Amu Darya Basin Research Articles

Hydrocarbon generation and expulsion modeling of Jurassic-Cretaceous petroleum system of the Amu Darya Basin, northern Afghanistan

Hydrocarbon generation and expulsion modeling of Jurassic-Cretaceous petroleum system of the Amu Darya Basin, northern Afghanistan

Возможности электроразведки в изучении доюрских образований Северного борта Амударьинской впадины

Возможности электроразведки в изучении доюрских образований Северного борта Амударьинской впадины

Multi-resolution graph-based clustering analysis for lithofacies identification from well log data: Case study of intraplatform bank gas fields, Amu Darya Basin

In this study, we used the multi-resolution graph-based clustering (MRGC) method for determining the electrofacies (EF) and lithofacies (LF) from well log data obtained from the intraplatform bank gas fields located in the Amu Darya Basin. The MRGC could automatically determine the optimal number of clusters without prior knowledge about the structure or cluster numbers of the analyzed data set and allowed the users to control the level of detail actually needed to define the EF. Based on the LF identification and successful EF calibration using core data, an MRGC EF partition model including five clusters and a quantitative LF interpretation chart were constructed. The EF clusters 1 to 5 were interpreted as lagoon, anhydrite flat, interbank, low-energy bank, and high-energy bank, and the coincidence rate in the cored interval could reach 85%. We concluded that the MRGC could be accurately applied to predict the LF in non-cored but logged wells. Therefore, continuous EF clusters were partitioned and corresponding LF were interpreted, and the distribution and petrophysical characteristics of different LF were analyzed in the framework of sequence stratigraphy.

A graphical model for haloanhydrite components and P-wave velocity: A case study of haloanhydrites in Amu Darya Basin

Wave velocities in haloanhydrites are difficult to determine and significantly depend on the mineralogy. We used petrophysical parameters to study the wave velocity in haloanhydrites in the Amur Darya Basin and constructed a template of the relation between haloanhydrite mineralogy (anhydrite, salt, mudstone, and pore water) and wave velocities. We used the relation between the P-wave moduli ratio and porosity as constraint and constructed a graphical model (petrophysical template) for the relation between wave velocity, mineral content and porosity. We tested the graphical model using rock core and well logging data.

Managing the water–energy–food nexus: Gains and losses from new water development in Amu Darya River Basin

Summary According to the UN, the population of Central Asia will increase from its current approximately 65 million people to a well over 90 million by the end of this century. Taking this increasing population into consideration, it is impossible to project development strategies without considering three key factors in meeting the demands of a growing population: water, food and energy. Societies will have to choose, for instance, between using land and fertilizer for food production or for bio-based or renewable energy production, and between using fresh water for energy production or for irrigating crops. Thus water, food and energy are inextricably linked and must be considered together as a system. Recently, tensions among the Central Asian countries over the use of water for energy and energy production have increased with the building of Rogun Dam on the Vakhsh River, a tributary of the Amu Darya River. The dam will provide upstream Tajikistan with hydropower, while downstream countries fear it could negatively impact their irrigated agriculture. Despite recent peer reviewed literature on water resources management in Amu Darya Basin, none to date have addressed the interconnection and mutual impacts within water–energy–food systems in face of constructing the Rogun Dam. We examine two potential operation modes of the dam: Energy Mode (ensuring Tajikistan’s hydropower needs) and Irrigation Mode (ensuring water for agriculture downstream). Results show that the Energy Mode could ensure more than double Tajikistan’s energy capacity, but would reduce water availability during the growing season, resulting in an average 37% decline in agricultural benefits in downstream countries. The Irrigation Mode could bring a surplus in agricultural benefits to Tajikistan and Uzbekistan in addition an increasing energy benefits in Tajikistan by two fold. However, energy production in the Irrigation Mode would be non-optimally distributed over the seasons resulting in the most of hydropower being produced during the growing season. Neither operation mode provides optimal benefits for all the countries, emphasizing how difficult it is to actually reach a win–win scenario across the water–energy–food security nexus in transboundary river basins.

