Abstract: A test system and a test method for replacing natural gas hydrate with carbon dioxide are disclosed, relating to the technical field of exploitation of natural gas hydrates. The test system comprises a sample reaction vessel, a sample boundary condition loading device, a methane gas supply device, a carbon dioxide gas supply device, an output article collection and measurement device, and a data acquisition control device. A sample-sealing rubber sleeve and an upper sample-sealing plate are arranged in an inner cavity of the vessel, the sample-sealing rubber sleeve, a lower tray and the upper sample-sealing plate form a sample-sealing space. An axial pressure loading plate is arranged on the upper sample-sealing plate, and an upper cover plate is provided with an axial pressure loading injection hole. A side shrouding is provided with a confining pressure loading injection hole and a product discharge hole.

Abstract: A multi-stage perforation and shock wave combined device and method for initial fracture enhancement are provided. The multi-stage perforation and shock wave combined device for initial fracture enhancement includes a perforating gun and a shock wave excitation nipple, where the perforating gun is configured to fire perforating bullets into a formation to form initial fractures; the shock wave excitation nipple is connected to the perforating gun, and includes an energetic rod capable of exploding after excitation and a feeding assembly; the feeding assembly includes a pushing head, a reciprocating spring, and a feeding spring; and the reciprocating spring is configured to push the pushing head, so as to push a spare energetic rod into a target position.

Abstract: A rock mechanics triaxial testing machine includes an outer pressure chamber and an inner pressure chamber located inside the outer pressure chamber, and a side wall of the inner pressure chamber is provided with a communication hole communicating with the outer pressure chamber; an upper pressure head and a lower pressure head which may be placed inside the inner pressure chamber; an axial pressure driving member, the axial pressure driving member may drive the upper pressure head and lower pressure head to approach each other to squeeze the rock sample; an axial deformation sensor, a radial deformation sensor, a lifting mechanism, the lifting mechanism may drive the inner pressure chamber to rise and fall. In the rock mechanics triaxial testing machine, the inner pressure chamber and the outer pressure chamber are nested indoors and outdoors, and the inner pressure chamber is used to quickly mount rock test samples.

Abstract: A method for recycling a lithium iron phosphate positive plate with low energy consumption and low Al content, including: crushing a lithium iron phosphate positive plate to be recycled into a granular material with a particle size of 1-15 mm by using a crusher; heating the granular material obtained in step (1) to 350-500° C. in an atmosphere furnace in an inert atmosphere; and keeping the granular material at 350-500° C. for 0.5-2 h followed by cooling to a preset temperature to obtain a calcined product; grinding the calcined product obtained in step (2) by using a grinder to obtain a ground product with D50 larger than or equal to 50 ?m; and classifying the ground product obtained in step (3) by using an air classifier to remove Al simple substance to obtain a recovered positive material with an Al content below 200 ppm.

Abstract: A method for exploiting a natural gas hydrate reservoir includes drilling a borehole entering the natural gas hydrate reservoir; perforating the borehole to form perforations; fracturing the natural gas hydrate reservoir via the perforations by using a gas containing calcium oxide powder having a particle size 0.001 to 10 mm to generate a fracture; and collecting natural gas released by the natural gas hydrate. The method is easy to operate, cost-effective, and suitable for commercial applications.

Abstract: A device and a method for transferring and storing a deep in-situ core in a sealed and pressure-maintaining manner includes a pressure vessel, a sealed storage vessel, a control system, a pressure regulation system and at least one spherical valve. The pressure vessel includes a first barrel and a first end sealing piston mounted at a first end of the first barrel and being slidable in the pressure vessel. The sealed storage vessel includes a second barrel and a second end sealing piston which is mounted at a first end of the second barrel. At least one spherical valve is connected between the first barrel and the second barrel. The pressure regulation system is configured for regulating an amount of water in the second barrel. The control system includes a first pressure sensor, a second pressure sensor, and a controller.

Abstract: A drilling method and a drilling apparatus are provided. In the method, the feature parameter of the stratum around the well, the feature parameter of the stratum in front of the drill bit, the preset drilling parameter, the preset trajectory parameter, the current pose of the drill bit and the current rate of penetration of the drill bit are obtained; the feature parameter of the reservoir in front of the drill bit is determined based on the feature parameter of the stratum around the well and the feature parameter of the stratum in front of the drill bit; the above parameters are inputted to the pre-trained drilling parameter modification model to obtain drilling trajectory parameter and drilling speed parameters; and the drilling direction and the rate of penetration are regulated based on the above parameters.

