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Assessment of available geothermal resources in the deep oil field is important to the synergy exploitation of oil and geothermal resources. A revised volumetric approach is proposed in this work for evaluating deep geothermal potential in an active oil field by integrating a 3D geological model into a hydrothermal (HT)-coupled numerical model. Based on the analysis of the geological data and geothermal conditions, a 3D geological model is established with respect to the study area, which is discretized into grids or elements represented in the geological model. An HT-coupled numerical model was applied based on the static geological model to approximate the natural-state model of the geothermal reservoir, where the thermal distribution information can be extracted. Then the geothermal resource in each small grid element is calculated using a volumetric method, and the overall geothermal resource of the reservoirs can be obtained by making an integration over each element of the geological model. A further parametric study is carried out to investigate the influence of oil and gas saturations on the overall heat resources. The 3D geological model can provide detailed information on the reservoir volume, while the HT natural-state numerical model addressed the temperature distribution in the reservoir by taking into account complex geological structures and contrast heterogeneity. Therefore, integrating the 3D geological modeling and HT numerical model into the geothermal resource assessment improved its accuracy and helped to identify the distribution map of the available geothermal resources, which indicate optimal locations for further development and utilization of the geothermal resources. The Caofeidian new town Jidong oil field serves as an example to depict the calculation workflow. The simulation results demonstrate in the Caofeidian new town geothermal reservoir that the total amount of geothermal resources, using the proposed calculation method, is found to be 1.23e+18 J, and the total geothermal fluid volume is 8.97e+8 m3. Moreover, this approach clearly identifies the regions with the highest potential for geothermal resources. We believe this approach provides an alternative method for geothermal potential assessment in oil fields, which can be also applied globally.

Unlike other types of renewable energy, geothermal resources represent a stable energy source because they can be exploited regardless of meteorological conditions. In geothermal systems, heat is exchanged between the surrounding rock and the geofluid. Thus the energy potential strongly depends on the temperature of the geofluid, which in turn depends on the working parameters (WPs). The objective of the current work is to specify the optimal WPs (i.e., heat extraction rate, geofluid flow rate, and the temperature difference between the well inlet and outlet) in order to maximize the exploitation of the geothermal resource. The ground thermal properties, geothermal temperature gradient, and well dimensions based on realistic conditions in Qatar and neighboring countries were used to model electricity generation from a geothermal power plant. The simulation shows that the proper selection of the WPs can considerably increase the electricity generation of the power plant. Also, this work shows that the optimal WPs guaranties a sustainable utilization of geothermal sources, which means a constant electricity output of the Rankine turbine over time. For the working conditions in Qatar, it is determined that the maximum electricity generation would be 11 kW during the 25 years (analysis time). To get this maximum electricity generation, the optimal WPs should be as follows: 275 kW for heat extraction rate, 3.7–4.4 kg/s for geofluid flow rate, and 15–17 °C for the temperature difference.

The present research explores the Bañitos-Gollete geothermal field located in the Frontal Andes Cordillera over the Pampean flat-slab. We carried out an audiomagnetotelluric survey in order to define the underground geoelectrical structure and to understand the link between the geothermal fluid flow path and the main geological structures. 2-D audiomagnetotelluric models suggest that the deep-rooted N-S fault system controls the geothermal flow path. We propose a conductive heat-driven system, taking into consideration the geologic setting and the supposed low geothermal gradient of this tectonic environment. The mature Na-Cl waters from Gollete and an estimated reservoir temperature of ~140°C are consistent with this conceptual model. Further investigations are required to assess the geothermal potential of the study area, and the present work likely represents only the first but necessary step in the exploration process. Fil: Barcelona, Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Peri, Verónica Gisel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina Fil: Winocur, Diego Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Favetto, Alicia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geocronología y Geología Isotópica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geocronología y Geología Isotópica; Argentina

The Liaodong area which lies in the Liaoji Belt of northeastern China is rich in geothermal resources, but locating the resources is challenging. Here non-seismic geophysical data, existing geological data and the physical properties of rocks are examined to locate and characterise potential geothermal resources. High-precision gravity, aeromagnetic and magnetotelluric data are analysed to determine the characteristics of the hidden faults in the region and map the spatial distribution of the subsurface rock mass and its properties. The distribution of hidden faults and the basic characteristics of the rock mass were determined via Euler deconvolution of the gravity and aeromagnetic data. The subsurface extension of concealed faults, the spatial distribution of intrusive rocks, and the specific locations of underground thermal storage structures were determined from magnetotelluric data analysis, thereby enabling geothermal energy targets to be identified. The results highlight four potential sites of geothermal energy development in the study area, which indicate that non-seismic geophysical data can provide reliable clues to the geothermal energy potential in a given region.