The Cretaceous of the South Kyzylkum and Nuratau Region, Western Tien Shan, Central Uzbekistan

Abstract The Kyzylkum and south Nuratau areas of Central Uzbekistan form the westernmost parts of the Tien Shan and contain rare outcrops of Cretaceous rocks that were deposited along the northern margin of the Amu Darya Basin. The succession can be subdivided into 18 clastic and carbonate facies, and these were deposited in a series of contrasting depositional environments from Aptian through to Maastrichtian times. Broadly, the region comprised a coastal–marine transitional zone, with the coastline advancing and retreating over time, these changes being related to major marine incursions to the east (as far as the Tarim Basin). Tectonic activity along the basin margin, with subsequent uplift of parts of the mosaic of boundary blocks, most probably influenced the development of coeval clastic/carbonate successions in the late Cretaceous.

Estimation of petroleum source rocks based on the crude oil geochemistry in Amu Darya Basin, northern Afghanistan

Estimation of petroleum source rocks based on the crude oil geochemistry in Amu Darya Basin, northern Afghanistan

Division and resources evaluation of hydrocarbon plays in the Amu Darya basin, central Asia

Abstract Based on the newest geological data and exploration achievements and the analysis of hydrocarbon accumulation elements and distribution rules of oil and gas fields, hydrocarbon plays are divided according to the reservoirs in the Amu Darya basin, central Asia. The hydrocarbon plays are evaluated in terms of resources potential and geologic risk, and the favorable hydrocarbon plays are selected using the double factors method of resources-geological risks. Ten hydrocarbon plays have been divided into in the major reservoirs, including the Cenomanian to Turonian sandstones of the Upper Cretaceous, the Hauterivian to Albian sandstones of the Lower Cretaceous, the Callovian to Oxfordian carbonates of the Upper Jurassic, and the Middle-Lower Jurassic sandstones. The undiscovered petroleum resources of the plays, evaluated by the Monte Carlo method, are about 3 308 million tons, in which gas accounts for more than 98%. Considering the geological risks evaluation of the key hydrocarbon elements of reservoirs, traps, migration and preservation, the favorable plays are evaluated and selected using the double factors method of resources-geological risks: two plays of class I, one play of class IIa, two plays of class IIb, three plays of class III, one play of class IVa, and one play of class IVc. The most favorable exploration objectives are the carbonate reservoirs of the Upper Jurassic Callovian-Oxfordian in the Murgab depression.

Sharing Benefits in Transboundary Rivers: An Experimental Case Study of Central Asian Water-Energy-Agriculture Nexus

Cooperation in transboundary river basins is challenged by the riparian countries’ differing needs for water use. This is the case especially in Amu Darya Basin in Central Asia, where upstream Tajikistan is building the Rogun Hydropower Plant (RHP) to increase its energy security, while the downstream countries oppose the plant due to the feared negative impacts to their irrigated agriculture. Several experimental scenarios illustrate how the concept of benefit sharing could be used as a framework to investigate these water-energy-agriculture linkages in a transboundary context. Using a hydro-economic model, we investigate the economic benefits of various scenarios emphasizing agricultural and/or energy production, thus benefiting the riparian countries uniquely. Subsequently, we discuss how benefit-sharing arrangements with different forms of compensations could be used as a mechanism to facilitate transboundary cooperation. Our results indicate that several scenarios have a potential to increase the total energy-agriculture benefits in the basin. Yet, agreeing on the actual benefit-sharing mechanism between the countries poses special challenges as each may require countries to give up some of their anticipated maximum potential benefits. The presented scenarios provide a potential starting point for debates over benefit-sharing arrangements across countries needing to address the water-energy-agriculture nexus.

Conflict over a hydropower plant project between Tajikistan and Uzbekistan

Following the dissolution of the Soviet Union, Central Asian countries struggled to reach an agreement on the use of their shared fresh water resources. The conflict between Tajikistan and Uzbekistan regarding construction of the Rogun Hydropower Plant in the Amu Darya Basin seems deadlocked at present, despite copious efforts made by donor agencies. Therefore, this paper examines each country’s position using the numbers featured in the media.

How would the Rogun Dam affect water and energy scarcity in Central Asia?

The construction of the Rogun Dam in the Amu Darya Basin to increase upstream energy generation creates potential trade-offs with existing downstream irrigation, due to the different timing of energy and irrigation water demands. The present analysis, based on a hydro-economic optimization model, shows that cooperative basin-wide maximization of benefits would lead to large increases in upstream hydropower production and only minor changes in downstream irrigation benefits. However, if upstream stations, including Rogun, are managed unilaterally to maximize energy production, hydropower benefits might more than double while irrigation benefits greatly decrease, thereby substantially reducing overall basin benefits.

