Petroleum in Lower Palaeozoic rocks including Ordovician carbonate mounds and Cambrian sandstones is known from southern Scandinavia, northern Poland and the Baltic States. According to Sivhed (2004), around 100,000 cubic metres of oil was produced on Gotland from 1972-1992, and currently new wells are being drilled by Gripen Gas&Oil. Oil produced from early Palaeozoic reservoirs in the Baltic basin share many similarities and the accumulation process appears to be very complex as there is no definite answer about the main contributing source rock.
Key questions regarding the oil-source correlation in Baltic basin are:
The PhaseKinetic approach which includes a series of open- and close-system pyrolysis techniques provides a systematic way to evaluate the hydrocarbon generation properties of the source rocks. Besides GC-MS analysis on the biomarkers, FT-ICR MS which is very capable in identifying detail compositions of the oil is applied to screen the connection of source rock and oil in NSO compounds.