Hydrocarbon exploration history

Onshore prospecting and exploration operations started in western and central Latvia in the late 1950s. During 1958 – 1971, onshore 1-fold reflection seismic surveys were carried out, 12,000 line km altogether. Using seismic and deep drilling, several tens of local highs were discovered. At some of these highs, detailed seismic surveys were conducted; still, they were not investigated well enough.

One small oil deposit (Kuldiga) in the Cambrian sandstone was discovered so far (1963), as well as several small oil accumulations in the Ordovician deposits within several local highs where oil flows were encountered; several oil shows were observed.

In 1972, oil exploration in Latvia was interrupted, since such oil accumulations were considered insignificant in the former Soviet Union.

In 1986, exploration resumed due to the discovery of a new oil deposit in NW Lithuania not far from the Latvian border. At the same time, it became possible to use more accurate seismic methods. During 1986 - 1993, following CDP seismic (1,700 line km) and deep drilling, the structure of earlier discovered oil-prospective local highs was investigated in greater detail, several new local highs were discovered in SW Latvia. Still, there were no new oil discoveries. 

Offshore. Positive indications in the onshore coastal area stimulated exploration in the Baltic Sea, which commenced in 1976.

Most of the southern Latvian offshore was in the sphere of activities of CO PETROBALTIC, a group of companies then representing East Germany, Poland and USSR. In the rest of the Latvian offshore, all exploration activities were carried out by MINNEFTEPROM (Ministry of Oil Industry of USSR).

About 24,500 km of CDP seismic lines were acquired from 1976 to 1991, covering practically all the Latvian sector of the Baltic Sea by a 2x2 km seismic grid. Numerous structures have been identified, but only one of them, E6-1, was drilled by PETROBALTIC in 1984, discovering an oil accumulation in the Ordovician deposits. Another offshore well, P6-1, was drilled by MINNEFTEPROM in 1988. The well was drilled off-structure, as its main purpose was to test new drilling equipment.

After the restoration of the Latvian independence, the Latvian Geological Department continued offshore operations in 1991-92, carrying out detailed seismic investigations in the area close to the Swedish and Lithuanian border.

From 1993 on, due to insufficient funding, seismic and drilling operations were interrupted both onshore and offshore,  no new data were obtained since that time, except 2D seismic data (offshore, carred out 2006, about 200 km).