Time filter

Source Type

News Article | March 4, 2016
Site: www.nature.com

Large petroleum pumps nodded up and down in the background as British Prime Minister David Cameron donned a blue industrial jumpsuit to promote a controversial drilling technique known as hydraulic fracturing, or fracking. In his 2014 visit to a potential drill site in eastern England, Cameron laid out the benefits of tapping Britain's shale formations to release valuable natural gas. “We're going all out for shale,” he said. “It will mean more jobs and opportunities for people, and economic security for our country.” Cameron hopes to replicate the surge in natural-gas production that has happened in the United States thanks to fracking — which involves injecting fluids into shale to liberate locked-up hydrocarbon deposits. The fracking revolution helped to revitalize the US economy, and Cameron's Conservative Party seeks to spark a similar gas boom in the United Kingdom. In August last year, his newly elected government offered drilling licences for shale deposits and it touted estimates that “investment in shale could reach £33 billion [US$46 billion] and support 64,000 jobs”. Over the past few years, fracking fever has swept through several European nations, including Denmark, Lithuania, Romania and especially Poland, which has seen more shale exploration than any other nation on the continent. Fracking might help to boost gas production in Europe at a time when it is facing a sharp decline. Older gas fields in the North Sea are running out, as are deposits in Germany, Italy and Romania. The disappointing output has increased Europe's dependence on imported gas, mainly from Russia. European leaders have grown wary of relying on that source, especially after diplomatic relations chilled when Russia invaded Ukraine in 2014. But Europe's appetite for gas could increase as it tries to cut greenhouse-gas emissions — which will probably require reducing coal consumption (see 'Looming gas crunch?'). The European Commission says that “gas will be critical for the transformation of the energy system”. This means that countries such as the United Kingdom have invested an immense amount of hope in shale gas. But a close examination of the industry suggests that any fracking boom in Europe is a long way off — and some experts say that it may never arrive. Despite several years of exploratory drilling, there are currently no commercial shale-gas wells in Europe. Tests of the region's shale potential have been limited, and the results so far have been generally disappointing, say geologists and energy experts. It remains highly uncertain how much gas would be recoverable with today's technologies, and even more difficult to forecast how much would be profitable to extract. All that leads to big questions about Europe's shale hopes, says Jonathan Stern, a natural-gas expert at the Oxford Institute for Energy Studies in Oxford, UK. “There has been an enormous amount of ridiculous hype about shale gas in Europe.” A decade ago, the United States was facing a similarly dismal outlook for natural gas. Production from conventional fields was petering out, and geologists did not expect that alternative sources of gas could compensate for the shortfall. But within a few years, the picture suddenly brightened owing to improved drilling and fracking technologies, which tapped previously inaccessible gas reserves and unleashed a boom dubbed the shale revolution. Shale is almost impermeable to oil and gas, so companies must fracture the rock to liberate those hydrocarbons. The idea that a similar wealth of untapped energy could be lurking in the rocks below Europe is economically appealing. But geologists know relatively little about the potential of shale-rock formations in Europe because there has been less onshore drilling than in the United States. European companies have sometimes drilled through shale to reach other rock formations, but they have rarely taken detailed measurements or collected samples of the shale layers. So far, Poland's shale formations have attracted the most attention within the region. The nation depends heavily on coal, and what natural gas it does use comes almost exclusively from Russia. In the mid-2000s, the burgeoning US shale boom prompted Poland's government to offer shale exploration licences that went to local companies as well as major international energy firms, including the US companies ExxonMobil and Chevron, and the French firm Total. Poland's foreign minister, Radosław Sikorski, said in 2010 that Poland would become “a second Norway” — referring to Europe's second-largest natural-gas producer, after Russia. The excitement was bolstered in 2011 by an assessment from Advanced Resources International (ARI), a consultancy in Washington DC that was commissioned by the US Department of Energy to study shale-gas resources worldwide. That study estimated the quantity of shale rock and other parameters such as the total organic content of the rock, which is the source of oil and gas. ARI also estimated parameters to represent the risk that some shale zones, or plays, might not prove promising or that only a portion of them might be amenable to drilling. Given these assumptions, ARI