An inventory of glacial lakes in the Third Pole region and their changes in response to global warming

No glacial lake census exists for the Third Pole region, which includes the Pamir-Hindu Kush-Karakoram-Himalayas and the Tibetan Plateau. Therefore, comprehensive information is lacking about the distribution of and changes in glacial lakes caused by current global warming conditions. In this study, the first glacial lake inventories for the Third Pole were conducted for ~1990, 2000, and 2010 using Landsat TM/ETM+ data. Glacial lake spatial distributions, corresponding areas and temporal changes were examined. The significant results are as follows. (1) There were 4602, 4981, and 5701 glacial lakes (>0.003km2) covering areas of 553.9±90, 581.2±97, and 682.4±110km2 in ~1990, 2000, and 2010, respectively; these lakes are primarily located in the Brahmaputra (39%), Indus (28%), and Amu Darya (10%) basins. (2) Small lakes (<0.2km2) are more sensitive to climate changes. (3) Lakes closer to glaciers and at higher altitudes, particularly those connected to glacier termini, have undergone larger area changes. (4) Glacier-fed lakes are dominant in both quantity and area (>70%) and exhibit faster expansion trends overall compared to non-glacier-fed lakes. We conclude that glacier meltwater may play a dominant role in the areal expansion of most glacial lakes in the Third Pole. In addition, the patterns of the glacier-fed lakes correspond well with warming temperature trends and negative glacier mass balance patterns. This paper presents an important database of glacial lakes and provides a basis for long-term monitoring and evaluation of outburst flood disasters primarily caused by glacial lakes in the Third Pole.

The Impact of Climate Change on the Water Resources of the Amu Darya Basin in Central Asia

Central Asia is facing an unprecedented juxtaposition of regional climate- and water-related issues, emphasised by a changing climate. We investigate the potential impact of long-term climate change on the availability of water resources in the Amu Darya River, one of the two major rivers that feed the Aral Sea, and its effect on irrigation in the region. Using a water balance accounting model developed for the Amu Darya basin, we find that projected increases in summer temperatures of up to 5 °C by 2070–2099 under a high-emission scenario, combined with likely shifts in the seasonality of precipitation, would lead to an increase in crop water consumptive demand of between 10.6 and 16 % (or between 3.7 and 5.5 km3 y−1) relative to 1961–1990. By the end of the century, 34 to 49 % of the basin’s existing 3.4 million ha of irrigated land would go unirrigated in a 1:20 year drought. Runoff is also expected to decline by between 10 and 20 % on current levels, however contributions to river flows from unsustainable glacial retreat and snow-melt are likely to remain small. While the uncertainty surrounding the precipitation projections is high, the effect of increased temperatures on irrigation practices in the basin is more robust in the long-term.

Structural evolution of the Kopeh Dagh fold-and-thrust belt (NE Iran) and interactions with the South Caspian Sea Basin and Amu Darya Basin

We present a detailed stratigraphic and structural study of the Kopeh Dagh fold-and-thrust belt in NE Iran, which is an investigation of the complex polyphased tectonic history of this belt and its links with the adjacent South Caspian Sea and Amu Darya basins. Based on numerous field surveys, a large amount of 2D and 3D seismic data, borehole data and more than 150 new biostratigaphic datings, a new detailed biostratigraphic chart and 4 main regional cross-sections illustrate the importance of lateral facies variations and structural inheritance in the present-day structure of the belt.After the Cimmerian orogeny corresponding to the closure of the Paleotethys Ocean in Late Triassic/Early Jurassic times, a Middle Jurassic post-collisional rifting event was associated with the deposition of one of the main source rocks of the Kopeh Dagh and the Amu Darya Basin (Kashafrud Formation). Following this rifting event, over 7 km of sediments were accumulated until the Tertiary above a regional post-Triassic unconformity. The occurrence of local uplifts during the Late Cretaceous-Early Paleocene is interpreted as a consequence of regional-scale modification of plate-slab coupling in the Neotethys subduction zone. The main inversion of the Kopeh Dagh occurred at Late Eocene times, when the far-field deformation developed in Eurasia as a consequence of the locking of the Neo-Tethys subduction. This folding phase is sealed in the western part of the belt by a major Eocene-Oligocene unconformity at the base of the thick sedimentary series belonging to the South Caspian Sea Basin. The bulk of sedimentary infill in the South Caspian Sea Basin is Oligocene and younger, and it is probably related to syn-compressional downward flexure of the resistant basement basin at the onset of the Alpine phase. In the eastern part of the Kopeh Dagh, this deformation is characterized by Middle Jurassic graben inversion with evidence of forced folding, short-cuts and as well by larger scale basement uplifts. In contrast, the northwestern part of the belt shows thrust faults involving basement and fault-propagation folds within the sedimentary sequence. The Kopeh Dagh presents tectonic structures that are parallel to the Paleotethys suture zone, which emphasizes the importance of the structural inheritance and inversion processes during the structural evolution of the belt. Finally, a change from a mostly dip-slip to a mostly strike-slip tectonics occurred during the Pliocene within the Kopeh Dagh as a consequence of a major tectonic reorganization in North-East Iran.

