Geothermal fluid sampling for tracer analysis of isotopes such as tritium and 125I — (131I) in both vapour and liquid systems is done through a condensation process of the fluid, as shown in Fig. 15.

Steam pipe to turbin

Condenser

Master valve

Condenser sampling

valve sampling

FIG. 15. Schematic diagram of a condenser used for sampling in geothermal wells in Indonesia.

The sampling procedure is as follows:

• The condensation of the geothermal fluid is achieved using the condenser apparatus shown in Fig. 15.

• The condenser is connected to the well head. Cool water flows into the condenser countercurrent to the geothermal fluid which is transported in the spiral tube.

• The valve at the well head is opened to allow hot fluid to flow into the condenser.

• Water from the vapour or hot liquid is condensed to ambient temperature. This water is collected in a plastic bottle of 1 L or 2 L capacity.

Sampling in the Philippines (at the Energy Development Corporation) makes use of a Weber separator, where steam and water are separated during sampling. In the Philippine geothermal fields, the Weber separator is connected along two phase lines (shown in Fig. 16) and samples are collected separately for water and steam condensate.