Experimental device and method for accurately calculating hydrate content change in small volume sediments

Abstract

The invention discloses an experimental device and method for accurately calculating hydrate content change in small volume sediments. A small-volume reactor is connected with a standard gas chamber,and a stop valve is arranged between the two; two ends of a differential pressure transducer are respectively connected with the small-volume reactor and the standard gas chamber, and a gas pressure difference between the small-volume reactor and the standard gas chamber is measured by the differential pressure transducer; the small-volume reactor, the standard gas chamber and the differential pressure transducer are arranged in a temperature control module, and the temperatures of the three are controlled to be the same and constant by virtue of a temperature control module. The gas pressurevariation is measured by adopting the differential pressure transducer, and the differential pressure transducer is capable of easily measuring tiny gas pressure change caused by hydrate synthesis ordecomposition in the small volume sediments. High-resolution experimental data of molar content of hydrates in the synthesis and decomposition process can be easily obtained. According to the temperature control module, the influence of the temperature change on the gas pressure is effectively avoided, and the calculation accuracy of the hydrate content change is further ensured.

Description

technical field [0001] The invention belongs to the technical field of basic physical property testing of unconventional oil and gas reservoir engineering and geotechnical engineering, and specifically relates to an experimental device and method for accurately measuring and calculating the change of hydrate content in small-volume sediments. Background technique [0002] Natural gas hydrate is a cage-type crystalline compound formed by natural gas and water under specific temperature and pressure conditions. It is widely distributed in deep-water formations such as oceans and lakes and permafrost formations such as polar plateaus. The reserves are very huge and are considered to be 21 As one of the most important potential energy sources in the century, it has been highly valued by governments and research institutions at home and abroad. [0003] The depressurization method is the preferred method for trial production of natural gas hydrates. However, due to the poor perme...

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Problems solved by technology

[0004] At present, the volume of samples used in computed tomography experiments used to observe the pore-scale behavior of sediments is usually several cubic centimeters, resulting in insignificant gas pressure reduction caused by gas hydrate synthesis and gas pressure increase caused by gas hydrate decomposition. The pressure change measured by the pressure sensor is usually close to the measurement accuracy of the sensor, and the measurement error is large, so it is difficult to accurately control the hydrate saturation according to the gas pressure change in the process of depressurization and decomposition of natural gas hydrate

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