Artificial Neural Networks Identification of Lithology-Types in Complex Carbonate from Well Logs, Block K, in Uzbekistan

In oil and gas exploration of Block K in Amu Darya basin Uzbekistan, the reservoir lithologies are mainly in different carbonate rocks, the more types of rocks, the more various reservoir space is, as a result, it brings some difficulties to the reservoir quantitative evaluation. Therefore, according to this situation that the difficulty in identification of complex carbonate lithologies is, in this study block, artificial neural network analysis method is used in this paper. The method combines mud logging, cutting, core data, well logging, studies logging response characteristics of the different types of carbonate rocks, establishes lithology identification index. In this study, the method is used in identifying the types of carbonate rocks, the identified result compared to actual rocks displays about 70.51~87.23%, and it plays the positive role for reservoir quantitative evaluation.

Water, Food, and Energy Security: An Elusive Search for Balance in Central Asia

The development and use of water resources in the Amu Darya Basin remain under debate in the face of increasing population and associated scarcities in water, food, and energy. The upstream riparian, the mountain nation of Tajikistan, wishes to develop its hydropower potential. Three downstream states wish to sustain or increase their economic benefits from water used for irrigation. Growing tensions among the riparian countries on the Vakhsh River, a tributary of Amu Darya, have halted development of Tajikistan’s proposed Rogun Dam. This paper examines the potential for mutually beneficial water development and allocation of water resources to sustain demands for water, food, and energy. Using long-term data on the Basin’s energy potential, water supplies, irrigated land, and crop water demands, this paper analyzes total economic welfare for a future 20-year time horizon. Two water supply scenarios for each of two policy choices are examined. Results show that a constrained economic optimization operation of the Dam has the potential to increase farm income for each riparian country, while producing considerable benefits in hydropower for Tajikistan. Political negotiation among the riparian states and much better data will be needed to discover and implement potential gains indicated by this study.

Glacier and runoff changes in the Rukhk catchment, upper Amu-Darya basin until 2050

A conceptual hydrological model was set up in the upper Panj catchment, the main tributary of Amu-Darya river. After a manual calibration procedure involving model runs with different restrictions, the model reproduced both daily hydrographs of Tanimas river at the Rukhk gauging station (NSE=0.86) and the snow water equivalent of the Irkht station (R2=0.85) in a very satisfactory way. Based on two glacier inventories from the mid-20th century (WGI, World Glacier Inventory) and from 2003 (GLIMS, Global Land Ice Measurements from Space), a simple parameterization scheme based on steady state conditions was applied to infer the ice volumes and glacier areas for these different time periods. Assuming temperature rises of 2.2°C and 3.1°C, which mark the extreme values of regional climate scenarios, the same method was used to extrapolate glacierization to the year 2050. The results show that these temperature rises will reduce the current glacier extent of 431km2 by 36% and 45%, respectively.To assess future changes in water availability, the hydrological model input was modified according to the regional climate scenarios and the resulting glacier changes. The use of an elevation distributed deglacierization pattern is a clear improvement over methods used previously, where the impact on runoff was tested by excluding either the lower half or the total glacier area. The runoff scenarios reveal only a slight reduction in annual runoff, because the glacier area decrease is almost balanced out by enhanced melt rates. However, there is an important seasonal shift of water resources from summer to spring, unfavorably affecting agriculture and irrigation in the lowlands.

