Apparatus for in-situ measurement of gas content in subsea aerosol and its measurement method

Abstract

The invention discloses a device applied to in-situ measurement of gas content in seabed gas-containing soil and a measurement method of the device. The device comprises a metal shell, a metal inner container, an upper top plate, a movable door, a hydraulic jack, a displacement sensor, an electromotor and a single-chip microcontroller, wherein a soil inlet is formed in the side wall of the metal shell; the movable door is arranged between the metal shell and the metal inner container; an oil cylinder of the hydraulic jack is fixed at the top end of the metal shell; the upper top plate is fixedly mounted at the lower part of a piston rod of the hydraulic jack; the electromotor is mounted on the upper top plate and drives the movable door; the displacement sensor is used for measuring the displacement of the upper top plate. Through the device, the problems of high uncertainty and incapability of quantizing errors of the existing gas content measurement method can be solved; the device supplies key parameters to safe design of offshore foundations (such as offshore oil and gas platform foundations and offshore wind power foundations) on gas-containing soil sea beds which are widely distributed in sea areas such as Pearl River Delta, Yangtze River Delta, and Bohai Baye in China.

Description

technical field [0001] The invention belongs to the technical field of seabed soil mechanical property detection, and relates to a device for in-situ measurement of gas content in seabed gas-bearing soil and a measurement method thereof. Background technique [0002] More than 70% of the world's oil and gas resources are stored in the seabed. Oil and gas exploration and exploitation are completely dependent on offshore drilling platforms. The drilling platform bears loads such as offshore typhoons and huge waves. These loads are transferred to the seabed through the drilling platform's pile foundation or mooring positioning system. Therefore, the stability of the drilling platform depends on the mechanical properties (especially strength, stiffness) of the seabed. Weak seabeds rich in biogas are widely distributed in my country's Pearl River Delta, Yangtze River Delta, Bohai Bay and other sea areas (that is, the seabed soil contains a large number of isolated air bubbles)...

AI Technical Summary

Problems solved by technology

If the air-bearing soil is taken out from the seabed and measured in a laboratory on land, the volume of the air bubbles in the soil will expand sharply with the sudden drop of the external pressure of the soil, so that the measurement results cannot truly reflect the in-situ air content.

The traditional in-situ gas-bearing test method (experimentally estimating the gas content based on the velocity of sound waves propagating in the seabed air-bearing soil) is an indirect test method, which has the problems of strong uncertainty and unquantifiable errors

At present, there is no instrument that can directly measure the amount of gas in aerobic soil directly on the seabed.

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