a cross-linking agent, 10-100 parts of silica sol and 100-1000 parts of water. The present invention can significantly improve the strength, hardness and hydrophobicity, impermeability and freeze-thaw resistance of surface of concrete before and after hardening, and effectively improves the service life of concrete structures.

Abstract: The present invention relates to disturbance on hydrate reservoirs with different buried depths, in particularly to a disturbance and stability analysis method for hydrate reservoirs with different buried depths. Preparing a series of stable hydrate systems parallel to a hydrate phase equilibrium curve, wherein both of the porosities and the hydrate saturations of various hydrate systems are consistent, but the buried depths are different; disturbing the series of hydrate systems prepared in the first step, conducting disturbance under different conditions aiming to the hydrate systems with different buried depths; analyzing the stability of the hydrate reservoirs.

Abstract: A self-adjusting hydraulic static penetrating device and method suitable for a seabed slope area is provided. The device includes an upper adjustable injection platform and a lower adjustable supporting platform. The upper adjustable injection platform is fixedly connected with the upper surface of the lower adjustable supporting platform. The upper adjustable injection platform includes a rack, a control cabin, an injection mechanism, a hydraulic station, a balance weight and first jacks. The control cabin, the injection mechanism, the hydraulic station, the balance weight and the first jacks are all arranged on the rack. The four first jacks are installed at the bottom of a steel structure frame, and the first jacks are fixed to the lower adjustable supporting platform. The device is simple in structure and low in cost, and can guarantee, to the maximum extent, that the overall gravity center of the device is always constant or slightly changes.

Abstract: A system and method for exploiting deepwater shallow low-abundance unconventional natural gas by artificial enrichment is provided. The system includes a metallogenic system, a transport system and a collection system. The metallogenic system is used for clustering and enriching the deepwater shallow low-abundance nonconventional natural gas to form a natural gas hydrate reservoir. The metallogenic system includes an artificial foundation pit and a dome cap covering the top of the artificial foundation pit. The transport system is used for transporting low-abundance natural gas in a deepwater shallow low-abundance nonconventional natural gas stratum to the metallogenic system to provide a gas source for synthesizing the natural gas hydrate reservoir for the metallogenic system. The transport system includes oriented communication wells connecting the artificial foundation pit and the deepwater shallow low-abundance nonconventional natural gas stratum and filled with gravel particles.

Abstract: The present invention discloses a silty marine natural gas hydrate gravel stimulation mining method and a mining device. The mining method appropriately relaxes the sand retention accuracy of a wellbore, so that the fine sand and muddy components of the stratum can flow into the wellbore, and after a certain period of production, the coarse gravels are injected into the extra-pipe stratum of the production well to fill the deficit caused by the production of the fine components of the stratum and the hydrates, and then the well is opened for production. The method achieves the triple objectives of improving the productivity of the silty reservoir, preventing the large-area deficit in the stratum and extending the effective period of the sand retention of the wellbore, by way of the alternation of the rounds of the gravel injection and the hydrate reservoir fluid extraction.

Abstract: A submarine shallow hydrate exploitation device, including an exploitation unit and a collection unit. The exploitation unit includes: a submarine ship working on a seabed; a drain chamber arranged on the submarine ship, wherein a pressure valve is arranged at a top of the drain chamber, one-way drain holes are formed in a bottom of the drain chamber, and water from massive hydrates is controlled to be discharged out of the drain chamber; a high-speed spiral bit configured to mine and convey sediments; a rotary ring arranged at an inlet end of the drain chamber and configured to connect the drain chamber with the high-speed spiral bit to provide rotation power for the high-speed spiral bit; a steering arm arranged on the submarine ship and configured to realize a rotation of the high-speed spiral bit; a crusher arranged on the submarine ship and configured to crush dried massive hydrates.

Abstract: A submarine shallow hydrate exploitation device, including an exploitation unit and a collection unit. The exploitation unit includes: a submarine ship working on a seabed; a drain chamber arranged on the submarine ship, wherein a pressure valve is arranged at a top of the drain chamber, one-way drain holes are formed in a bottom of the drain chamber, and water from massive hydrates is controlled to be discharged out of the drain chamber; a high-speed spiral bit configured to mine and convey sediments; a rotary ring arranged at an inlet end of the drain chamber and configured to connect the drain chamber with the high-speed spiral bit to provide rotation power for the high-speed spiral bit; a steering arm arranged on the submarine ship and configured to realize a rotation of the high-speed spiral bit; a crusher arranged on the submarine ship and configured to crush dried massive hydrates.

Abstract: The present invention discloses a silty marine natural gas hydrate gravel stimulation mining method and a mining device. The mining method appropriately relaxes the sand retention accuracy of a wellbore, so that the fine sand and muddy components of the stratum can flow into the wellbore, and after a certain period of production, the coarse gravels are injected into the extra-pipe stratum of the production well to fill the deficit caused by the production of the fine components of the stratum and the hydrates, and then the well is opened for production. The method achieves the triple objectives of improving the productivity of the silty reservoir, preventing the large-area deficit in the stratum and extending the effective period of the sand retention of the wellbore, by way of the alternation of the rounds of the gravel injection and the hydrate reservoir fluid extraction.

Abstract: An in-situ cultivation system of a deep-sea hydrothermal metallic sulfide deposits includes a hydrothermal metallic sulfide deposit mound body, a well casing, a well head control flow guide device, a fluid mixing control hood; the hydrothermal metallic sulfide deposit mound body includes a confining bed, a hydrothermal fluid enriching bed and mound body bedrock; perforations are formed at casing wall of the well casing; the well head flow control device is provided at top of the well casing; a lower opening is formed at bottom of the fluid mixing control hood and is sleeved on four sides of the top of the well casing; an upper opening is formed at top of the fluid mixing control hood; a plurality of fluid holes are formed at a lateral wall of the fluid mixing control hood; and a sulfide coating is applied to inner wall of the fluid mixing control hood.