Поиски гидрогеотермальных резервуаров геофизическими методами в Монголо-Байкальском регионе

The aim of this paper is to combine different types of information necessary for a first rather qualitative assessment of deep geothermal reservoirs in the region of Luxembourg. Within the geological framework, the study area encompasses Luxembourg and the surrounding areas of Belgium, Germany, and France. On the one hand, the focus is laid on low-enthalpy hydrothermal reservoirs in Mesozoic aquifers in the Trier-Luxembourg Embayment. On the other hand, petrothermal reservoirs in the Devonian basement of the Ardennes and Eifel regions are considered for exploitation by Enhanced/Engineered Geothermal Systems (EGS). For geothermal exploration and exploitation purposes, geological, thermal, hydrogeological and structural data are necessary. Among the Mesozoic aquifers, the Buntsandstein aquifer characterized by temperatures of up to 50°C is a suitable hydrothermal reservoir that could be exploited by means of heat pumps or provide direct heat for various applications. The most promising area is the zone of the SE-Luxembourg Graben. The aquifer is the warmest underneath the upper Alzette valley and the limestone plateau in Lorraine, where the Buntsandstein aquifer lies below a thick Mesozoic cover. At the base of an inferred Rotliegend graben in the same area, temperatures of up to 75°C are expected. However, geological and hydraulic conditions are uncertain. In the Lower Devonian basement, thick sandstone-/quartzite-rich formations with temperatures >90°C are expected at depths >3.5 km and likely offer the possibility of direct heat use. The setting of the Südeifel (South Eifel) region, including the Müllerthal region near Echternach, as a tectonically active zone may offer the possibility of deep hydrothermal reservoirs in the fractured Lower Devonian basement. Based on recent data on the structure of the Trier-Luxembourg Basin, the new concept presents the Müllerthal-Südeifel Depression as a Cenozoic tectonic structure that is still mobile and relevant for geothermal exploration. Beyond direct use of geothermal heat, the expected modest temperatures at 5 km depth (about 120°C) and increased permeability by EGS in the quartzite-rich Lochkovian could prospectively enable combined geothermal heat production and power generation in Luxembourg and the western realm of the Eifel region.

The Department of Energy's Geothermal Program serves two broad purposes: (1) to assist industry in overcoming near-term barriers by conducting cost-shared research and field verification that allows geothermal energy to compete in today's aggressive energy markets; and (2) to undertake fundamental research with potentially large economic payoffs. The four categories of work used to distinguish the research activities of the Geothermal Program during FY 2000 reflect the main components of real-world geothermal projects. These categories form the main sections of the project descriptions in this Research Update. Exploration Technology research focuses on developing instruments and techniques to discover hidden hydrothermal systems and to explore the deep portions of known systems. Research in geophysical and geochemical methods is expected to yield increased knowledge of hidden geothermal systems. Reservoir Technology research combines laboratory and analytical investigations with equipment development and field testing to establish practical tools for resource development and management for both hydrothermal reservoirs and enhanced geothermal systems. Research in various reservoir analysis techniques is generating a wide range of information that facilitates development of improved reservoir management tools. Drilling Technology focuses on developing improved, economic drilling and completion technology for geothermal wells. Ongoing research to avert lost circulation episodes in geothermal drilling is yielding positive results. Conversion Technology research focuses on reducing costs and improving binary conversion cycle efficiency, to permit greater use of the more abundant moderate-temperature geothermal resource, and on the development of materials that will improve the operating characteristics of many types of geothermal energy equipment. Increased output and improved performance of binary cycles will result from investigations in heat cycle research.

