Reuse of Decommissioned Hydrocarbon Wells in Italian Oilfields by Means of a Closed-Loop Geothermal System

Geological and geophysical exploration campaigns have ascertained the coexistence of low to medium-temperature geothermal energy resources in the deepest regions of Italian sedimentary basins. As such, energy production based on the exploitation of available geothermal resources associated with disused deep oil and gas wells in Italian oilfields could represent a considerable source of renewable energy. This study used information available on Italian hydrocarbon wells and on-field temperatures to apply a simplified closed-loop coaxial Wellbore Heat Exchanger (WBHE) model to three different hydrocarbon wells located in different Italian oilfields (Villafortuna-Trecate, Val d’Agri field, Gela fields). From this study, the authors have highlighted the differences in the quantity of potentially extracted thermal energy from different analysed wells. Considering the maximum extracted working fluid temperature of 100 °C and imagining a cascading exploitation mode of the heat accumulated, for Villafortuna 1 WBHE was it possible to hypothesise a multi-variant and comprehensive use of the resource. This could be done using existing infrastructure, available technologies, and current knowledge.

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An Improved Closed-Loop Heat Extraction Method From Geothermal Resources

Journal of Energy Resources Technology ◽

10.1115/1.4023175 ◽

2013 ◽

Vol 135 (4) ◽

Cited By ~ 5

Author(s):

Arash Dahi Taleghani

Keyword(s):

Contact Area ◽

Geothermal Energy ◽

Closed Loop ◽

Produced Water ◽

Heat Extraction ◽

Working Fluid ◽

Induced Earthquakes ◽

Geothermal Resources ◽

Major Mechanism ◽

Pressure Changes

Disposal of produced water and induced earthquakes are two major issues that have endangered development of the geothermal energy as a renewable source of energy. To avoid these problems, circulation of a low-boiling working fluid in a closed loop has been proposed; however; since the major mechanism in this method for heat extraction is conduction rather than convection and additionally the heat conduction is limited to the wellbore surface. To overcome this shortcoming, the formation can be fractured with high conductivity material (for instance, silicon carbide ceramic proppants or cements with silane and silica fume as admixtures) to artificially increase the contact area between the “working fluid” and the reservoir. Our calculations show that fracturing increases the contact area by thousand times, additionally, the fracturing materials reinforce and stressed the formation, which reduce the risk of seismic activity due to temperature or pressure changes of the system during the production.

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Study of Lithium Bromide-Water Binary Solution in the Application of Hot Springs Geothermal Energy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.886.489 ◽

2014 ◽

Vol 886 ◽

pp. 489-495

Author(s):

Ze De Liang ◽

Shu Jie Wang

Keyword(s):

Air Conditioning ◽

Hot Springs ◽

Binary Solution ◽

Lithium Bromide ◽

Gas Content ◽

Practical Significance ◽

Working Fluid ◽

Geothermal System ◽

Medium Temperature ◽

Geothermal Resources

The main geothermal resources in China are low or medium-temperature geothermal resources, these are more than 3000 hot springs, which of above 60 °C account for 24 percent of total, those are more than 720. In these hot springs bases for tourism and leisure and spa medical, the demand of electricity and air-conditioning is relatively large, so these is a very important practical significance to develop low or medium-temperature geothermal resources technology. If hot springs geothermal system uses lithium bromide-water azeotropic binary mixtures as working fluid, which not only reduces the heat loss of temperature difference, but also plays the advantages in thermodynamics and environmental aspects. Three systems of this article described all use water vapor as the working fluid, their characteristics are analyzed and compared, respectively. By analysis found that: when the demand is only for power generation and non-condensable gas content in hot springs geothermal water is not too high, the single-stage flash evaporation electrical system is more favorable; because of hot springs primarily for leisure travel and medical care function, and the demand for air conditioning and refrigeration is also large, so the combined system is more favorable.

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Oil and Gas Drilling Optimization Technologies Applied Successfully to Unconventional Geothermal Well Drilling

10.2118/205965-ms ◽

2021 ◽

Author(s):

Junichi Sugiura ◽

Ramon Lopez ◽

Francisco Borjas ◽

Steve Jones ◽

John McLennan ◽

...