calculated that Poland's shale-gas plays hold about 5,295 billion cubic metres (bcm) of technically recoverable gas, the most shale gas of any nation in Europe. If all of that gas could be extracted, it would be equivalent to 325 years of Poland's current gas consumption1. While companies began drilling dozens of test wells in Poland, the Polish Geological Institute (PGI) in Warsaw made its own estimate in March 2012. Taking the considerable uncertainty over the data into account, the PGI calculated that Poland has 346–768 bcm of recoverable shale gas onshore — about one-tenth of ARI's figure2. Then in July 2012, the US Geological Survey (USGS) released another study of Poland's shale-gas resources. The agency assumed that individual wells would yield about half as much gas as the PGI assumed and that the area that is likely to contain recoverable gas is only about one-third of the size. So the USGS wound up with an estimate even smaller than the other two, with a mean result of just 38 bcm of recoverable gas, and a huge range of uncertainty, from 0 to 116 bcm. The mean was about one-tenth that of the PGI's estimate, and about one-hundredth of ARI's3. “One report — huge potential. A year later — nothing,” says PGI geologist Hubert Kiersnowski. “The scale of uncertainty is so big.” Meanwhile, results started coming in from test wells. Of the 72 wells drilled by the end of 2015, 25 were successfully fracked to release gas. However, these wells yielded only about one-third to one-tenth of the flow that would be required to turn a profit, says petroleum geologist Paweł Poprawa of AGH University of Science and Technology in Krakow, Poland, and formerly of the PGI. None of the wells has become a commercial producer. At the peak of interest in early 2013, companies held shale-drilling licences covering about one-third of Poland. But throughout 2013 and 2014, the major international energy firms gave up their shale-exploration licences and left the country, often citing disappointing results. The last to leave was Texas-based ConocoPhillips in June 2015 — now Poland's shale drilling is almost at a standstill. One major hurdle to development is that Poland's shale is expensive to drill because it is buried around 3–5 kilometres down, compared with around 1–2 kilometres for most successful US plays. Some of Poland's shale also has a high clay content, which makes the rock harder to fracture. And exploratory holes into one of Poland's most promising shale formations — in the north, near the Baltic Sea — showed that it held a geological barrier that would limit how much gas could be tapped by individual wells, says Poprawa. The drilling results suggest that ARI “overestimated the acreage, the thickness, and the quality of the shale”, he says. The PGI says that its previous lower estimates are reinforced by its latest, as-yet-unpublished assessment, which draws on recent shale-drilling tests. PGI spokesperson Andrzej Rudnicki calls ARI's much higher estimates “enthusiastic, but geologically unrealistic”. “The results in Poland to date indeed have been disappointing,” concedes geologist Scott Stevens of ARI. He says that the main reason for the unproductive wells was “extremely high” stresses in the rock, which makes fracking less effective. “There was no way that the exploration companies could know that in advance,” he notes. Nonetheless, he argues, “It is too soon to dismiss Poland's extensive shale potential.” Given the limited available data, he does not see a reason to revise ARI's estimate. Even the PGI's lower estimates suggest that there is a still a substantial amount of gas trapped in Poland's shale. However, it is uncertain whether any of that gas will be profitable to extract. “I am still hopeful,” Poprawa says. “But the initial hopes were not realistic.” Although companies raced to grab concessions in Poland, activity in the United Kingdom has been subdued. In 2011, Cuadrilla Resources fracked the United Kingdom's first shale well near Blackpool in northern England, but this triggered two small earthquakes, which led the government to place a year-long moratorium on further fracking. After the moratorium lifted, companies slowly began vying to tap UK shale. According to a 2013 assessment by ARI, UK shale holds 17,600 bcm of gas. Only 728 bcm of this is judged to be technically recoverable: if that could be profitably extracted, it would satisfy the United Kingdom's gas needs for about a decade4. The British Geological Survey (BGS) has assessed the shale-gas resources in the United Kingdom's three major plays by constructing a 3D model of the subsurface using drilling records and seismic surveys, which has allowed it to roughly estimate the volume of shale rock. But geologist Ian Andrews of the BGS insists that this estimate is just a first pass based on the seismic information available, “which is sparse, and fairly poor”. By testing old rock cores stored by the government, the BGS was also able to measure some of the properties of UK shale, such as the total organic carbon (TOC) content. Successful shale plays in the United States typically have TOC values greater than 2%. Although TOC measurements for the United Kingdom are scant, the available data