Triaxial test device for in-situ generation and decomposition of natural gas hydrate

Abstract

The invention provides a triaxial test device for in-situ generation and decomposition of a natural gas hydrate. The device comprises a closed pressure chamber consisting of an outer cover barrel and a base; an inner cover barrel is arranged in the closed pressure chamber; the inner cover barrel is fixed on the base through a clamping ring; at least one oil inlet and outlet hole, at least one airinlet hole and at least one water inlet hole are formed on the base of the inner cover barrel; the oil inlet and outlet hole, the air inlet hole and the water inlet hole are formed on the inner cavity of the inner cover barrel; pistons are arranged on the tops of the outer cover barrel and the inner cover barrel; air exhaust holes are formed on the pistons; a lower pressure pad and an upper pressure pad which correspond to each other are arranged in the inner cavity of the inner cover barrel; the upper pressure pad corresponds to the positions of the pistons; and the lower pressure pad is fixed on the base.

Description

technical field [0001] The invention relates to a triaxial test device for in-situ generation and decomposition of natural gas hydrate, which belongs to the field of measurement of mechanical characteristics and basic physical properties of natural gas hydrate. Background technique [0002] As a clean energy with great potential, natural gas hydrate has the characteristics of large reserves, high energy density, wide distribution, and shallow burial. Its safe exploitation has become a new research hotspot in the oil and gas industry. The recovery of natural gas from gas hydrate deposits will reduce the strength of the seabed deposits, increase the instability of the seabed, and may cause geological subsidence, submarine landslides and other disasters. Spilled methane gas has a strong greenhouse effect and is a potential factor of global warming. In addition, during the exploration and production of hydrates, the drilling operation disturbs the geological structure of the hy...

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Problems solved by technology

The disadvantages of this method of preparing hydrate sediment samples outside the pressure chamber of the triaxial instrument are: 1) the sample preparation process will cause the decomposition of part of the hydrate, resulting in a low saturation of the sample hydrate; 2) mixed sample preparation The method cannot simulate the cementation state of seafloor hydrate sediments well, and cannot restore the formation process of seafloor hydrate; 3) This kind of triaxial instrument cannot control the decomposition process of hydrate during the test

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