Keyword(s):

Geothermal Energy ◽

Oil And Gas ◽

Optimization Techniques ◽

Geothermal System ◽

Well Drilling ◽

Geothermal Well ◽

Gas Drilling ◽

Drilling Tools ◽

Drilling Optimization ◽

Oil And Gas Drilling

Abstract Geothermal energy is used in more than 20 countries worldwide and is a clean, reliable, and relatively available energy source. Nevertheless, to make geothermal energy available anywhere in the world, technical and economic challenges need to be addressed. Drilling especially is a technical challenge and comprises a significant part of the geothermal development cost. An enhanced geothermal system (EGS) is a commercially viable thermal reservoir where two wells are interconnected by some form of hydraulic stimulation. In a commercial setting, fluid is injected into this hot rock and passes between wells through a network of natural and induced fractures to transport heat to the surface system for electricity generation. To construct EGS wells, vertical and directional drilling is necessary with purpose-built drilling and steering equipment. This is an application where oil-and-gas drilling tools and techniques can be applied. A recent well, 16A(78)-32, drilled as part of the US Department of Energy's (DOE's) Utah Frontier Observatory for Research in Geothermal Energy (FORGE) program, highlights some of the technical challenges, which include drilling an accurate vertical section, a curve section, and a 5300-ft 65° tangent section in a hard granitic formation at temperatures up to 450°F (232°C). Extensive downhole temperature simulations were performed to select fit-for-purpose drilling equipment such as purely mechanical vertical drilling tools, instrumented steerable downhole motors, measurement-while-drilling (MWD) tools, and embedded high-frequency drilling dynamics recorders. Downhole and surface drilling dynamics data were used to fine- tune bit design and motor power section selection and continuously improve the durability of equipment, drilling efficiency, and footage drilled. Drilling optimization techniques used in oil and gas settings were successfully applied to this well, including analysis of data from drilling dynamics sensors embedded in the steerable motors and vertical drilling tools, surface surveillance of mechanical specific energy (MSE), and adopting a drilling parameter roadmap to improve drilling efficiency to minimize drilling dysfunctions and equipment damages. Through drilling optimization practices, the instrumented steerable motors with proper bit selections were able to drill more than 40 ft/hr on average, doubling the rate of penetration (ROP), footage, and run length experienced in previous granite wells. This paper presents a case study in which cutting-edge oil-and-gas drilling technologies were successfully applied to reduce the geothermal well drilling time by approximately half.

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Geothermal-Driven Ejector Refrigeration System

Volume 6A: Energy ◽

10.1115/imece2013-64949 ◽

2013 ◽

Author(s):

Mark Anthony B. Redo ◽

Menandro S. Berana

Keyword(s):

Geothermal Energy ◽

System Analysis ◽

Control Volume ◽

Phase Region ◽

Coefficient Of Performance ◽

Irreversible Processes ◽

Fluid Temperature ◽

Refrigeration System ◽

Two Phase ◽

Geothermal Resources

A mathematical model of a heat-driven ejector refrigeration system that uses geothermal energy as the heat source was established. Philippine low-enthalpy geothermal resources were investigated and became the bases in computing for the heat at the generator part of the ejector refrigeration system. Analysis and comparison of the performance of the cycle considering working fluids like ammonia (R717) and R134a as the refrigerants were conducted. The properties of those fluids were based on an available thermodynamic database of various refrigerants. The governing principles and conservation equations for energy, mass and momentum were successively applied to control volume of ejector components. The properties for both fluid and flow were solved iteratively for isentropic and irreversible processes wherein entropy generation and frictional losses were accounted for. This included simulation of flows in two-phase region. Input parameters were set like the generating temperature and condensing temperature. The range of 60 to 100 °C available geothermal fluid temperature could produce 50 to 90°C of generating temperature for the fluid refrigerant. This range of generating temperature yielded an evaporating temperature of 8 to 25 °C at a fixed condensing temperature of 40 °C. After numerical analyses, the determined coefficient of performance was at the range of 0.21 to 0.39, while nozzle and ejector efficiencies were from 94% to 99%. The geometric profiles of the ejector were also projected along with the varying generating temperature for both fluids. From the calculation, ammonia offers higher performance and efficiencies and lower evaporating temperatures suitable for larger cooling needs.