suggest that there are large volumes of rock above the 2% threshold. But data are lacking for other key parameters, such as the rock porosity, which adds greatly to the uncertainty of these projections. The BGS estimated that the three shale plays it has assessed so far hold around 39,900 bcm of gas, with an uncertainty range of 24,700–68,400 bcm (refs 5,6). This is more than the ARI estimate, but that study only considered the most promising rock. The BGS did not attempt to estimate how much of that gas would be technically recoverable. “How much we can get out of the ground, I don't think anybody knows yet, because the drilling hasn't happened to test it,” says Andrews. Although the BGS's studies used US shale plays as analogues for crucial parameters, the two nations have different geological histories. The United States has large deposits of shale that are not too thick and have been folded little over time. The shale in the United Kingdom is more complicated, says petroleum geoscientist Andrew Aplin of the University of Durham, UK. “It's been screwed around with more”, creating more folds and faults. That greater complexity could pose challenges. One risk is that pumping fluid into rock can trigger earthquakes if the wells are near faults or large natural fractures. “It's better to stay away from them, especially when they're located near densely populated areas,” says natural-gas expert Rene Peters of the Netherlands Organisation for Applied Scientific Research (TNO) in the Hague. But there has been relatively little high-resolution seismic imaging in Europe, he says, so “not all these fractures are known”. Small faults can pose another challenge. If the fracking fluid leaks into a fault, the pressure on the rock is reduced and the fracking is less effective. Given the geological hurdles and the United Kingdom's dense population, it may prove difficult to find many promising, acceptable places to drill. The United Kingdom's appetite for gas is expected to grow sharply. In November, the government set out the goal of phasing out coal-fired power plants by 2025, unless they have carbon capture and storage systems. The government expects nuclear, wind and solar power to play a part in filling the void left by coal — but natural gas would be the linchpin because it produces less carbon dioxide and other pollution than does coal, and existing infrastructure can be used to produce electricity from gas. “We'll only proceed if we're confident that the shift to new gas can be achieved within these timescales,” UK energy secretary Amber Rudd said in a speech announcing the policy shift. “We currently import around half of our gas needs, but by 2030 that could be as high as 75%. That's why we're encouraging investment in our shale-gas exploration so we can add new sources of home-grown supply.” Other European nations are also counting on natural gas to help them to cut their coal use and meet their commitments under the United Nations climate treaty signed in Paris in December. But shale gas may not provide the answer. At the June 2015 World Gas Conference in Paris, industry speakers were pessimistic that Europe would see a fracking boom like that in the United States. Philippe Charlez, manager of unconventional resources development at Total, said that given the current costs for shale wells, “we are very, very far in Europe from profitability”. Many assessments in the past two years — including those by the International Energy Agency and oil giants BP and ExxonMobil — agree that Europe is unlikely to produce much shale gas, and that conventional gas production will continue to decline7, 8, 9. And if gas imports cannot make up the difference, says Stern, “Europe is going to have even more difficulty reducing carbon emissions”. The most recent signs are not good for shale across the continent. Besides retreating from Poland, major petroleum companies have pulled out of nascent shale drilling efforts in Romania, Lithuania and Denmark, usually citing disappointing yields. Various members of the European Union from Bulgaria to France have instituted moratoria or bans on fracking, as have Scotland, Wales and Northern Ireland, all citing environmental concerns. England is home to some of the few remaining attempts to tap shale gas in Europe. A handful of companies have applied for permission to drill, which could finally reveal whether the United Kingdom's shale deposits will be a jackpot or a dud. But environmentalists have put up a strong fight, and permissions have been slow to emerge. Cuadrilla requested approval in January 2015 to drill beneath the undulating fields of Lancashire, but the county council rejected the request in June over concerns about traffic, noise and the visual impact of drilling. That decision and the broader difficulties that confront fracking in Europe leave the future of natural gas there in limbo. To figure out whether any play has potential, companies must drill as many as 50 to 100 wells. But the public opposition and the poor drilling results so far mean that companies are not eager to sink that kind of effort into fracking in Europe right now, says Stern. “I can't see any country, including the UK, where that will happen anytime soon.”

