OIL AND GAS COMPLEX CREATION IN YAKUTIA: ENVIRONMENTAL ISSUES

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1 OIL AND GAS COMPLEX CREATION IN YAKUTIA: ENVIRONMENTAL ISSUES I.P. Konstantinov Melnikov Permafrost Institute SB RAS, Yakutsk Russia Abstract The creation of the local oil production and oil processing in the Sakha Republic (Yakutia) is considered. It is shown that permafrost underlies practically all the territory of the Republic, thus creating challenges to its oil and gas deposit development. The experience of Yakutian gas deposit development can be usefully applied to the development of the oil deposits. It is stressed that such detrimental geological processes as gullying, bog formation and thermokarst development are conditioned by anthropogenically-induced alterations of the natural environment. It is emphasized that environmental pollution would have disastrous consequences in Yakutia, more serious than in western Russia, because of the lower rate of biochemical oxidation in soils as well as the lower self-cleaning capacity of water reservoirs of the region due to low temperatures. The paper presents the conception of engineering and environmental security for the development of the oil and gas industry in Yakutia. Introduction Yakutia is the most remote, largest and richest mineral resource region in the Russian Federation. Oil production and processing is beginning there at present. Until recently, gas has been produced in the region, but oil products have been delivered from other parts of the country. The goal has been set to maximize internal oil production in the next five years. To assist in this task, we utilized the experience of thirty years of gas development in central Yakutia and gas and oil development in northern Tyumen (Mazur, 1989; Mazur et al., 1990). The first gas pipeline in Yakutia was constructed between Taas-Tumus and Yakutsk in ; protective linings of various kinds were applied there. Later on, gas pipelines were built primarily underground, as these proved to be more reliable than both elevated and surface ones. The reliability of gas production and transport is of crucial importance in Yakutia, where any breakdown, however slight, is an ordeal for consumers, especially in long cold winters. Almost the entire territory of central Yakutia is underlain by continuous ice-rich permafrost. That is why many construction problems are difficult to solve. In particular, all construction activity is prohibited in certain areas in summer. Nevertheless, the construction of gas pipelines and accompanying facilities cannot avoid all disturbance of the natural environment and the consequent development of negative geocryological processes (thaw subsidence, thermal erosion, frost heave etc.) which endanger the reliability of pipelines and other structures. The most serious problems are caused by the destruction of vegetation cover in the areas of massive ground ice occurrence. Oil production should involve environmental protection, profiting by the mistakes made during gas production and transport. Many negative consequences were experienced in the years when UstÕ-Viliuysk, Mastakhsky, Sredneviliuysky and Srednebotuobinsky gas condensate deposits were developed: wood was either wasted or unpractically utilized; lands became polluted and cluttered up with industrial waste; air and soil were polluted by gas condensate; forests were swamped and flooded; the permafrost heat balance was changed, and negative cryogenic processes developed. The pernicious influence of gas pipeline construction and operation on the environment was due to poorly planned projects without a well thought-out set of environmental measures. Until the mid-80õs, all projects entirely lacked environmental provisions. Very limited environmental measures, though formally prescribed in planning and estimate calculations, usually did not do much good. The last ten years have been marked by radical changes in environmental attitudes in Russia. It is now understood that it is much more profitable to prevent possible negative environmental consequences at the project stage rather than to eliminate defects and struggle with the consequences of ecological disasters later. In 1994, the Statute on Environmental Effect Evaluation (SEFE) came into force in the Russian Federation. Now feasibility studies of oil and gas pro- I.P. Konstantinov 601

2 duction projects must include the estimation of environmental effects, i.e., ecological provisions and state expertise are now obligatory for all stages of any project. Problem statement The environmental situation in Yakutia is already grave and obviously changing for worse. The problem of environmental security of the gas/oil and oil/condensate deposit development is urgent and requires an appropriate scientific approach. Among the problems to be solved are: the interaction between oil and gas industrial structures and the environment; the improvement of ecological regulations for construction and operation of such structures; the environmental aspects of the problem of higher reliability of engineering structures. Results Currently there are over 30 gas, gas and oil, and gas condensate deposits discovered in the Sakha Republic (Yakutia). Six of these are already being exploited. Geographically they are situated in the western (Srednebotuobinsky oil and gas condensate deposit) and central (Sredneviliuysky gas condensate deposit) parts of the Republic. EFFECT OF GAS PIPELINE ROUTES In central Yakutia, the reliability and stability of the main gas pipelines are complicated by the diversity of natural conditions. Thick underground ice and soils with high ice content are widespread here, and their degradation disrupts construction and operation of the main roads. This leads to destruction of plant and animal populations in the region. Permafrost degradation is also influenced by short-term fluctuations of total radiation, air temperature and precipitation level, which have been common for the last years. Thermally unstable features include areas with ice wedges, sparse forests with peat mounds and slopes prone to erosion. Revegetation starts here only when anthropogenic effects get weaker; however, the composition of vegetation species changes substantially. In this way, deciduous forests with cowberry are replaced by birch forests with a mixed herbs. Sedge becomes dominant in such areas due to their paludification, finally resulting in hummocky bogs. Geothermal data analysis shows that forest clearing away from the gas pipeline effect zone increases the average annual temperature by C, except in areas of developing aeolian processes (tukulans) where the soil temperature regime does not change. Active layer depths have increased in practically all landscape types because of the alteration of heat exchange (by times in dry areas and by times in areas with high soil moisture content). Slow climate warming of the latest decades also contributes. Insignificant (by times) changes of active layer depth are registered in herbaceous areas where the ve- Figure 1. One of numerous gullies potentially dangerous for the pipeline stability on the slope of Chakyia (Kenkeme river tributary) River bank. 602 The 7th International Permafrost Conference

