A test device and test method for the mechanical properties of the interface between marine energy soil and structure containing natural gas hydrate

Abstract

The invention belongs to the field of geomechanical testing for marine energy exploitation, and in particular relates to a testing device and a testing method for the mechanical properties of the interface between marine energy soil and structure containing natural gas hydrate. The test device includes: a sealed pressure chamber, a pressure tank, a side loading shear, an axial loader, a temperature freezer and a data transmission acquisition processor. The side loading shears, the axial loader and the air pressure tank are respectively connected with the sealed pressure chamber to realize the application of gas pressure and the loading of different stress modes and different stress paths; the side loading shears and the axial loader are internally provided with The stress displacement sensor realizes the numerical acquisition of the axial and lateral stress displacement; the temperature refrigerator seamlessly surrounds the internal space of the sealed pressure chamber to realize the control of the experimental temperature; the data transmission and acquisition processor is respectively connected with the sealed pressure chamber and the lateral The loading shear, axial loader, temperature refrigerator, and air pressure tank are connected, and the test data is collected regularly and stored for processing. The device can realize the formation of natural gas hydrate, improve the accuracy of the hydrate-structure contact surface experiment, and provide good experimental technical support for the study of the hydrate-structure contact problem.

Description

technical field [0001] The invention belongs to the field of geomechanical testing for marine energy exploitation, and in particular relates to a testing device and a testing method for the mechanical properties of the interface between marine energy soil and structure containing natural gas hydrate. Background technique [0002] As a new type of clean energy, the exploitation of natural gas hydrate has gradually received more and more attention. Natural gas hydrate energy soil is usually formed in the loose sediments of deep-water shallow overburden, which has poor diagenesis and low shear strength, and hydrates play an effective cementing role in the pores of the sedimentary layer; This leads to a significant reduction in the stratum strength and bearing capacity, causing the deformation of the stratum around the production well, which in turn affects the interaction between the soil and the wellbore structural plane, and even causes geological disasters such as wellbore i...

AI Technical Summary

Problems solved by technology

Natural gas hydrate energy soils are usually formed in loose sediments in deep-water shallow overburden layers, with poor diagenesis and low shear strength, and hydrates play an effective role in cementing in the pores of sedimentary layers; during the mining process, hydrates decompose As a result, the strength and bearing capacity of the formation are greatly reduced, and the formation around the production well is deformed, which in turn affects the interaction between the soil and the structural surface of the wellbore, and even causes geological disasters such as wellbore instability, submarine landslides, and sea surface subsidence; The research on hydrate mining mainly focuses on productivity evaluation, ignoring the evaluation of hydrate formation and wellbore stability; therefore, it is of great significance to carry out research on the mechanical properties of the interface between soil and structure of marine energy containing gas hydrates.

[0003] The study of the mechanical properties of the contact surface between soil and structure is one of the important topics in the study of soil mechanics. Tan Junkun and Guo Jiaqi et al. have patented "A Shear Instrument for Measuring the Mechanical Properties of the Contact Surface between Soil and Structure" (Application No. 201720353735.1 ) and the patent "A Visual Layered Shear Box for Shear Tests on Soil-Structure Interfaces" (Application No. 201720220316.0) provide a shear instrument for measuring the mechanical properties of soil-structure interface surfaces and a A visual layered shear box for shear tests of soil-structure interfaces; however, these two devices cannot generate soil samples containing gas hydrates, the axial stress is not directly applied to the interface, and the structure and structure There is no device to reduce friction between the soil containers, the friction between the soil container and the structure is relatively high, and the structure surface is kept flush with the opening of the shearer, and the influence of the volume change of the test soil sample during the shearing process is not considered, so it cannot Ensure that the test soil sample is always in contact with the structure surface, which reduces the accuracy of the experiment; therefore, the above-mentioned device is not suitable for studying the mechanical properties of the contact surface between marine energy soil and structure containing gas hydrate

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