Geothermal energy has been recognized as an important clean renewable energy. Accurate assessment of geothermal resources is an essential foundation for their development and utilization. The North Jiangsu Basin (NJB), located in the Lower Yangtze Craton, is shaped like a wedge block of an ancient plate boundary and large-scale carbonate thermal reservoirs are developed in the deep NJB. Moreover, the NJB exhibits a high heat flow background because of its extensive extension since the Late Mesozoic. In this study, we used the Monte Carlo method to evaluate the geothermal resources of the main reservoir shallower than 10 km in the NJB. Compared with the volumetric method, the Monte Carlo method takes into account the variation mode and uncertainties of the input parameters. The simulation results show that the geothermal resources of the sandstone thermal reservoir in the shallow NJB are very rich, with capacities of (6.6–12) × 1020 J (mean 8.6 × 1020 J), (5.1–16) × 1020 J (mean 9.1 × 1020 J), and (3.2–11) × 1020 J (mean 6.6 × 1020 J) for the Yancheng, Sanduo and Dai’nan sandstone reservoir, respectively. In addition, the capacity of the geothermal resource of the carbonate thermal reservoir in the deep NJB is far greater than the former, reaching (9.9–15) × 1021 J (mean 12 × 1021 J). The results indicate capacities of a range value of (1.2–1.7) × 1021 J (mean 1.4 × 1022 J) for the whole NJB (

In this study, the chemical and isotopic composition of thermo-mineral springs from the Rosario de la Frontera hydrothermal system was used to construct a conceptual model describing the source regions the thermal fluids and the chemical-physical processes controlling the chemistry of waters and dissolved gases during their underground circulation. The main hydrothermal reservoir, hosted within the Cretaceous Pirgua Subgroup deposits, is fed by meteoric water and shows a Na-HCO3 composition produced by water-rock interactions involving sedimentary formations mostly consisting of conglomerates and sandstones, which are interbedded with alkaline volcanic rocks and shales and limestone deposits. This aquifer also receives significant contributions of crustal CO2 and He from mantle degassing, the latter being likely favored by the regional tectonic assessment that is characterized by a deep detachment (at about 10km depth) in the basement of the Santa Bárbara thick-skinned thrust system and a thinned lithosphere. The uprising thermal fluids mix with a relatively high salinity Na-Cl dominated aquifer produced by the interaction of meteoric water with the Tertiary Anta Formation evaporite. The temperatures of the hydrothermal reservoir, estimated with water geothermometers, are up to 130°C, which are consistent with the thickness of the hydrothermal circuit (2700-3000m) and the relatively high local geothermal gradient (~40°C/km). These results suggest that the heat stored in the fluid phase of RFHS is up to ~1×1018J, a value significantly higher (20%) than that previously estimated assuming an average reservoir temperature of 90°C. Fil: Chiodi, Agostina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina Fil: Tassi, F.. University of Florence. Department of Earth Sciences; Italia. Institute of Geosciences and Earth Resources; Italia Fil: Baez, Walter Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina Fil: Maffucci, R.. Università di Roma; Italia Fil: Invernizzi, C.. Institute for Dynamics of Environmental Processes; Italia Fil: Giordano, G.. Università di Roma; Italia. Institute for Dynamics of Environmental Processes; Italia Fil: Corrado, S.. Università di Roma; Italia Fil: Bicocchi, G.. University of Florence. Department of Earth Sciences; Italia Fil: Vaselli, O.. University of Florence. Department of Earth Sciences; Italia. Institute of Geosciences and Earth Resources; Italia Fil: Viramonte, Jose German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; Argentina Fil: Pierantoni, P.P.. University of Camerino; Italia