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Numerical evaluation of building heating potential from a co-axial closed-loop geothermal system using wellbore–reservoir coupling numerical model

Energy Exploration & Exploitation ◽

10.1177/0144598719889799 ◽

2019 ◽

Vol 38 (3) ◽

pp. 733-754 ◽

Cited By ~ 1

Author(s):

Tianfu Xu ◽

Zixu Hu ◽

Bo Feng ◽

Guanhong Feng ◽

Fengyu Li ◽

...

Keyword(s):

Geothermal Energy ◽

Closed Loop ◽

Heating System ◽

Coupling Model ◽

Production Performance ◽

Heat Extraction ◽

Geothermal System ◽

Renewable Energy Resources ◽

Practical Engineering ◽

System Maintenance

Geothermal energy is one of the most potential renewable energy resources. How to efficiently extract and utilize geothermal energy has been a worldwide hot topic. Co-axial closed-loop geothermal system is a novel method using a continuously closed wellbore without water exchange with. It is more suitable for reservoirs with medium or low temperature and permeability because many problems could be avoided such as lack of in situ groundwater or low infectivity of the reservoir. Many companies and research institutes have applied closed-loop geothermal system in building heating engineering and some fine results have been gained. However, in practical engineering construction, the area of a closed-loop geothermal system heating system is a very important parameter. It directly determines the cost accounting and initial design of the project. Accurate and reliable estimation of heating capacity becomes very important. In this study, a wellbore–reservoir coupling model is established, which is calibrated using measured data from a short-term field trial operation. We have carried out mixed convective–conductive fluid-flow modeling using a wellbore flow model for TOUGH2 called T2Well to investigate the heat extraction performance of closed-loop geothermal system. The system evolution and the effect of flow rate and injection temperature on heat production performance are discussed. The result shows that the intermittent production cycles are more beneficial for heat extraction and system maintenance, and the temperature recovery between two heating seasons is enough to maintain system heating. And we can calculate that a geothermal well can ensure heating of buildings of 10,000–20,000 m2 and the heating area of intermittent operation is 4000 m2 more than continuous operation. Besides, the sensitivity analysis of parameters is also carried out.

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Numerical Study of Natural Convection Heat Loss from Cylindrical Solar Cavity Receivers

ISRN Renewable Energy ◽

10.1155/2014/104686 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 11

Author(s):

M. Prakash

Keyword(s):

Natural Convection ◽

Cylindrical Cavity ◽

Numerical Study ◽

Three Dimensional ◽

Working Fluid ◽

Helical Coil ◽

Fluid Temperature ◽

Medium Temperature ◽

Inclination Angles ◽

Temperature Levels

The numerical study of the natural convection loss occurring from cylindrical solar cavity receivers is reported in this communication. These cavity receivers can be used with solar dish concentrators for process heat applications at medium temperature levels. Three cylindrical cavity receivers of diameter 0.2, 0.3, and 0.4 m with aspect ratio equal to one and opening ratios of 1 and 0.5 are used for the analysis. Fluent CFD software is used for the analysis of the three-dimensional (3D) receiver models. In this study the receiver tubes within the cylindrical cavity are modeled as a helical coil similar to those existing in actual systems. The flow of the working fluid within the helical coil is also modeled. The simulations are performed for fluid inlet temperatures of 150°C and 250°C and for receiver inclination angles of 0 (sideways-facing cavity), 30, 45, 60, and 90 degree (vertically downward-facing receiver). It is found that the convective loss increases with increasing mean fluid temperature and decreases with, increase in receiver inclination. The convective loss is found to increase with, opening ratio. These observations are true for all cavity receivers analysed here. A Nusselt number correlation involving Rayleigh numbers, receiver inclinations, and opening ratios is proposed for the convective loss.