Marks L.,University of Warsaw | Marks L.,Polish Geological Institute
Quaternary Science Reviews | Year: 2012

The Lower Vistula Region in northern Poland is a stratotype area for the Vistulian (Weichselian) glaciation and during Last Glacial Maximum (LGM) the southernmost extension of the Scandinavian ice sheet occurred in western Poland and in eastern Germany. Reinterpretation of the available geochronological data (radiocarbon, 36Cl and 10Be ages), supplied with new field geological evidence, mostly for the Late Vistulian ice sheet limits and movement directions, was focused in three key regions in Poland. During the late Middle Vistulian there was one or two ice sheet advances in the Lower Vistula region. The Late Vistulian maximum ice sheet limit in Poland was time-transgressive and occurred at 24-19 kyrs BP (generally, the younger to the east). Ice sheet limits during the Leszno Phase occurred at 24 cal/ 10Be/ 36Cl kyrs, the Poznań Phase ice sheet limit was dated to 19 10Be/ 36Cl kyrs and the Pomeranian Phase ice sheet limit about 16-17 10Be/ 36Cl kyrs. Every Late Vistulian glacial phase in Poland was preceded by an ice sheet retreat. © 2010 Elsevier Ltd.

Hesselbo S.P.,University of Oxford | Pienkowski G.,Polish Geological Institute
Earth and Planetary Science Letters | Year: 2011

During the Mesozoic (250-64. Ma) intervals of about 0.5. Myr were subject to severe environmental changes, including high sea-surface temperature and very low oxygen content of marine water. These Oceanic Anoxic Events, or OAEs, occurred simultaneously with profound disturbance to the carbon cycle. The carbon-isotope anomaly in the Early Jurassic that marks the Toarcian Oceanic Anoxic Event (T-OAE) at ~. 182. Ma is characterized in marine sections by a series of dramatic steps towards lighter values. Herein we present new carbon-isotope data from terrestrial organic matter (phytoclast separates), collected through a Late Pliensbachian-Middle Toarcian coastal and marginal marine succession in the Polish Basin, a setting where hinterland climate and sea-level change are well recorded. The results show that the shift to light carbon-isotope values in the woody organic matter, and therefore also in atmospheric carbon dioxide, similarly occurred in major steps. The steps are here correlated with those identified from marine organic matter, where they have previously been attributed to 100. kyr eccentricity forcing of climate. The results provide strong support for orbitally and climatically controlled release of isotopically light carbon from gas hydrates into the ocean-atmosphere system in a series of rapid bursts. Additionally, a link between the carbon-isotope steps and shoreline movements can be demonstrated. Individual peaks of the negative excursion are mostly associated with facies indicative of sea-level rise (flooding surfaces). However, at the same time inferred higher atmospheric carbon-dioxide content may be expected to have resulted in increased rainfall and temperature, leading to accelerated weathering and erosion, and consequently increased sediment supply, progradation and regression, causing some mismatches between isotope shifts and inferred sea-level changes. Enhanced abundance of megaspores derived from hydrophilic plant groups, and marked increase in kaolinite, are coincident with the overall development of the negative isotope excursion. The combined data suggest that each 100-kyr cycle in carbon-isotope values was characterized by increasingly severe palaeoclimatic change, culminating in extremely hot and humid conditions co-incident with the peak of the final most negative carbon-isotope excursion. The chemostratigraphic correlation allows very precise dating of the Late Pliensbachian-Middle Toarcian coastal and marginal marine sedimentary succession in the Polish Basin. © 2010 Elsevier B.V.

