Fuzhou University

Xuezhen Wu

Yujing Jiang

Tao Deng

Zhenchang Guan

Dayong Li

Sihong Liu

Gang Wang

Qing Ye

A self-entry exploitation device and method for marine natural gas hydrates is provided. The exploitation device includes a self-entry structural body (), a sand control device () and a gas-liquid lifting system. The self-entry structural body () is a gravity anchor. The sand control device () and the gas-liquid lifting system are mounted on the self-entry structural body (). At least one cavity () is formed between the self-entry structural body () and the sand control device (), and the cavity () is communicated with at least one channel. The sand control device () allows liquid and gas to pass through to enter the cavity () and is able to filter out silt. The gas-liquid lifting system includes at least one lifting power device () and has an end connected to the cavity () and an end extending out through a pipeline. By adoption of the exploitation device, drilling is not needed, the self-entry structural body () can enter a natural gas hydrate reservoir or a free gas layer below the natural gas hydrate reservoir, so that depressurizing exploitation can be realized, an exploitation system can be withdrawn, and the exploitation cost of natural gas hydrates can be greatly reduced.

Self-entry exploitation device and method for marine natural gas hydrates

The invention discloses a suction cylinder exploitation device and method for marine natural gas hydrates. The exploitation device comprises an exploitation cylinder, a water pump, a sand control device, a liquid-gas filling system and the like. Through the specially-designed exploitation cylinder and mating devices thereof, the exploitation cylinder can sink below a seabed surface to exploit natural gas hydrates deep below the seabed surface and can be withdrawn. A series of problems such as high well drilling and completion cost of traditional deep-sea drilling exploitation methods, and damage, collapses and sand generation of plain concrete wellbores under the effect of formation pressure are solved, and the limitations that traditional capping depressurization methods can only exploit submarine superficial hydrates and are low in exploitation efficiency are overcome. The invention can greatly reduce the exploitation cost of natural gas hydrates deep below the seabed surface and is of great significance for commercial exploitation of marine natural gas hydrates.

Suction cylinder exploitation device and method for marine natural gas hydrates

The present invention relates to a support method of preset internal cable for in-situ tunnel expansion project, comprising a cable, lockset and an anchoring agent, wherein before the excavation of the newly-built tunnel, a borehole is drilled into the surrounding rock from the in-situ tunnel, and the cable is installed in the borehole and pre-stressed, so as to play a supporting role at the moment of excavation of the newly-built tunnel. The cable is fixed in the depth of the surrounding rock by the anchoring agent, and the lockset of the cable is set at the position of the excavation contour line of the newly-built tunnel inside the surrounding rock. The present invention provides a method that does not interfere with the excavation construction and can effectively support the surrounding rock of the expanded tunnel in advance. It breaks through the 'excavation first and then supports' model in the previous tunnel construction, and uses the space of the in-situ tunnel for pre-support, and by applying prestress, the deformation of surrounding rock can be controlled to the maximum extent.

Support method of preset internal cable for in-situ tunnel expansion project

The present disclosure relates to a construction method for a deformable anchor cable capable of being prestressed. The anchor cable includes an outer sleeve, a shrinkage pipe, an inner sleeve, a steel strand, an anchor and a tray. When the anchor cable is in use, a hole is drilled first, then the anchor cable is mounted in the drilled hole, and finally a prestress is applied to the steel strand of the anchor cable. According to the construction method, the construction is convenient; the anchor cable has the characteristics of high strength and large deformation, and can be easily prestressed; and the large deformation is realized by squeezing the inner sleeve by means of the anchor, which completely overcomes the problem of breaking a cold-drawn rod during the large deformation process.

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Fuzhou, China

Xuezhen Wu