Abstract: A device and a method for transferring and storing a deep in-situ core in a sealed and pressure-maintaining manner includes a pressure vessel, a sealed storage vessel, a control system, a pressure regulation system and at least one spherical valve. The pressure vessel includes a first barrel and a first end sealing piston mounted at a first end of the first barrel and being slidable in the pressure vessel. The sealed storage vessel includes a second barrel and a second end sealing piston which is mounted at a first end of the second barrel. At least one spherical valve is connected between the first barrel and the second barrel. The pressure regulation system is configured for regulating an amount of water in the second barrel. The control system includes a first pressure sensor, a second pressure sensor, and a controller.

Abstract: A rock mechanics triaxial testing machine includes an outer pressure chamber and an inner pressure chamber located inside the outer pressure chamber, and a side wall of the inner pressure chamber is provided with a communication hole communicating with the outer pressure chamber; an upper pressure head and a lower pressure head which may be placed inside the inner pressure chamber; an axial pressure driving member, the axial pressure driving member may drive the upper pressure head and lower pressure head to approach each other to squeeze the rock sample; an axial deformation sensor, a radial deformation sensor, a lifting mechanism, the lifting mechanism may drive the inner pressure chamber to rise and fall. In the rock mechanics triaxial testing machine, the inner pressure chamber and the outer pressure chamber are nested indoors and outdoors, and the inner pressure chamber is used to quickly mount rock test samples.

Abstract: The present disclosure provides a device and a method for preparing natural gas hydrate under controlled temperature and pressure, which relates to the technical field of rock and soil mechanics test technology and equipment. The device includes a three-axis cylinder outer tube, a temperature adjustment system, a pressure loading system, a gas supply system and a recovery system. The three-axis cylinder outer tube is provided with an accommodating cavity throughout its middle, and the accommodating cavity is provided with an end cover of the three-axis cylinder outer tube at each end thereof. The temperature adjustment system is used to adjust the temperature of the three-axis cylinder outer tube. The pressure loading system is used to apply pressure load to the accommodating cavity. The gas supply system is used to supply a high-pressure gas into the accommodating cavity. The recovery system is used to recover the moisture and gas in the accommodating cavity.

Abstract: A method for recycling a lithium iron phosphate positive plate with low energy consumption and low Al content, including: crushing a lithium iron phosphate positive plate to be recycled into a granular material with a particle size of 1-15 mm by using a crusher; heating the granular material obtained in step (1) to 350-500° C. in an atmosphere furnace in an inert atmosphere; and keeping the granular material at 350-500° C. for 0.5-2 h followed by cooling to a preset temperature to obtain a calcined product; grinding the calcined product obtained in step (2) by using a grinder to obtain a ground product with D50 larger than or equal to 50 ?m; and classifying the ground product obtained in step (3) by using an air classifier to remove Al simple substance to obtain a recovered positive material with an Al content below 200 ppm.

Abstract: The present invention discloses an exploiting structure for a natural gas hydrate reservoir, comprising: a drilling well located in the natural gas hydrate reservoir; and a fractured fracture provided in communication with the drilling well, which is located in the natural gas hydrate reservoir and in which a gas containing calcium oxide powder is provided. In the present invention, the calcium oxide powder is filled with the fractured fracture by means of the gas. Then, the natural gas hydrate in the fractured fracture is decomposed, and the water generated from the decomposition reacts with the calcium oxide to release a large amount of heat, and a high-porosity calcium hydroxide filler can be formed. The exploiting method provided in the present invention is simple and easy to operate, and has low exploitation costs, and is suitable for commercial promotion and application.

Abstract: A visualization system for simulating excavation of a fluid-structure interaction tunnel includes a fluid-structure interaction tunnel model system, a tunnel model solution supply system, a detection system and an excavation system. The tunnel model solution supply system is configured to inject a nuclide solution to simulate a fluid pressure. The detection system is configured to detect a 3D deformation state of a tunnel surrounding rock and a 3D migration process of the nuclide solution. The excavation system is provided between the detection system and the tunnel model system to simulate tunnel excavation. During the tunnel excavation, a lifting device in the excavation system controls a drilling device to ascend to a set height for operation. During 3D detection, the lifting device controls the drilling device to descend to an initial height to avoid affecting the detection of a detection device.