The Vicano-Cimino Volcanic District (VCVD) is related to the post-orogenic magmatic activity of the peri-Tyrrhenian sector of Central Italy. The chemical and isotopic compositions of 333 water discharges and 25 gas emissions indicate the occurrence of two main sources: 1) cold Ca-HCO3 to Ca(Na, K)-HCO3 type waters from relatively shallow aquifers hosted in volcanic and sedimentary formations; and 2) thermal Ca-SO4(HCO3) type waters located in a deep CO2-pressurized reservoir, hosted in carbonate-evaporite rocks and separated from the shallow aquifers by thick sequences of low-permeability formations. Carbon dioxide is mainly produced by thermal metamorphic decarbonation within the deepest and hottest parts of the carbonate-evaporite reservoir (delta C-13-CO2 from - 3.1 to + 2.2% vs. VPDB), likely affected by a mantle-rooted CO2. Release of CO2-rich gases from the deep aquifer into the overlying shallow aquifers produces high-CO2 springs and bubbling pools. The spatial distribution of thermal waters and CO2-rich cold discharges is strongly controlled by fractures and faults located in correspondence with buried structural highs. Stable isotopes (delta D and delta O-18) suggest that meteoric water feeds both the shallow and deep reservoirs. The relatively low R/R-a values (0.27-1.19) indicate that He is mainly deriving from a crustal source, with minor component from the mantle affected by crustal contamination related to the subduction of the Adriatic plate. Consistently, relatively high N-2/Ar and N-2/He-3 ratios and positive delta N-15-N-2 values (from 0.91 to 5.7 parts per thousand vs. air) characterize the VCVD gas discharges, suggesting the occurrence of a significant "excess" nitrogen. Isotopic compositions of CH4 (delta C-13-CH4 and delta D-CH4 values from - 28.9 to - 22.1 parts per thousand vs. VPDB and from - 176 to - 138 parts per thousand vs. VSMOW, respectively), and composition of light alkanes are indicative of prevalent thermogenic CH4, although the occurrence of abiogenic CH4 production cannot be excluded. The delta S-34-H2S values (from + 9.3 to + 11.4 parts per thousand vs. VCDT) are consistent with the hypothesis of H2S production from thermogenic reduction of Triassic anhydrites. Gas geothermometry in the H2O-H-2-Ar-H2S system suggests that the VCVD gases equilibrated in a liquid phase at redox conditions controlled by interactions of fluids with the local mineral assemblage at temperatures lower (2000 m) geothermal wells. This confirms that secondary processes, i.e. steam condensation, gas dissolution in shallow aquifers, re-equilibration at lower temperature, and microbial activity, significantly affect the chemistry of the uprising fluids. Thermal water chemistry supports the occurrence in this area of an anomalous heat flow that, coupled with the recent demographic growth, makes this site suitable for direct and indirect exploitation of the geothermal resource, in agreement with the preliminary surveys carried out in the 1970's-1990's for geothermal exploration purposes. (C) 2014 Elsevier B.V. All rights reserved.

Geothermal energy is a clean, green renewable resource, which can be utilized for power generation, heating, cooling, and could effectively replace oil, gas, and coal. In recent years, oil companies have put more efforts into exploiting and utilizing geothermal energy with advanced technologies for heat-tracing oil gathering and transportation, central heating, etc., which has not only reduced resource waste, but also improved large-scale and industrial resource utilization levels, and has achieved remarkable economic and social benefits. Based on the analysis of oilfield geothermal energy development status, resource potential, and exploitation and utilization modes, the advantages and disadvantages of harnessing oilfield geothermal resource have been discussed. Oilfield geothermal energy exploitation and utilization have advantages in resources, technical personnel, technology, and a large number of abandoned wells that could be reconstructed and utilized. Due to the high heat demand in oilfields, geothermal energy exploitation and utilization can effectively replace oil, gas, coal, and other fossil fuels, and has bright prospects. The key factors limiting oilfield geothermal energy exploitation and utilization are also pointed out in this paper, including immature technologies, lack of overall planning, lack of standards in resource assessment, and economic assessment, lack of incentive policies, etc.