No. 1, 2006
Prof. Yevgeny Panfilov
Dr. Sc. (Techn.)
TO MAINTAIN A SUBTLE BALANCE
Oil and gas companies must reckon with the important factors of geoecological safety of the subsoil and mineral development
A lot of attention is given today to the problem of environmental pollution. Major oil and gas companies develop and implement environmental programs and strategies and allocate enormous funds to environmental protection. But most environmental interventions focus on minimizing adverse impacts on soil, water, and air. At the same time, such a topical problem as geoecological safety of the subsoil and mineral development operations has been largely disregarded by international corporations.
Mysteries of the Blue Planet
Planet Earth is a constantly developing highly-organized system of interlinked components, extremely energy-saturated from the core to the mantle. The planet is a product of the Cosmos and constantly exchanges energy with the Cosmos, since it has to “discharge” accumulated energy in a variety of ways (through earthquakes, volcanic eruptions, tsunamis, cyclones, tornadoes, etc.), especially in areas of high technogenic stress.
One of the greatest dangers to humanity comes from processes that develop within the Earth. Man's intrusion into the planet's subsoil, mainly for the purposes of extracting minerals and using underground voids, causes the subsoil to respond in ways that are difficult or impossible to predict. The subsoil responds in a variety of forms. Technogenic earthquakes are correctly considered to be the most significant of those. According to specialists, over 70 technogenic earthquakes with magnitudes of 4.5-5.0 points on the Richter scale have occurred around the world in the past 30 years.
Other threats to humanity include such geological phenomena as land subsidence over mines and pits, changes in land topography, cave-ins, landslides, rock bumps, dust and gas releases in mines, as well as physical, and chemical-bacteriological contamination of land, subsoil, and water. In addition, considering the increasing influence of biogeochemical, geopathogenic, and radiation areas, one will realize that the subsoil's “behavior” is one of the principal factors that determine the condition of the natural environment and drive human activity on the planet today.
Researchers differentiate among the concepts of the cosmoecological safety of the planet, the geoecological safety of the planet's subsoil, which is conditioned by natural processes in the subsoil, and the ecological safety of mineral development. The consequences of the ecological safety of the first two types can only be studied and, perhaps, predicted, but the effects of the ecological safety of mineral development operations can be managed and prevented, based on an understanding of technogenic impacts. It is difficult, however, to differentiate between man-made and natural adverse phenomena and processes, therefore ecological safety of the subsoil and ecological safety of mineral development operations must be managed in an integrated manner.
One possible solution to the tasks of ecological safety of the subsoil and mineral development would be to set up a system for monitoring the geological and other environments and technogenic impacts on those environments. Such lithological monitoring would involve zoning, mapping, and modeling of near-surface and subsoil parts of the planet and specific sites thereof.
In terms of general understanding of the scope and magnitude of the global changes in the Earth and in its subsoil, crustal plates can be viewed as basic lithosperic blocks (BLBs). In turn, BLBs consist of elementary lithospheric blocks (ELBs). Such classification has to do with the fact that most mineral development operations affect subsoil areas that are much smaller in size than BLBs: a few square kilometers in area and 3-4 km in depth (mines and pits) to 12-13 km in depth (exploration wells).
It is difficult to identify ELBs' parameters or to measure their environmental capacity, because humanity society today is so far unable to perform a detailed geoecological study of the subsoil of the entire planet. In most instances, ELBs' prioritization focuses on priority exploration and prospecting areas. The nature of prospecting and exploration works does not always match the definition and evaluation of the environmental capacity of the subsoil block being explored. Therefore, no mineral development project is adequate if it is not based on information about the geological environment's maximum capacity for absorbing technogenic impacts.
Production needs care
Based on the general understanding of processes and requirements concerning ecological safety of mineral development, it is advisable to specify those requirements vis-à-vis specific mineral resources.
Open-cast mining of solid minerals is used very widely around the world today. Quarrying is considered to be the most hazardous mineral production method environmentally, for it involves technogenic impacts of every type: landscape distortion, disturbance of the underground water pressure regime, modification of the chemical composition of underground waters, contamination of air, soil, wildlife, vegetation, and water bodies with dust and gasses, as well as rock mass stress redistribution.
Subsoil development of minerals is generally safer ecologically than quarrying. The key benefits of subsoil mining methods include shifting of mineral extraction processes from the surface underground and the use of closed-cycle production processes, which sharply reduce adverse environmental impacts. But contact with aquifers strongly increases the risk of contamination of the geological and hydrogeological environments (especially chemical and physical-chemical contamination).
