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High-pressure flood device for studying dynamic processes by highly resolved online conductivity measurements

An online conductivity measuring system was developed, to follow up quantitatively the hydrate growth in porous media by determining the changes of the salt concentration caused by the gas hydrate formation, and to study the accessibility of gas hydrates investigating the transport properties.

A novel high-pressure flow through conductivity cell based on a six lead circuitry was implemented for continuous conductivity measurements with a resolution < 0.01%. The pressure bearing part laid out for 70MPa is fabricated from corundum.

To operate at two phase flow conditions a low dead volume high-pressure gas/liquid-separator was developed and fabricated. A high-pressure degasser operates in series with a high-pressure gas/liquid separator. Regulating the flow rate of the liquid the pressure difference across a porous ceramic tube is controlled, so that the capillary threshold pressure is not exceeded. The response of the tracer detection equipment including the peak broadening by the gas/water separation exhibits a half width of only 0.4 cm3 under two phase flow conditions.

This device is universally usable for studies on processes in porous media under high pressure, which are accompanied with conductivity variations. (Technical drawings are available.)

The following conclusions can be drawn from the tracer experiments with porous media:
- The growth- and decomposition processes in the pore space are governed by transport phenomena.

- The symmetry of tracer elution profiles at the initial growth stage proves, that accessible liquids are involved during the growth of gas hydrates under single-phase flow. Stagnant liquid phases are not generated before the permeability is considerably reduced by gas hydrate formation.

- Under dual phase flow condition initial rapid growth of gas hydrates in the pore space decreases at an early stage due to the formation of transport barriers, gas hydrate films.

- Decomposition experiments prove, that stagnant liquids enriched with NaCl exist under dual phase flow.

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Agricolastrasse 10
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