Abstract: A visual test system for a secondary generation or decomposition of a hydrate includes a hydrate conveying device, a computerized tomography (CT) imaging device, a temperature control device, a pressure control device and a flow control device. The hydrate conveying device includes an annular pipeline structure composed of a plurality of straight pipeline sections and a plurality of curved pipeline sections. The straight pipeline section is able to rotate around an axis thereof under the drive of a pipeline driving device. The CT imaging device is used to perform a three-dimensional (3D) detection inside the pipeline, and includes a turntable, a ray source and a detector. The ray source is able to rotate under the drive of the turntable driving device. The temperature control device, the pressure control device and the flow control device are used to control a gas-liquid mixture's temperature, pressure and flow rate, respectively.

Abstract: A triaxial rock mechanics test system for high-strain-rate cyclic dynamic loading is provided, including: a host loading module, a dynamic cyclic loading module, and a dynamic measurement module. The host loading module includes a loading frame, a triaxial pressure mechanism and an actuator that are provided inside the loading frame. The dynamic cyclic loading module includes a driving mechanism, a fixed mechanism and a mobile mechanism. The dynamic measurement module is configured to acquire axial pressure data, radial deformation data and axial deformation data of the rock sample during a test. In the triaxial rock mechanics test system for high-strain-rate cyclic dynamic loading of the present invention, an energetic rod is driven by an electrical explosion of a metal wire to generate a strong shock wave with controllable peak pressure, duration and waveform.

Abstract: A visible test system includes a test chamber system, a heating system, a pressure control system, and a high-energy accelerator CT detection system configured to scan and detect the seepage and migration of magnetic fluid in fractures in a sample. The test chamber system includes a pressure chamber and a sample encapsulation device immersed in hydraulic oil arranged inside the pressure chamber. The heating system includes a magnetic fluid heating device, a resistance wire heating device and a temperature detection device. The magnetic fluid heating device includes a magnetic fluid loading pump configured to supply the magnetic fluid injected into the sample encapsulation device and an alternating magnetic field control device configured to provide an alternating magnetic field for heating the magnetic fluid. The resistance wire heating device is configured to heat the hydraulic oil. The present invention makes the fracture connectivity change during rock mass fracture visible.

Abstract: The present invention improves the precision in observing cracks in rocks during a hydraulic fracturing test, improving a scientific understanding of the regular pattern of development cracks in of hydraulically fractured rocks. The technical solution includes: hydraulically fracturing the rock with aqueous solutions containing an interventional contrast-enhanced agent, forming hydraulically fractured cracks, wherein the difference in a mass attenuation coefficient ?/? of x-rays between the cracks and the rock is improved by the interventional contrast-enhanced agent in the cracks, moreover, the difference in mass energy absorption coefficient ?en/? of x-rays between the cracks and the rock is improved, then the linear attenuation coefficient of the reception of the detector is changed, improving the imaging resolution for hydraulically fractured cracks in the rock.

Abstract: A method for imaging three-dimensional topography with high precision, which overcomes the disadvantage and deficiency of low precision in observing three-dimensional topography of hydraulically fractured cracks of rocks, improve the precision in observing three-dimensional topography of cracks in rock hydraulic fracturing test, and benefit for scientifically understanding regular pattern of development of hydraulically fractured cracks of rocks.

Abstract: A method for enhanced interventional imaging for cracks, improving the precision in observing cracks in rock hydraulic fracturing test, benefiting for scientifically understanding regular pattern of development of hydraulically fractured cracks in rocks. The technical solution comprises: hydraulically fracturing the rock with aqueous solutions containing nanoscale interventional contrast-enhanced agent which has a high atomic number; forming hydraulically fractured cracks, wherein the difference in mass attenuation coefficient ?/? of x-ray between the cracks and the rock is improved by the interventional contrast-enhanced agent in the cracks, moreover, the difference in mass energy absorption coefficient ?en/? of x-ray between the cracks and the rock is improved, then the linear attenuation coefficient of the reception of detector is changed, improving the imaging resolution for hydraulically fractured cracks in the rock.