Dipole and Convergent Single-Well Thermal Tracer Tests for Characterizing the Effect of Flow Configuration on Thermal Recovery

Experimental characterization of thermal transport in fractured media through thermal tracer tests is crucial for environmental and industrial applications such as the prediction of geothermal system efficiency. However, such experiments have been poorly achieved in fractured rock due to the low permeability and complexity of these media. We have thus little knowledge about the effect of flow configuration on thermal recovery during thermal tracer tests in such systems. We present here the experimental set up and results of several single-well thermal tracer tests for different flow configurations, from fully convergent to perfect dipole, achieved in a fractured crystalline rock aquifer at the experimental site of Plœmeur (H+ observatory network). The monitoring of temperature using Fiber-Optic Distributed Temperature Sensing (FO-DTS) associated with appropriate data processing allowed to properly highlight the heat inflow in the borehole and to estimate temperature breakthroughs for the different tests. Results show that thermal recovery is mainly controlled by advection processes in convergent flow configuration while in perfect dipole flow field, thermal exchanges with the rock matrix are more important, inducing lower thermal recovery.

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Time-lapse monitoring of fractured rock response to hydraulic stimulation using pressure tomography

10.5194/egusphere-egu2020-6751 ◽

2020 ◽

Author(s):

Márk Somogyvári ◽

Mohammadreza Jalali

Keyword(s):

Dynamic Response ◽

Fractured Rock ◽

Fluid Pressure ◽

Time Lapse ◽

Fracture Network ◽

Industrial Applications ◽

Geothermal System ◽

Fractured Reservoir ◽

Hydraulic Stimulation ◽

The Individual

Hydraulic stimulation using high-pressure fluid injection has become the common technique for rock mass treatment in various industrial applications such oil & gas, mining and enhanced geothermal system (EGS) development. Hydraulic stimulation is associated with creation of new fractures or dilation of existing fractures that could alter the flow regime in the stimulated reservoir. In this context, it would be beneficiary to understand the dynamic response of the discrete fracture network (DFN) to the stimulation activities rather than comparison between the changes in injectivity and/or transmissivity.In this work, a 2-D fully coupled hydro-mechanical model is developed to simulate the dynamic response of a fractured reservoir to hydraulic stimulation. The model calculates stresses, fracture fluid pressure and flow inside the fractures, and modifies the physical properties of the individual fractures given these values. All these alterations will be calculated and applied after each simulation timestep. The results of this synthetic modelling will be used to test the time-lapse pressure tomography approach.Pressure tomography will be simulated at multiple timesteps, to capture the hydraulically active fractures within the system. The used tomographic interpretation will be based on the transdimensional DFN inversion, where model parametrization could change over time. With this methodology we can model the newly opened fractures by the stimulation.The time-lapse inversion will use the result of the previous timestep as the initial solution for improved efficiency. We test the proposed methodology on outcrop based synthetic 2-D DFN models. The results could capture the changes of permeability (i.e. aperture) as a direct response to hydraulic stimulation.

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Bacterial Transport in Fractured Rock – A Field-Scale Tracer Test at the Chalk River Nuclear Laboratories

Water Science & Technology ◽

10.2166/wst.1988.0269 ◽

1988 ◽

Vol 20 (11-12) ◽

pp. 81-87 ◽

Cited By ~ 63

Author(s):

D. R. Champ ◽

J. Schroeter

Keyword(s):

Water Movement ◽

Fractured Rock ◽

Tracer Tests ◽

Crystalline Rock ◽

Tracer Test ◽

Breakthrough Curves ◽

Water Recovery ◽

Field Scale ◽

Particulate Contaminants ◽

Conservative Tracers

The potential for transport of bacteria by groundwater in fractured crystalline rock was assessed in a series of field-scale tracer tests. The breakthrough curves for injected Escherichla coll and “non-reactive” particle tracers were compared with those for conservative inorganic and radioactive tracers. Rapid transport, relative to the conservative tracers, of both bacteria and non-reactive particles was observed. The first appearance of both was with, or slightly before, the conservative tracers for water movement. Removal of the bacteria and particles by filtration processes occurred and was quantified through the calculation of filter factors. The filtration process in this fracture system is similar to that found in a gravel aquifer. From the results we can conclude that particulate contaminants can be very rapidly transported in fracture systems and that continuing sources of contamination could lead to relatively high local concentrations of particulate contaminants compared with the average at any given distance from the source. It was also concluded that the use of traditional conservative tracers, for water movement, to assess the potential for movement of particulate contaminants could lead to significant underestimates of exposure to particulate contaminants due to consumption of water from water recovery wells located in fractured media.