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Geothermal energy development by circulating CO2 in a U-shaped closed loop geothermal system

Energy Conversion and Management ◽

10.1016/j.enconman.2018.08.094 ◽

2018 ◽

Vol 174 ◽

pp. 971-982 ◽

Cited By ~ 59

Author(s):

Fengrui Sun ◽

Yuedong Yao ◽

Guozhen Li ◽

Xiangfang Li

Keyword(s):

Geothermal Energy ◽

Closed Loop ◽

Energy Development ◽

Geothermal System

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The Utilization of Abandoned Petroleum Wells in Geothermal Energy Sector. Worldwide Trends and Experience

E3S Web of Conferences ◽

10.1051/e3sconf/202015405004 ◽

2020 ◽

Vol 154 ◽

pp. 05004

Author(s):

Anna Chmielowska ◽

Barbara Tomaszewska ◽

Anna Sowiżdżał

Keyword(s):

Geothermal Energy ◽

Oil And Gas ◽

Electricity Production ◽

Successful Implementation ◽

Geothermal Resources ◽

Tremendous Amount ◽

Exploratory Wells ◽

Petroleum Wells ◽

The Cost ◽

Oil Crises

Since the oil crises in the 1970s, geothermal resources have received much attention and researches aimed at its recognition have been conducted all around the globe. Nevertheless, the investment cost associated mainly with drilling works is a crucial limitation for the successful implementation of new geothermal projects. The radical solution affecting the cost effectiveness of any geothermal investments might be an adaptation of existing un-exploited boreholes of the oil and gas sector for geothermal purposes. Moreover, a few studies on heat and/or energy recovery from oil and gas provinces have indicated that a tremendous amount of geothermal energy co-exists with petroleum fields. Thereby, the article centres on global concepts related to the adaptation of boreholes after the exploitation of hydrocarbon deposits or negative exploratory wells in order to exploit geothermal energy resources. Selected concepts focused on possible electricity production and the space heating sector are discussed. Other potential technologies based on utilization of geothermal energy attained by borehole heat exchangers are also indicated.

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Revitalization of abandoned oil and gas wells for a geothermal heat exploitation by means of closed circulation: Case study of the deep dry well Pčelić-1

Interpretation ◽

10.1190/int-2017-0079.1 ◽

2018 ◽

Vol 6 (1) ◽

pp. SB1-SB9 ◽

Cited By ~ 8

Author(s):

Marija Macenić ◽

Tomislav Kurevija

Keyword(s):

Steady State ◽

Geothermal Energy ◽

Heat Load ◽

Oil And Gas ◽

Pannonian Basin ◽

Heat Extraction ◽

Fluid Temperature ◽

Gas Wells ◽

Oil And Gas Wells

The aim of our research is to use abandoned deep-hydrocarbon reservoirs and dry wells in the Croatian part of the Pannonian Basin as a geothermal energy source. Croatia has been exploring and exploiting hydrocarbon reserves in the Pannonian Basin from the mid-20th century. Therefore, many oil and gas wells are reaching the end of their production phase and many are already abandoned. These wells could be considered for geothermal energy production through the coaxial heat exchanger principle, which is usually used in shallow geothermal energy extraction. Using the abandoned deep well Pčelić located in the Drava subbasin as a case study, we have derived the available energy and fluid temperature changes during 20 years of operation for two cases: one with a constant base heat load throughout the year and the second as a variable heat load depending on outside air temperatures. We determined that the maximum potential heat extraction in a variable system is 1750 MWh per year, with 1.5 MW of peak heating power in winter, depending on the sink temperature, climate, and consumer input data. The maximum theoretical constant heat extraction for possible industrial direct heating could be 400 kW during the entire period of 20 years, with fluid temperature reaching steady state at a favorable 50°C. To define steady-state ratio between extracted heat and consumed energy at the circulating pump, we evaluated seasonal performance factor (SPF) analysis similar to heat pump systems. Lower values of SPF linked to a higher flow rate implies higher energy extraction. Our results show that when using a lower flow, steady-state SPF ratio is as high as 280, and for a higher flow, steady-state SPF ratio drops to only 25.

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