It should be pointed out that, as oil and gas are recovered, rock mass stress is redistributed in the subsoil, and this may lead to unpredictable adverse consequences. A number of studies by Russian geophysicists demonstrate, for example, that intensive and environmentally thoughtless development of oil fields in Western Siberia will lead to a subsidence of the Earth crust by 2-3 mm a year. This is also illustrated by actual data obtained in other countries – the United States, Norway, Venezuela, and Azerbaijan. Since the Western-Siberian Lowland is located below sea level, the subsidence may cause changes of a truly global scale: the lowland may be flooded by the Arctic Ocean, which will entail tremendous consequences for the entire world.
Another adverse impact on the subsoil is resulted from ill-considered use of various oil recovery enhancement methods. Some of them may lead to chemicals leaking into rock formations, which would contaminate other mineral resources, including underground waters. Besides, using modern recovery enhancement techniques one must take into account potential impacts on other minerals produced in the same area. In the Perm Region, for instance, oil fields are located close to potassium salt; in Yakutia, oil is deposited close to diamonds.
Another problem that typically accompanies oil field development and use is oil spills from damaged ships or ruptured pipelines, or caused by wells' blowouts or other accidents. This is a global-scale challenge requiring a coordinated response from the international community. Interventions that are implemented do yield positive results, though so far those results have been limited in area scope or duration. In Russia, the problem is growing extremely important in the context of large offshore oil field developments – off Sakhalin and in the Barents, the Caspian, and the Black Sea.
Apart from mining of solid minerals and production of crude oil and gas, underground water is also produced from wells. It is extremely important for society to protect the ecological safety of underground water streams. That safety is ensured through sound spacing of water-source wells over the aquifer and the sequence and intensity of water recovery.
One Challenge For All
Reliable identification of the effects of potential technogenic impacts is quite a challenge in itself. A significant role in its solution can be played by development of computer simulation tools. But effort in this direction would require a universally accepted set of measures and parameters to provide reasonably accurate quantitative assessments of technogenic impacts on the subsoil, potential responses, and consequences. It may be regretted that no such universally recognized set of quantitative criteria has been developed to date, however, some interesting ideas have been suggested. In my opinion, an integrated risk assessment system could be based on monitoring changes in the energy potential of the biospheric components.
Developing and adopting a system of quantitative assessment of technogenic impacts is caused by necessity to establish standards, rules, and quotas regarding acceptable loads on biospheric components, especially on the subsoil. Subsoil management activities must provide for a set of maximum allowed stress limits for all types of technogenic impacts, primarily “extraction” impacts, for it is removal of minerals that is the principal “initiator” of increasingly frequent technogenic earthquakes, rock bursts, and landslides.
The existence of environmental standards formalized in official regulations makes it possible to develop and implement a system of coordinated interventions to ensure ecological safety of the subsoil and mineral development operations. Interventions necessary to prevent adverse technogenic impacts on the subsoil are classified by scope as global, international, national, subnational (regional or interregional) and local (facility-specific).
The following interventions can be recommended to ensure the ecological safety of the subsoil and mineral development operations. At the global level, first of all, an international convention should be adopted to provide for the ecological safety of the subsoil and mineral development operations and a uniform lithological monitoring system should be established. Besides, a UN-sponsored international ecological fund must be set up to implement global environmental interventions to provide for the ecological safety of the subsoil and mineral development operations (to predict and prevent technogenic earthquakes, rock bursts, massive landslides, dust and gas blowouts, and to identify danger zones).
At the level of groups of neighboring states (such as the CIS), in addition to active participation in wider-scope international interventions, the following interventions should be implemented: first, a Model Code for Ecological Safety of the Subsoil and Mineral Development Operations should be developed and adopted; second, a Standard Agreement on Transboundary Air and Water Pollution and Other Technogenic Impacts Management; and third, an interlinked intergovernmental lithological monitoring system should be established.
As for national-level interventions, leading experts maintain that the State Duma of Russia should start drafting a Federal Law On the Ecological Safety of the Subsoil and Mineral Development. At the same time, the existing Ecology and Natural Resources Federal Program for 2002-2010 should identify a set of measures to address relationships with neighboring states in the field of geoecological safety. Besides, it is important to promote geoecological safety business initiatives on the basis of government support and guarantees, in particular by setting up small enterprises and groups thereof to perform environmental interventions in the field of subsoil management.
At the regional level, specific interventions will be determined by specific conditions of the exploration and use of the subsoil resources in question.
This article provides a general idea about the problem of the geoecological safety of the subsoil and mineral development and makes it possible to identify ways and means of environmental management in studying, developing, using, and protecting subsoil resources at various levels. It should be clearly understood that providing for the geoecological safety of the subsoil and mineral development is a global challenge, and no single state, let alone a private company, has the technological or financial capacity to meet that challenge single-handed. Joint action by the world community is required to ensure that the essential balance between the natural environment and civilization is maintained.