Leszczynski K.,Polish Geological Institute
Geological Quarterly | Year: 2012

The paper presents a set of maps illustrating the internal geometry of the Upper Cretaceous-Danian sedimentary sequence in the Polish Lowlands. Qualitative lithofacies are used for reconstructions with the dominant lithofacies component and accessory components indicated. The following maps are produced: (1) base Upper Cretaceous structural map; (2) Upper Cretaceous (including Danian) thickness map; (3) thickness map of succession K3 (Cenomanian-lower Turonian, excluding the upper Albian cycle K3-I, which is the lowermost cycle of succession K3, but formally belongs to the Lower Cretaceous); (4) succession K4 (upper Turonian-Danian) thickness map. The maps of successions K3 and K4 illustrate the post-inversion geometry of the basin for the pre-inversion (Cenomanian-lower Turonian) and syn-inversion (upper Turonian-Danian) successions. Thickness analysis shows an increasing difference in subsidence rate during the Late Cretaceous between the areas extending on the two sides of the present-day Mid-Polish Swell. Much higher subsidence rates during deposition of succession K4 occurred in the area extending to the SW of the swell. The maximum subsidence zone migrated with time from the Pomeranian and Kujavian segments towards the Kujavian and Lublin segments. The lithofacies pattern is presented in seven maps constructed for individual eustatically and tectonically controlled cycles: K3-II-K3-III (early Cenomanian-early late Cenomanian), K3-IV (latest Cenomanian-early Turonian), K4-I (late Turonian-Coniacian), K4-II (Santonian-earliest Campanian), K4-III (late early Campanian-earliest Maastrichtian), K4-IV-K4-V (late early Maastrichtian-late Maastrichtian) and Pc-I (Danian-?ear-liest Selandian).

Krzywiec P.,Polish Geological Institute
Geological Society Special Publication | Year: 2012

The Permian-Cretaceous Polish Basin belonged to the system of epicontinental depositional basins of Western and central Europe and was filled with several kilometres of siliciclastics, carbonates, and also thick Zechstein (approximately Upper Permian) evaporites. Its axial part (the so-called Mid-Polish Trough) characterized by the thickest Permo-Mesozoic sedimentary cover, developed above the Teisseyre-Tornquist Zone, lithospheric-scale boundary separating the East European Craton and the Palaeozoic Platform. The Polish Basin was inverted in Late Cretaceous- Paleocene times. A synthesis of studies based on seismic reflection data allowed some general rules regarding salt tectonics of the Polish Basin to be formulated. Two general classes of structures genetically related to the presence of the Zechstein evaporites have been described: peripheral structures located within NE and SW flanks of the Polish Basin, outside its axial part and structures located within its axial part. The first class of structures includes grabens bounded by listric faults detached above salt or salt pillows that developed where Zechstein evaporites were of relatively smaller thickness and where sub-Zechstein fault tectonics played a relatively smaller role. The second class of structures includes more mature salt structures such as salt pillows and salt diapirs and is related to the more axial part of the basin, characterized by relatively thicker Zechstein evaporites and by more intense basement tectonics. First salt movements (salt pillowing) took place in the Early Triassic that in certain cases was followed by the Late Triassic salt diapirism and extrusion. In Jurassic-Early Cretaceous times, no significant growth of salt structures took place. Most of the salt diapirs have been finally shaped by the Late Cretaceous inversion tectonics. Some salt diapirs also underwent Cenozoic reactivation, associated with localized Oligocene or Miocene subsidence that in some cases was followed by younger (Pliocene-Quaternary) inversion and uplift. © The Geological Society of London 2012.

Neotectonic stage stress and strain evolution was analyzed along a vertical lithospheric profile crossing the Dinarides, Pannonian Basin, Carpathians and East European Craton. A structural and lithological model was constructed based on distribution of seismic wave velocity along the Cel05 deep seismic sounding line. Rheological properties of each lithospheric layer were calculated as an average value for component rocks. In the applied model a highly laterally heterogeneous section of the lithosphere underwent 2.5% of shortening during 7.5. Myr, which corresponds to neotectonic inversion of the Pannonian-Carpathian-Dinaric region. The coupled viscoelastoplastic model predicts stress regime changes, within mechanically partitioned lithosphere, that together with complex rheological properties controls the deformation pattern. Long-wavelength lithospheric buckling was initiated during the first stage of inversion. It was followed by development of short wavelength minor folding in the detached upper crust. The topographic surface within the basin and over the transition to adjacent tectonic units was modified by buckling and swelling mechanisms producing folds of 800. m amplitude. Buckling, more efficient in the initial stage of inversion, was over time substituted by crustal swelling that contribute to raising anticlines at the topographic surface due to isostatic compensation. Compound mechanism of folding causes migration of anticlines at the topographic surface and synclines at Moho, which finally produces gentle pinch-and-swell pattern in the crust. Efficient mechanism of continental lithosphere buckling was described under minor shortening and a low stress level. © 2011 Elsevier B.V.

