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HE Résumé de rapport

Project ID: FIKW-CT-2001-00132
Financé au titre de: FP5-EAECTP C
Pays: Germany

Determination of gas and water release from the opalinus clay at ambient and elevated temperature

Water and gases such as carbon dioxide, hydro carbons, hydrogen, and hydrogen sulphide may be released from the Opalinus Clay at ambient and elevated temperatures.

The generated and released volatile components were determined at the existing physico-chemical conditions (temperature, humidity, pore pressure, mineralogical composition, etc.) of the test field, as a function of time.

In an additional laboratory programme, the gas generation and gas release was determined as a function of temperature from samples of the heated and unheated areas of the test field. These samples were taken by drilling before the dismantling of the heater.

The measurements on gas release in the test field indicated that already at mine temperature (14 °C) the hydrocarbons within the clay become oxidised, resulting in an increase of carbon dioxide and a decrease of oxygen. The release of helium originates from the a-decay of the uranium within the clay.

The fluctuation on the gas composition in the different boreholes results from the inhomogeneities of the Opalinus clay. The laboratory measurements at 100 °C indicated that mainly carbon dioxide and small amounts of hydro carbons are released at elevated temperature.

The investigation of samples taken from the test field after heater shut-down indicated that within the heating period of 18 months up to 50 °C, no significant alteration of the Opalinus clay with regard to gas and water content or mineralogical composition was observed. For much longer time periods within the temperature range up to 90 °C alteration cannot be excluded.

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Reported by

Theodor-Heuss-Strasse 4
38122 Braunschweig
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