Triaxial test device for testing transubstantiation of sediments of gas hydrate

Abstract

The invention provides a triaxial test device for testing the transubstantiation of sediments of a 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; at least two oil inlet / outlet holes are formed on the base; the opening of one oil inlet / outlet hole is formed on a circular cavity between the outer cover barrel and the inner cover barrel; the opening of the other oil inlet / outlet hole is formed on an inner cavity of the inner cover barrel; pistons are arranged on the tops of the outer cover barrel and the inner cover barrel; 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 measuring the deformation of natural gas hydrate deposits, which belongs to the field of measuring the 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 hydra...

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Problems solved by technology

[0004] In recent years, some research institutes have used the conventional triaxial instrument of soil mechanics to carry out the research on the variable measurement of gas hydrate deposits. Generally, the triaxial instrument with single pressure chamber is used. The disadvantage of this kind of variable measurement device of natural gas hydrate deposit is : 1) It is only suitable for volume change measurement under low confining pressure conditions, and cannot simulate the true stress state of seabed hydrate deposits and volume changes under pressure

; 2) There is a pressure difference between the inside and outside of the single pressure chamber, on the one hand, it will cause the leakage of hydraulic oil in the pressure chamber, on the other hand, it will cause the deformation of the pressure chamber, which will affect the accuracy of volume change measurement

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