Sweden’s Tethys Oil has completed an exploration well onshore Lithuania in northern Europe that the operator says could give a good indication of possible future shale prospectivity.

The explorer said a work program on the Skomantai-1 well in the Gargzdai license was completed, with the well now suspended to allow for additional work in the future. The rig is moving to another location on the license to drill a sidetrack in the Cambrian sandstone in an existing well.

The Skomantai-1 well had two objectives, Tethys said. The primary target was a previously undrilled oil prospect in the Cambrian sandstone near producing fields. The well also was drilled to evaluate the thick shale section overlaying the Cambrian sandstone for unconventional hydrocarbon potential. The well was drilled to a total measured depth of 2,431 m (7,976 ft). Oil was present in the Cambrian prospect target, but porosity was found to be insufficient to produce commercial quantities of oil.

An extensive data gathering also was carried out on the shale section, Tethys said. Electric logs were recorded and seven cores with a total combined length of 63 m (207 ft) were taken. The cores are being sent to a laboratory for analysis of various properties, including natural fracture, induced fracturing potential, porosity, permeability, source rock quality, and maturity. The well has been suspended to allow for future work on the shale section.

The Gargzdai license is owned by Lithuanian company UAB Minijos Nafta. Tethys has a 25% indirect interest through an agreement with Odin Energi A/S. Current production on the Gargzdai licence is in excess of 600 b/d of oil. In addition to the Gargzdai licence, Tethys holds interests in Lithuania in the non-producing Rietavas and Raiseiniai licenses.