Adapting to water scarcity: constraints and opportunities for improving irrigation management in Khorezm, Uzbekistan

Like many irrigation schemes in Central Asia, the one in Khorezm faces a two-fold challenge: on the one side, the severe problems inherited from the past need to be remedied and on the other side, the rising supply–demand gap driven by sharpening competition for water and climate change must be dealt with. Located in the lower part of the Amu Darya basin, Khorezm irrigation and drainage scheme is particularly vulnerable to supply–demand gaps. Promising solutions towards adaptation comprise modified strategies of land and water use towards higher efficiency and flexibility in combination with measures to lessen the constraints of the system itself, which was initially designed for the management of a few, large and uniform production units and not for many diverse and small units. Solutions consist of flexible, modeling-based approaches, re-arranging institutional settings and establishing economic incentive systems. Flexible modeling allows an integrated use of surface and groundwater resources avoiding or minimizing the impact of water stress on yield. Institutional settings strengthen the position of water users via improved participation and transparency of processes in Water Consumers Associations (WCAs). Economic measures support sustainable resource use strategies and improve the functioning of WCAs. The findings could be extrapolated to other regions of Central Asia with similar conditions and challenges.

Carbon and oxygen isotope stratigraphy of the oxfordian carbonate rocks in Amu Darya basin

Based on the detailed research on petrologic and geochemical characteristics of deposition and diagenesis of Oxfordian carbonate rocks in Amu Darya Basin, Turkmenistan, carbon and oxygen isotopes were analyzed. The results show that the paleoenvironmental evolution reflected by the samples with well-preserved original carbon isotopes coincides with the carbon-isotope stratigraphic curve and is almost consistent with the global sea-level curve, the Mid-Oxfordian wide transgression, and the positive carbon-isotope excursion event. The Mid-Oxfordian continuing transgression not only laid the foundation for the development of the Oxfordian reef and shoal reservoirs in Amu Darya Basin but also provided an example for the Oxfordian global transgression and the resulting development of reefs and banks and high-speed organic carbon burial events. The response of oxygen isotopes in diagenetic environment showed that micrite limestones and granular limestones underwent weak diagenetic alteration, and the samples largely retained the original seawater features. Dolomitization and the precipitation of hydrothermal calcites filling solution vugs and fractures before hydrocarbon accumulation occurred in a closed diagenetic environment where the main controlling factor is the temperature, and the diagenetic fluids were from the deep hot brine. The chalkification of the limestones after hydrocarbon accumulation occurred in the oilfield water systems.

Reducing conflict in development and allocation of transboundary rivers

This article explores opportunities for water scarcity to motivate neighboring nations in transboundary basins to cooperate in the development and allocation of water. Climate change raises the importance of discovering foundations for this cooperation. We examine the development of infrastructure and allocation of water in the controversial Amu Darya Basin. An analysis is presented that characterizes politically constrained and economically optimized water-use patterns in the basin. Using information on the basin’s energy potential, water supplies, land area, crop water requirements, and crop economics, we analyze total basin-wide economic welfare over a 20 year period. Results show that the development and operation of the planned Rogun Dam has the potential to secure agricultural benefits downstream for Afghanistan, Uzbekistan and Turkmenistan, while supplying some winter power upstream in Tajikistan in normal water conditions. Results show that the ongoing conflict in the Amu Darya Basin over water infrastructure and allocation has the potential to be resolved in a way to secure economic gains for all four nations. However, patient and difficult political negotiations will be required to achieve the gains indicated. Данная работа исследует возможности мотивации соседних стран для взаимодействия в развитии и распределении воды по причине дефицита водных ресурсов в трансграничных бассейнах. Изменение климата повышает важность нахождения основ для такого рода кооперации. Мы исследовали развитие инфраструктуры распределения воды в противоречивом бассейне реки Амударья. Рассмотренный анализ характеризует политически ограниченное и экономически оптимизированное распределение воды в бассейне. Используя данные по энергопотенциалу, имеющимся водным и земельным ресурсам, потребностям сельскохозяйственных культур в воде и экономике сельскохозяйственных культур, мы провели анализ совокупного экономического благосостояния в бассейне реки на 20-летний период. Результаты показывают, что функционирование Рогунского водохранилища имеет потенциал для обеспечения сельскохозяйственных выгод для стран низовья: Афганистана, Узбекистана и Туркменистана, в то же время обеспечивая некоторое количество зимней энергии для расположенного выше по течению Таджикистана в годы с нормальной водообеспеченностью. Результаты показывают, что текущий конфликт в бассейне реки Амударья за водную инфраструктуру и распределение имеет потенциал разрешиться путем экономического выигрыша для всех четырех стран. Однако, требуется терпение и сложные политические переговоры чтобы достичь указанных выигрышей.