Potential resources of the prospective Lower Paleozoic shale formations in the belt stretching from Gdansk Pomerania (including the adjacent Baltic area) to the Lublin Region were assessed by PGI-NRI Report of 2012.
Total most probable recoverable gas resources were estimated at 0.35-0.77 Tcm, while according to the USGS report of the same year the resources are lower by an order of magnitude. Interestingly enough, the two reports use the same methodology which is based on estimated ultimate recovery (EUR) from a well that drains a particular area of the prospective shale formation. A much smaller area of prospective shale formations and more conservative estimates of ultimate recovery per well were assumed in the report by USGS.
On the other hand, EIA/ARI reports of 2011 and 2013 are based on a totally different methodology. Instead of EUR per well, coefficients of resource recovery (e.g. 20% of the total technically recoverable resources), contingent on basin geology and reservoir conditions were applied. According to these reports, gas resources are higher by an order of magnitude (5.3 and 4 Tcm, respectively) comparing to the PGI-NRI report.
Nevertheless, the coefficients seem to be slightly too high, considering the geology of Poland. This, in addition to a much wider area taken into account (including basins in south and west Poland, which were not considered by PGI-NRI and USGS), may well explain these significant disparities.
Considering the above, the assessments of Poland's technically recoverable resources are still hypothetical, while the estimates of the PGI-NRI report of 2012 seem to be the most credible and best documented ones.
As of today, there is no reliable information on Poland's potential commercial shale gas reserves. Production tests delivered in hundred or more planned wells will be required to establish the areas in Poland's shale basins that are suitable for economically viable gas production. In addition, data coming from new wells will help to firm up the estimates of recoverable resources and GIP.
Concessions for exploration and appraisal of unconventional gas (and other hydrocarbon resources) cover today large expanses of the country.
A comparison of the above concession map with the map of Poland's prospective shale basins, as assumed by PGI-NRI's report of 2012 for the purposes of recoverable resource assessment, reveals that the exploration area is much wider.
It includes but is not limited to:
- potential shale oil occurrence areas (eastern Poland's offshore economic zone of the Baltic Sea, the area bordering on Russia, eastern Masovia and the Lublin Region close to the border with Ukraine),
- areas wherein Lower Paleozoic formations probably fail to meet reservoir criteria, at least in light of available existing data (e.g. due to insufficient content and inadequate maturity of organic matter – PGI-NRI report of 2012, areas along both sides of the “golden” belt), and
- areas which have been little investigated so far for potential presence of unconventional gas accumulations (e.g. south and west Poland).
Accordingly, the map of concessions reflects the plans and expectations of those operators who have undertaken the risk of unconventional petroleum exploration. Only the results of exploration efforts will provide a clue to the prospectiveness of the areas under investigation.
author: Antoni Wójcicki