This study is aimed at identifying the ultradeep gas reservoir structure and gas‐rich areas in the middle section of the southern margin of the Junggar Basin. Based on high‐precision microgravity data collected from the complex terrain areas of Huxi and Tudong in the middle section of the southern margin of the Junggar Basin, residual gravity anomalies of deep reservoirs were extracted after numerical conversion and various corrections. Combined with comprehensive geological interpretation, favorable areas for natural gas exploration in the Lower Cretaceous and Upper Jurassic were delineated. The results demonstrate that high‐precision microgravity detection offers significant advantages including cost‐effectiveness, environmental friendliness, rapid implementation, and the ability to reflect overall planar effects in optimizing gas reservoir targets. The microgravity results show strong consistency with geological features seismic profile characteristics and gas enrichment patterns observed in drilling wells. Continuous and stable low residual gravity anomalies effectively characterize gas traps and enrichment zones. As a geophysical method for oil and gas exploration, microgravity technology can be integrated with seismic methods or applied independently in areas where seismic data acquisition is challenging. This study significantly expands the application of microgravity detection in natural gas exploration marking its first use in the exploration of deep sandstone gas reservoirs at burial depths exceeding 7300 m. Moreover, in complex mountainous terrain where seismic acquisition and processing are difficult, high‐precision microgravity detection proves to be an effective technique for gas reservoir exploration.

Assessing the monitorability of CO2 saturation in subsurface saline aquifers

This paper continues our investigation showing the necessity of applying organic geochemistry methods in combination with methods of geology and geophysics while prospecting and developing oil fields (Kukinsky, 1994). To emphasize the necessity of geochemical data, this paper pays special attention to negative results arising from neglecting these data. Ignoring geochemical data very often leads to an incorrect conception of the geological reservoir model and as a result large investments are spent on driiling dry wells. This was confirmed in the course of prospecting, exploration and development of some oil fields in Pre-Caspian depression western zone and near-by zones.

Summary Shale oilgains much attention as an unconventional resource, which has a potential of significant oil production. Moreover, the technology of horizontal drilling and hydraulic fracturing has encouraged the exploration and development of shale oil reservoirs. An optimal hydraulic fracturing design is essential to achieve a high oil production rate. However, industry is still faced with many challenging issues in hydraulic fracturing optimization, especially under geological and economic uncertainties. These uncertainties can result in a significant increase in capital costs and negative effects on project revenue. This paper presents innovative hydraulic fracturing robust optimization fordevelopment of unconventional reservoirs to reduce the current challenges and minimize the future investment expenses. We first address a sensitivity analysis for creatingmultiple scenerios of a simulation model, consideringuncertainties of geology and reservoir properties. Most of the previous hydraulic fracturing optimization workflows often ignoredthese uncertainty parameters; therefore, the conventional optimal solution obtained based on a single realization may deviate severely from the actual optimality. To capture geological and reservoir uncertainties, a large number of geological reservoir realizations must be generated honoring geological constraints. Hydraulic fracturing parameters (e.g., fracture half-length, fracture spacing, and fracture height), injection composition and operating conditions are optimized simultaneously based on these multiple geological realizations. The sensitivity analysis results indicate that the four parameters that strongly affect the shale oil production include matrix permeability, fracture half-length, fracture spacing and rock compressibility. To maximize oil recovery, a series of physics-based optimizations have been performed for a hydraulic fracturing design by applying the Partical Swarm Optimization algorithm in a robust optimizer. Both the conventional optimization, based on a single geological realization and robust optimization, based on multiple geological realizations have been conducted. After the conventional optimization process, the ultimate oil recovery yields about 18.63% OOIP. Then the robust optimization procedure is applied with 210 realizations. Due to the high computational cost of shale oil simulations, it is impractical to use all generated models in the robust optimization workflow. Thus we propose a method for the robust optimization of hydraulic fracturing (HF) and gas injection composition based on a small set of geological realizations that represent the overall uncertainty of a reservoir. This is achieved by ranking all realizations according to the performance of each realization in terms of cumulative oil production. The comparison shows that the robust optimization increases all the NPV percentile values. This indicates the increased robustness of the optimal solution under uncertainties and thus an adoption of the robust optimization procedure can significantly reduce the project risk. This research is to present an innovative optimization approach which is fast and robust and can be used to efficiently capture the uncertainties of the key factors including geology, reservoir properties, and economic variation.