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A Novel Conceptual Model for the Flow and Transport in Fractured Rock

MRS Proceedings ◽

10.1557/proc-212-831 ◽

1990 ◽

Vol 212 ◽

Author(s):

V. Taivassalo ◽

A. Hautojärvi

Keyword(s):

Field Experiments ◽

Molecular Diffusion ◽

Transport Model ◽

Fractured Rock ◽

Tracer Tests ◽

Crystalline Rock ◽

Research Area ◽

Fracture Plane ◽

Fracture Aperture ◽

Test Case

ABSTRACTIn crystalline rock groundwater flows predominantly in fractures and fissures. Strongly varying fracture aperture guides the flow preferentially in some parts of a fracture plane, in so called channels. In our hydraulic model the degree of channeling together with the aperture variation along a channel is included as a factor which is the ratio of the aperture from transmissivity measurements and the aperture from the tracer tests.The developed transport model takes into account the coupling of molecular diffusion and advection in a velocity field varying linearly over a characteristic width. Various flow velocities in different parts of a channel cause a transient phase with non-Fickian behavior of dispersion. This might erroneously be attributed to other processes e.g. matrix diffusion when not taken into account in the migration modeling of tracers. Molecular diffusion across the flow field, however, tends to smooth out the transport time differences. With time the dispersion diminishes and becomes more symmetric in confined channels.The concept and models have been applied to predict and interpret field experiments aimed to investigate transport over long distances in highly conductive fracture zones. The analyzed experiments have been performed at the Finnsjön research area in Sweden and they belong to the test case 5 of the INTRAVAL project.

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The effects of hydro-mechanical coupling on hydraulic properties of fractured rock mass in unidirectional and radial flow configurations

Geomechanics and Geophysics for Geo-Energy and Geo-Resources ◽

10.1007/s40948-021-00286-x ◽

2021 ◽

Vol 7 (3) ◽

Author(s):

Wei Li ◽

Zhechao Wang ◽

Liping Qiao ◽

Jie Liu ◽

Jinjin Yang

Keyword(s):

Rock Mass ◽

Hydraulic Properties ◽

Radial Flow ◽

Fractured Rock ◽

Fractured Rock Mass ◽

Mechanical Coupling ◽

Flow Configurations

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Performance of Hybrid Single Well Enhanced Geothermal System and Solar Energy for Buildings Heating

Energies ◽

10.3390/en13102473 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2473

Author(s):

Yujiang He ◽

Xianbiao Bu

Keyword(s):

Solar Energy ◽

Service Life ◽

Heating System ◽

Hydrothermal Systems ◽

Geothermal System ◽

Heat Output ◽

Enhanced Geothermal System ◽

Geothermal Heat ◽

Hybrid Heating ◽

Single Well

The energy reserves in hot dry rock and hydrothermal systems are abundant in China, however, the developed resources are far below the potential estimates due to immature technology of enhanced geothermal system (EGS) and scattered resources of hydrothermal systems. To circumvent these problems and reduce the thermal resistance of rocks, here a shallow depth enhanced geothermal system (SDEGS) is proposed, which can be implemented by fracturing the hydrothermal system. We find that, the service life for SDEGS is 14 years with heat output of 4521.1 kW. To extend service life, the hybrid SDEGS and solar energy heating system is proposed with 10,000 m2 solar collectors installed to store heat into geothermal reservoir. The service life of the hybrid heating system is 35 years with geothermal heat output of 4653.78 kW. The novelty of the present work is that the hybrid heating system can solve the unstable and discontinuous problems of solar energy without building additional back-up sources or seasonal storage equipment, and the geothermal thermal output can be adjusted easily to meet the demand of building thermal loads varying with outside temperature.