3 Figure 2. Location map of the Promyshlenny-Yakutsk and Mastakh-Yakutsk-Pokrovsk gas pipelines. getation is quickly restored after destruction (river mouths, mature alasses and alas-like valley bottoms). Thermal erosion is widely developed along the gas pipeline route (Figure 1). To a greater or lesser extent, it affects practically all slopes. The gullies reach sizes of 3-5 m depth, 8-12 m width and m length. There are no methods for numerically predicting thermal erosion, so only the actual observed data can be used to evaluate its intensity. In a sandy part of Mastakh- Yakutsk (Figure 2) pipeline route, thawing ice has formed a depression 0.5 m deep and 80 m long in just one spring. Such a high erosion rate is typical only for the first 3-5 years. Later the gully growth rate slows to several meters per year, and a gully stabilizes in 7-10 years. Recent thermokarst forms (ponds, small lakes and thaw depressions) related exclusively to surface disturbance of the natural landscapes, are ubiquitous along the pipeline route where ice wedges are present. Maximum thaw depression sizes ( m) are common for the road along the pipeline route; in other cleared areas, polygonal ditches are as deep as m. The Mastakh-Yakutsk gas pipeline crosses various permafrost landscapes, including numerous depressions filled with lakes or swamps. Here the active layer has increased, thermokarst and heave processes have been activated and vegetation composition has changed. As a result, significant lengthwise and transverse displacements are common, up to and including floating and buckling (Figure 3). The gas of Yakutian fields is transported at -16 C to -20 C in winter (October 1 to April 30) and -14 C to -16 C in summer (May 1 to September 30). The gas reaches its destination (the city of Yakutsk) after 380 km, equilibrated to the temperature of the surrounding soils ( C in summer or to -6.7 C to -7.1 C in winter). Several accesses were provided along the route for regular temperature measurements on the pipeline walls and surrounding soils, pipe displacement estimates, settlement and buckling observations. We have registered lengthwise variations in gas pipeline wall temperature up to 6 C among its underground sections and up to 24 C between the underground and surface sections. The gas temperature regime is substantially influenced by the length of the surface section that follows an underground one. The observations showed the gas temperature to be close to air temperature over the first 5-6 km of the surface section, while the temperature gradients are considerably higher on the pipeline walls (6.5 C/km in winter and 10 C/km in summer). At the boundary between surface and underground sections, as a result of heat exchange between the pipeline wall and the soil, the pipeline wall temperature becomes equal to the soil temperature within the first km. I.P. Konstantinov 603

4 Figure 3. Pipeline buckling with pipe exposure. Soils thaw unevenly along the pipeline due to their different moisture content and dispersibility, as well as different pipe depths. In May-June, the soil thawing rate is 1.5 times higher around the pipeline than in the points outside the pipeline thermal effect zone (i.e., on the cleared area). On the other hand, in early winter the soils freeze completely around the pipeline, whereas in the remaining cleared area, freezing continues to late November - early December. Vertical displacement of the underground pipe in drained sections is comparable with the soil heave rate, and exceeds by a factor of 10 the longitudinal and transverse displacements. Problems of pipeline longitudinal stability occur in the forms of arcs, horizontal bends, buckling, floating Table 1. Characteristics of oil from Srednebotuobinsky and Talakan fields and exposures. These are caused by disturbance of natural drainage and bog formation, pipe burial at lesser depths than designed for, improper ballasting or inadequate loading. Where the pipe is buried to the design depth of 0.8 m, there has not been any stability loss. OIL PRODUCTION AND TRANSPORTATION The Sakha Republic (Yakutia) has started its oil production and processing. The interaction of the oil industry with the environment differs considerably from that of the gas production facilities. For instance, the oil pipeline design must consider the relationship between the hydraulic regime of the oil flow and the changes of oil properties with its movement along the pipeline at low temperatures. Thaw settlement must be taken into account by appropriate engineering solutions to prevent pipeline rupture. Analysis of oil of the Yakutian Srednebotuobinsky and Talakan deposits shows that its properties allow easier solution for some technical problems. For example, its low viscosity and low congelation temperature remove the problem of the winter startup (Table 1). It is not necessary to heat up the oil, or to evaluate the admissible interruption time for emergency shutdowns. Environmental requirements necessitate the prediction of cryogenic processes and the evaluation of indirect effects of the oil industry upon the ecological environment (through changes in soil, surface and underground water). It should be noted that the rate of soil biochemical oxidation is very low and that the selfcleaning capacity of water reservoirs is an order of 604 The 7th International Permafrost Conference

