HEF utility explores for warm water with six wells

HEF veitur, a water and sewer utility, has had six exploratory wells drilled at Borgarfjörður eystri in a search for warm water, mbl.is reported. The wells were drilled in October, and measurements and analysis of the results are still under way, geologist Glúmur Björnsson said.

The wells are between 60 and 150 metres deep. One, drilled beside the town’s sports hall, was unsuccessful: it filled with acidic clay and mud, making it impossible to obtain a reliable temperature reading. Samples of the drill cuttings were collected from that hole.

Rhyolite, also known as liparite, characterises the wells farther inside the fjord, at Desjarmýri, Grund and Jökulsá. Basalt is more prominent farther out, near Háhamar and Grafningsgil. The hole by the sports hall contained alternating light and dark material.

At low-temperature geothermal areas, the heat that accumulates in a well after drilling is measured. Some of the wells at Borgarfjörður are completely dry, so it takes time for water to collect before measurements can be taken. Björnsson said the work is an initial investigation, not a search based on an expectation of finding a geothermal area. The aim is to find some warmth that would justify further exploration, or to stop if there is no sign of hot water.

The water would need to be above 10 degrees Celsius for the team to continue, he said. An existing well measures between 8 and 9 degrees at a depth of 100 metres, which is not warm enough to make further work promising.

Initial measurements have not shown significant anomalies or increased heat. Electrical conductivity is high in all the wells measured so far, Björnsson said, but that does not by itself indicate whether a well is good or bad.

Borbræður carried out the drilling for HEF veitur, which operates the water and wastewater systems in the urban settlement of Borgarfjörður eystri, including Bakkagerði. The utility is also responsible for emptying septic tanks in urban and rural areas.