Progress is reported for the Idaho Geothermal program between October 1, 1979 and March 31, 1980. Progress on the 5-MW Pilot Power Plant at the Raft River Geothermal Test Site is summarized including construction, steady-state and transient analyses by computer modeling, the geothermal water treatment program, and additional experimental and theoretical work on direct contact heat exchangers. Asbestos-cement pipe failures in the geothermal fluid supply and injection system are also summarized. The successful automatic control-mode testing of the Prototype Power Plant is reported. A continuing direct applications experiment in aquaculture is outlined, and a proposal to study various ramifications of irrigating agricultural and range lands with spent geothermal fluid is described briefly. Also outlined is the second experimental hydraulic fracture treatment of a geothermal well at Raft River as part of the National Well Stimulation Program. The improvements to the Raft River site facilities are described, and progress in providing technical information and assistance in the Outreach, or User Assistance program presented. Also presented is a new DOE program, the User Coupled Confirmation Drilling Program, which is intended to reduce the financial risk of hydrothermal reservoir exploration by the private sector. Progress reports are also included on DOE's Program Opportunity Notice (PON) Program demonstration projects and Program Research and Development Announcement (PRDA) Program study projects.

Renewable energy resources can indisputably minimize the threat of global warming and climate change. However, they are intermittent and need buffer storage to bridge the time-gap between production (off peak) and demand peaks. Based on geologic and geochemical reasons, the North German Basin has a very large capacity for compressed air/gas energy storage CAES in porous saltwater aquifers and salt cavities. Replacing pore reservoir brine with CAES causes changes in physical properties (elastic moduli, density and electrical properties) and justify applications of integrative geophysical methods for monitoring this energy storage. Here we apply techniques of the elastic full waveform inversion FWI, electric resistivity tomography ERT and gravity to map and quantify a gradually saturated gas plume injected in a thin deep saline aquifer within the North German Basin.For this subsurface model scenario we generated different synthetic data sets without and with adding random noise in order to robust the applied techniques for the real field applications. Datasets are inverted by posing different constraints on the initial model. Results reveal principally the capability of the applied integrative geophysical approach to resolve the CAES targets (plume, host reservoir, and cap rock). Constrained inversion models of elastic FWI and ERT are even able to recover well the gradual gas desaturation with depth. The spatial parameters accurately recovered from each technique are applied in the adequate petrophysical equations to yield precise quantifications of gas saturations. Resulting models of gas saturations independently determined from elastic FWI and ERT techniques are in accordance with each other and with the input (true) saturation model. Moreover, the gravity technique show high sensitivity to the mass deficit resulting from the gas storage and can resolve saturations and temporal saturation changes down to ±3% after reducing any shallow fluctuation such as that of groundwater table.

Clastic reservoir exploration, development, and exploitation are inherently complex with recovery depending largely on the understanding of sand body architecture and interlayered clayey/silty baffles and barriers. Numerous data collection techniques and methods are now widely available for helping to enrich reservoir outcrop analogue data extraction from the well scale to the larger seismic scale. This integrated study uses the inherited, combined data from a localized light detection and ranging survey, measurements taken from a portable handheld spectrometer and air permeameter, in addition to total (or absolute) porosity measurements from thin sections to assist with the analysis of components influencing the interpretation of a digitally analyzed fluvial meanderbelt system outcrop. The purpose is not to perform a detailed reservoir characterization or to model a potential reservoir, but rather to study a section of a reservoir analogue and apply reservoir geology with integrated data collection techniques to highlight potential benefits and shortcomings of this type of approach. A point cloud survey generated from light detection and ranging, coupled with other tools including a portable handheld spectrometer and permeameter, supplements data from the light detection and ranging scan and increases the confidence of interpretations. Spectrometer measurements recorded at the outcrop are used to generate a pseudo-gamma log. Handheld air permeameter measurements give a sense of the permeability of corresponding lithologies, as well as the variability in permeability of the reservoir both laterally and vertically. Light detection and ranging also provides important information regarding rock properties. The high detail of the outcrop images is used for the assessment of reservoir characteristics. The reservoir data leads to an increased understanding of subsurface reservoirs, particularly of the fluvial meanderbelt type. This study shows the importance and drawbacks of a combined digital data collection approach for the analysis of a sedimentary outcrop.