5 magnitude lower in the Far North than in the European Russia, because of the cooling effect of underlying and surrounding frozen grounds. That is why in Yakutia the consequences of environmental pollution are potentially disastrous. PRINCIPLES OF PREPARATION AND CONSTRUCTION OF OIL AND GAS FACILITIES On the basis of the experience accumulated in design, construction and operation of oil deposits in northern Tyumen, the Permafrost Institute SB RAS conceived of environmental provisions comprising four principles of preparation and construction for oil and gas production and transport facilities (Konstantinov, 1996). The first principle preserves the natural environment by avoiding direct contact between the landscape and machinery or structures, providing protective filling and embankments for the latter, or planning the major operations for the winter period, after the active layer is frozen. The second principle means the formation of an objectõs quality and reliability at the design stage. The design options should envisage minimum damage to natural conditions and minimum negative effects on the particular technological facilities. This presumes prior environmental research, evaluation of the tolerance of the geocryological environment to various types of human-induced pressures, definition of the content and format of environmental measures necessary for particular terrain, and estimation of the negative effects of geological processes and phenomena on the constructed facilities. The third principle is connected with construction as one of the most important stages of quality formation, is aimed at creating an object that complies with the design. It is necessary to guarantee the reliability through 100% quality control in the course of construction. In the absence of requirements to determine the maximum admissible environmental effects, as well as the proper instruments to control such effects, a major role can be played by environmental supervision agencies that should include both the local administration and regional environmental committees. Environmental controls should not be reduced to occasional measurements of the composition and properties of soil and underground water. It must monitor changes in terrain, the strains and deformations of facilities, and control the performance of the effective environmental laws, rules and regulations, and the timely construction of environmental protection facilities. through the higher reliability of engineering structures provided by their proper thermal regime that will exclude excessive permafrost thaw, by their mending and repair, and by efficient control of the natural processes and environmental effects of technological activity. These ideas served as the basis for the draft of ÔEnvironmental Protection Regulation for Yakutia Oil and Gas ConstructionÕ that is to append and detail organizational procedures of land tenure foreseen in the normative documents and legislative acts of the Russian Federation. Conclusion With the start of the market economy in Russia the importation of oil products from outside to the Sakha Republic (Yakutia) became unprofitable. Therefore the goal was set that in the next five years, the RepublicÕs oil requirements should be satisfied to the maximum possible extent by its own resources. To do this, many oil and gas industrial, geological, production and processing enterprises have been started in western Yakutia. Oil from the Srednebotuobinsky and Talakan deposits has low viscosity and a low congelation temperature that makes it favorable to be transported within underground pipelines. However, their development and construction will inevitably cause painful environmental responses. Therefore, the problem of protecting the fragile northern environment from negative development effects is crucial. Moreover, the current environmental situation in Yakutia is already serious, with a tendency to get even worse. An improved reliability of major pipelines and their facilities has environmental implications, because it is closely connected with fragility and sensitivity of permafrost landscapes, as well as the low rate of biochemical oxidation in the soils and low self-cleaning capacity of natural water reservoirs. To improve the quality of design, construction and operation of the oil and gas facilities in Yakutia, the Melnikov Permafrost Institute SB RAS is preparing a draft document to regulate organizational procedures of land tenure, to formulate norms of environmental protection from negative anthropogenic effects and to determine methods of their prevention. The fourth principle assumes prevention of accidents, faults and breakdowns in the oil and gas industry, including its environmental protection facilities, I.P. Konstantinov 605

6 References Konstantinov, I.P. (1996). Engineering Conception of Environmental Regulations of Oil and Gas Industrial Objects Construction in Yakutia. In Proceedings of the 1 st International Conference of the Northern Forum Academy. Yakutsk, p. 105 (In Russian). Mazur, I.I. (1989). Problems of Engineering Ecology of Oil and Gas Complex and Ways of Their Effective Solution. In Ecology of Oil and Gas Complex. Proceedings of the 1 st All- Union Conference in Nadym. Vol. 1, P. 1. Moscow, pp. 3-8 (In Russian). Mazur, I.I., Ivantsov, O.M. and Moldavanov, O.I. (1990). Constructive Reliability and Environmental Safety of Pipelines. Nedra, Moscow (264 pp.) (In Russian). 606 The 7th International Permafrost Conference