Secrets of shale rocks
Wieslawa Lewandowska
Apart from the USA and Canada Poland is the most active and most attractive place to find shale gas in the world. In Europe several countries have shale resources but Poland and France are evaluated as the most geologically attractive places. France might seem to be even more attractive than Poland but the ecological hysteria and sufficient nuclear energy make this country not intend to develop any shale industry. But Poland is eager to do it. Shale gas is our unexpected chance to have energy security, which is additionally connected with geopolitical comfort. That’s why we can hear praises: Poland has never had such a chance! Shale gas is Polish hope and reason of state!
Romantic story
A certain owner of a small oil company in Texas quietly conducted drilling for conventional gas in the 1980s. Drilling deeper and deeper he gained strange, accidental flows of gas from the strata in which he did not expect them at all. Gas was realised as if against the geological knowledge according to which shale rocks are only mother rocks that can produce gas at the most after a long geological process and temporarily they simply serve to seal, close the layers of gas we know.
George T. Mitchell, a man of passions, having the soul of a searcher and discoverer, decided to look at that mysterious flows of gas, sparing no expense. He intended to check why gas was flowing from those hard and compact rocks and at the same time he looked for some ways to increase that flow of gas. He organised a group of searchers that he financed for 18 years. The drillings were very expensive and not effective but they were not discouraging… One can say that thanks to some madness shale gas was documented. It was not a scientific work but only a fantasy of one man who did not fear losing money and wanted to check at all costs something what arose his curiosity. 18 years passed before he began his first commercial production of shale gas. In 2002 Mitchell sold his small firm to the big international company Devon for 3.5 billion dollars.
Underground broom and aureoles
Shale gas, called unconventional gas, has the same chemical content as the ordinary natural gas. Its ‘unconventionality’ concerns only the way it gathers in the depth of the earth and the way of its exploration, which is connected with the first feature. Conventional gas flows from the sandstone rocks and collects in smaller or bigger bodies-traps. Shale rocks are every compact, a kind of ‘petrified mud’ and that’s why gas, stored in its tiny natural pores, cannot move freely.
In 2002, in America the technology was used for the first time and until today it is identified with shale gas. It is the so-called fracking in horizontal boreholes, which enables effective gas exploration. The technology is that a vertical hole is drilled to a depth of 2-4 km and then it is continued horizontally to lateral lengths of even 1-3 km. Then using a strong water impulse under pressure to cause the formation to crack (as if someone broke a car window with a hammer) in several places on the whole length of the vertical crack. A net of fractures, going in every direction, through which gas flows freely is created in the hard rock. The amount of gas depends on the number of extra porous little channels that have been managed to be made in the rock.
The technology of shale gas exploitation is being developed. Recently only one borehole was drilled from one place on the surface and it collected gas at the depth of e.g., 1 km from the area of at least several hundred meters. Currently, on 2-3 hectare lots ca. 20 vertical drillings are made and from they horizontal drillings are made, which as if a broom diverges into all directions and at the depth of 2-3 km drains the layer, sweeping gas from the area of ca. 15 square km. Gas is freed by itself and through the fissures goes to special well bores in a horizontal pipe and then the process of production is continued like in the conventional technology.
Problem of water
Shale industry requires big amounts of water despite the fact that water is used only once in the whole technological process. It serves as a mechanical impulse, as ‘hydraulic hammer.’ Can we fear that the water balance in the areas of shale gas exploitation is disturbed? The calculations and various simulations of development of this industry in Poland state that the industry will need 4-10 times less water annually that Warsaw. The whole consumption of water in Poland amounts to only 11 % of the available reserves. There are regions where water is a real problem but that does not concern the regions of the potential exploitation of shale gas. In this case it will be essential to control the tempo of water drawing because pumping too intensively, at every place; even the one supplying most water, the water balance can be disturbed. In order not to have local drained places precise regulations limiting the tempo of water consumption must be created in Poland.
Ecological threats and burdens
Ecologists warn that several hundred chemical substances are used in the shale gas industry whereas the drilling companies refute this argument stating that actually in particular cases only several chemical substances, chosen from a wide rage, are used. The chemicals must be added to water pumped with sand to the pipes to achieve proper technological effects. The representatives of the shale gas industry assure that most of these substances are used in everyday life, in the construction, cosmetic, pharmacological and even food industries. Under the pressure of ecologists the producers stopped using the cancerous Diesel fuels (they were added to water to decrease friction and increase the effect of ‘hydraulic hammer’). The producers claim that the possibility of the contamination of subsoil waters is extremely very small. Since the gas formations are at the depth of 3-4 km and drinking waters are at the depth of 100-200 m below earth surface and thus they are separated by a 2-3 km isolation layer from the area of gas exploitation. Danger can appear only in cases of damages, e.g., badly drilled holes, bad quality pipes, badly secured pipe with a cement ‘coat’ – a leak can appear. However, small leaks are more likely to happen on the surface than deep down. The ecological (as well as economic) disadvantages of the shale gas industry is that more drillings must be made than in the conventional technology, which causes bigger disturbances on the surface, a temporary disorganisation of the life of the local communities and some damages in the landscape. Noise can be a problem, too (especially during the process of cracking) and there is the noise caused by heavy machines. But all these inconveniences last several months at the most and then after the burdensome neighbours there is – as producers assure – only a re-cultivated area with gas holes that could be contained in a small building. The comforting thing is that shale gas, contrary to natural gas, goes to the surface under small pressure and thus there are no threats of dangerous explosions. In classical layers such explosions happen fairly often and can be spectacular like the one in the Mexican Gulf.
Polish scenario for next years
Since 2007 there are search works in Poland, conducted at first by two companies and currently by several dozen firms, mainly American and Canadian ones. The drilling activities will be centred in central Pomorze, eastern Mazowsze and the eastern region of Lublin. In the next 2-3 years about 120-150 search holes will be drilled (at present there are 7 and two are being made). The first drillings have confirmed the presence of shale gas to a satisfying extent. In 2-3 years in these areas the firms will try to begin the exploitation phase. They will need concessions from the state administration and the permission of the local community. But before the first concession for shale gas exploration are awarded proper legal regulations (tax, ecological, hydrological and others) should be created because the present ones are far from being sufficient. The organ to grant concessions for natural resource exploitation in Poland is the Ministry of Environment. It evaluates the results of search works of companies, prepares contracts of exploitation concessions that must have clearly specified financial conditions. In the case of the shale gas industry, which is connected with certain fears that it can destroy landscape, the important thing is that the Polish public administration approves the so-called plan of deposit management, describing in detail the extractive activities and the way to limit inconveniences. Extractive companies must receive the permission of the local community in the territory of which they intend to work. They should present their plans, needs and conditions of collaboration to the local community. The community can refuse granting its permission and it will certainly happen in the typically tourist regions. For the poor agricultural communities – a common consent is in such cases – ‘shales’ can be chances for development and getting rid of poverty. And the majority of the Polish ‘shale zones’ are exactly such areas.
Currently, one cannot make optimistic presumptions that shale industry will have no negative effect on the environment and people’s lives but, as the specialists claim, the advantages will be much bigger than the potential inconveniences, of course provided that the Polish interests will be reasonably cared for, without neglecting the interests of solid extractive companies so that they do not withdraw their activities from Poland.
"Niedziela" 27/2011