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Expanding the Envelope of Fiber-Optic Sensing for Reservoir Description and Dynamics

10.2118/200888-ms ◽

2021 ◽

Author(s):

Abdulaziz Al-Qasim ◽

Sharidah Alabduh ◽

Muhannad Alabdullateef ◽

Mutaz Alsubhi

Keyword(s):

Performance Optimization ◽

Fiber Optic ◽

Thermal Recovery ◽

Production Performance ◽

Flow Profile ◽

Distributed Temperature Sensing ◽

Integrity Monitoring ◽

Well Integrity ◽

Fiber Optic Sensing ◽

Reservoir Description

Abstract Fiber-optic sensing (FOS) technology is gradually becoming a pervasive tool in the monitoring and surveillance toolkit for reservoir engineers. Traditionally, sensing with fiber optic technology in the form of distributed temperature sensing (DTS) or distributed acoustic sensing (DAS), and most recently distributed strain sensing (DSS), distributed flow sensing (DFS) and distributed pressure sensing (DPS) were done with the fiber being permanently clamped either behind the casing or production tubing. Distributed chemical sensing (DCS) is still in the development phase. The emergence of the composite carbon-rod (CCR) system that can be easily deployed in and out of a well, similar to wireline logging, has opened up a vista of possibilities to obtain many FOS measurements in any well without prior fiber-optic installation. Currently, combinations of distributed FOS data are being used for injection management, well integrity monitoring, well stimulation and production performance optimization, thermal recovery management, etc. Is it possible to integrate many of the distributed FOS measurements in the CCR or a hybrid combination with wireline to obtain multiple measurements with one FOS cable? Each one of FOS has its own use to get certain data, or combination of FOS can be used to make a further interpretation. This paper reviews the state of the art of the FOS technology and the gamut of current different applications of FOS data in the oil and gas (upstream) industry. We present some results of traditional FOS measurements for well integrity monitoring, assessing production and injection flow profile, cross flow behind casing, etc. We propose some nontraditional applications of the technology and suggest a few ways through. Which the technology can be deployed for obtaining some key reservoir description and dynamics data for reservoir performance optimization.

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Geo-Thermo-Mechanical Modeling of Pre-Drilled Wellbores to Extract Geothermal Energy from Subsurface to Produce Cleaner Energy for United Arab Emirates

10.2118/207844-ms ◽

2021 ◽

Author(s):

Ubedullah Ansari ◽

Najeeb Anjum Soomro ◽

Farhan Ali Narejo ◽

Shafquat Ali Baloch ◽

Faiz Ali Talpur

Keyword(s):

High Temperature ◽

United Arab Emirates ◽

Mechanical Model ◽

Geothermal Energy ◽

Oil And Gas ◽

Middle Eastern ◽

Clean Energy ◽

Thermal Recovery ◽

Abandoned Wells ◽

Single Well

Abstract The middle eastern countries including United Arab Emirates (UAE) have enjoyed the energy production from hydrocarbon resource for a very long period. Indeed, now various countries in this region has shifted to alternative resources of power generation with cheaper and cleaner sources. Geothermal is the top of the list among those sources. Therefore, this study presents an ultimate model converting abandoned oil and gas wells into subsurface geothermal recovery points. Fundamentally, this study offers a geo-thermo-mechanical model of abandoned wellbore which can help in developing an optimistic geothermal energy not only from subsurface thermal reserve but also from abandoned casing and pipes installed in Wellbores. In this approach the source of heat is thermally active rock formations and the metallic pipes that are present in wellbores drilled through hot dry rocks. In the model the already drilled wells are incorporated as medium of heat flow in which water in injected and brought back to surface along with thermal impact. The results of this study revealed that, at the depth of 6000 m of high temperature wellbore the temperature is above 85°C and at this temperature the metallic casings further rise the reserve temperature thus the conversion of water into steam can be processed easily. Moreover, at high depths the stability of wellbore is also issue in high temperature formation, so mechanical model suggests that injection of water and conversion into steam in already cased wellbore can sustain up to 6 MPa stress at around 100C. Thus, the geo-thermo-mechanical model of wellbore will illustrate the possibility of converting water into steam and it will also reveal the average amount of heat that can be generated from a single well. henceforth, the thermal recovery from abandoned wells of UAE is best fit solution for clean energy. The abandoned wells are used as conduit to transport heat energy from subsurface by using water as transport medium, as water at surface temperature is injected in those wellbores and let thermal energy convert that water into steam. Later the steam is returned to surface and used as fuel in turbines or generators.

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