Polish shales appear to be less energy-rich than their American counterparts, Richard E. Lewis of the service company Schlumberger revealed during the Shale Science conference in Warsaw, yesterday.
The data from the Syczyn and Berejow wells in Poland’s Lublin province showed total organic content (TOC) of 1.5-2 per cent, compared to 3.3-3.6 per cent in the American Marcellus and Barnett formations. The total organic content is the total amount of organic material present in the rock, expressed as a percentage by weight. Generally, the higher the total organic content, the better the potential for hydrocarbon generation. A TOC of 2 per cent is considered the minimum to warrant exploration.
Another potential problem with the Lublin shales is their low porosity and permeability, as well as the presence of clay deposits which diminish the effectiveness of hydraulic fracturing by clogging up the fissures.
The advantage of Lublin shales, on the other hand, is the thickness of the layer, which reaches up to 75 meters. Richard E. Lewis said that in terms of thickness, Lublin shale is second only to Vaca Muerta formations in Argentina.
This simplifies the exploration process as there is no need to drill the wells horizontally. Hydraulically stimulated vertical wells should be sufficient to extract the resources.
The total gas content in the drilled plays is of about 1.1 billion cubic meters per square kilometre. By comparison, in the U.S. this ratio reaches 2 billion cubic meters per square kilometre.
The good news is that the Berejow well showed the presence of crude oil and natural gas liquids, which are more economically valuable than dry gas.
There are reasons to believe that the shale formations in Pomerania, in the north of Poland, might be more promising. According to Pawel Poprawa, an expert from the Institute of Energy Studies, the highest rate of TOC is likely to be present in the basins in Central Poland and Pomerania. Unfortunately, due to the depth of these deposits they are still very poorly understood and it is difficult to determine the correct rate of TOC.
However, at only 40 metres’ thickness the Pomeranian shales are much thinner than those in Lublin and their unique structure might not yield them to hydraulic fracturing.
Adapted from GazLupkowy.pl
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