Polish Shales: Knowns, Unknowns, etc.

Polish geologist suggests what drillers should know

International hydrocarbons drillers, service providers and numerous others looking to cash in on Poland’s shale basins gathered at Shale Gas Results in Europe 2011 in Warsaw, Poland to hear about the latest developments in the efforts to explore and produce natural gas there.

Piotr Krzywiec, Associate Professor at the Polish Geological Institute was one of the first speakers to fill them in on what’s been happening. His talk to delegates was entitled The Lower Paleozoic Shales of the East European Craton in Poland: what we know, what we don’t know and what we should know (a regional seismic perspective).

Krzywiec revealed his motivation for assembling such information, explaining “We’ve spent a couple of busy months putting together a proposal for a regional seismic project, which would cover the whole Silurian basin and is set to start in October. We wanted to summarize what was known.

“Researchers rarely go on stage to talk about what they don’t know. Quite a lot is still unknown,” he admitted.

Regarding the current status of exploration he showed an area of red in the Silurian basin and made a yellow overlay, which fit well as he slide it over to another part of Europe. “This is almost equivalent to the North Sea – we understand the time, effort and money that it took to understand the North Sea basin. We knew enough to start these exploration efforts, but we have a long way to go in understanding the evolution of these shale gas plays,” said Krzywiec.

Then overlaid his yellow patch onto shale basins in North America to show it was of comparable size.

Showing a map with the east European craton, Krzywiec said: “Most of you would agree that most of the area would fall into this area. This zone is very deeply rooted, goes to lower crust layers and this is why we have all of these shales on top of this.”

A magnetic map showed that the concessions sat on the cratonic edge in Poland.

Krzywiec offered 2D seismic reflection data, saying a lot of it was outside the Silurian basin. “We have much more data in the Lublin basin and some in the Baltic basin, but there are huge gaps.”

He continued, “There are loads of wells in this area from the 50s, 60s and 70s – they are deep research wells drilled to study the rocks. We have loads of data and kilometers of core still available and which we have used to calibrate all sorts of geophysical data, but there are huge gaps and we don’t know what’s going on between those rocks.”

A map of high potential and low/uncertain potential was presented.

“Poland is covered by numerous high quality deep refraction/wire angle reflection profiles that provide crucial information on crustal lithospheric structure but lack resolution at shallow depths necessary for exploration-focused studies,” he explained.

Then it was time to move on to “What we don’t know” according to Krzywiec, who offered data coverage gaps from existing wells and 2D seismic.

He said, “Whatever we draw and extrapolate from data – we need more data to remove those question marks.”

According to him, the Baltic and Lublin basins were just sub basins of the Silurian basin.

“Let me start with Lublin area – there are different models out there based on significant data. This is a really basic question how this area evolved and concerns potential of this whole area; existing data cannot address those questions.”

Krzywiec’s presentation showed some very poor seismic imaging of the Lower Paleozoic succession (from 1975). “This was one of those deep research wells and what you can see is a fairly large amount of information above, but nothing below.”

But there was better structural seismic imaging of the Lower Paleozoic, he said,  because of new seismic shot in 2003. Krzywiec noted that the data resolution was still not high enough for stratigraphic interpretation, among others.

Krzywiec said: “Negative impacts include the difficulty identifying the best concessions (new, farm-in), structural dangers, difficulty placing wells in best potential areas, difficulty staying in the zone, etc.

“We need to understand regional evolution of the entire basin, stresses, and facies changes, which are all crucial for understanding it.”

As for “what we should know” Krzywiec listed the thickness of the shales, distribution, tectonic evolution and structural complexity.

He remarked, “We know a lot, enough for companies to come to Poland and start exploration. We had a good start with these existing wells, but it’s far from being the end of the road.”

Krzywiec concluded: “We need to understand loads of issues and need to avoid the U.S. model: ‘drill and see what’s down there.’”