The faunal dynamics of benthic foraminifera in the Middle Jurassic ore-bearing clays of Gnaszyn (Kraków-Cze{ogonek}stochowa Upland, south-central Poland) are used to reconstruct sedimentary environments. Two types of foraminiferal assemblages, distinct in their quantitative and qualitative composition, were distinguished; type I assemblages, characterizing intervals between horizons with sideritic concretions; and type II assemblages, characterising horizons with sideritic concretions. Benthic foraminifers were further subdivided into eight ecological morphogroups, based on their morphological features and micro-habitats. Type I assemblages consist mostly of plano/concavo-convex, small-sized epifaunal morphotypes, with a restricted occurrence of shallow infaunal forms and a scarcity of deep infaunal taxa, which suggests low-oxygen conditions in both sediment and bottom waters, and a high sedimentation rate in an outer shelf environment. Type II assemblages are characterized by high taxonomic diversity, high specimen abundance and variability of epifaunal and infaunal morphotypes representing a mixed group of specialized feeding strategies. This suggests optimum living conditions controlled by a lower sedimentation rate, relatively well-oxygenated bottom waters and sufficient or high food supply.

Kiersnowski H.,Polish Geological Institute
Geological Society Special Publication | Year: 2013

study of a Permian aeolian depositional system in the Polish Upper Rotliegend Basin (PURB) is described and is placed in the wider context of similar studies of the German, Dutch and UK parts of the Southern Permian Basin (SPB). Aeolian complexes in the PURB consist of several stacked erg units inter-bedded with fluvial and playa deposits. These deposits are grouped into seven main units: six predominantly aeolian and one fluvial. The separate aeolian units were considered as representative of the changing pattern of palaeowinds directions. The correlations of wind mean directions assisted in the development of a new depositional model for part of the Eastern Erg aeolian complex within the PURB. © The Geological Society of London 2013.

Branski P.,Polish Geological Institute
Geological Quarterly | Year: 2010

In lower Toarcian clay deposits (Ciechocinek Fm., VIII depositional sequence of the Lower Jurassic) from three boreholes from the Polish Basin, illite-dominated sedimentation representing the lower part of studied interval was interrupted by enhanced kaolinite input. Levels of high kaolinite/illite ratio at the VIIIb/VIIIc parasequence boundary suggest strong continental weathering in a humid-subtropical to tropical climate related to the phase of the early Toarcian global warming recorded at the top of the tenuicostatum Zone and correlated with isotope curves from a number of European sections. Kaolinite enrichment may be locally enhanced by reworking of pre-Jurassic kaolinitic rocks and differential settling. Diagenetic processes were not sufficient enough to transform the initial kaolinite, but may have altered smectite and mixed-layers into illite and/or chlorite.

Pokorski J.,Polish Geological Institute
Geological Quarterly | Year: 2010

The present-day structural pattern of the Baltic Depression developed due to superimposition of three main deformation phases: Syn-Cal-edonian (after the Silurian), syn-Variscan (at the end of Carboniferous and beginning of Permian) and syn-Alpine (latest Mesozoic or earliest Cenozoic). The major restructuring of the area occurred as a result of syn-Variscan deformation that took place in latest Carbonif-erous and earliest Permian times. Most of the faults developed or became reactivated probably at that time. Syn-Alpine deformation man-ifested itself relatively weakly, mainly by reactivation of some pre-existing faults.

Loading Polish Geological Institute collaborators
Loading Polish Geological Institute collaborators