Modeling wellbore heat exchangers: Fully numerical to fully analytical solutions

Tang, Hewei; Xu, Bin; Hasan, A. Rashid; Sun, Zhuang; Killough, John

doi:10.1016/j.renene.2018.10.094

Cited by 39 publications

(27 citation statements)

References 29 publications

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“…While authors in (Falcone et al, 2018) used constant water properties, T2Well uses the pressure and temperature dependent thermophysical properties based on models suggested by the International Formulation Committee (IFC, 1967). As stated in (Sui et al, 2019;Tang et al, 2019), constant fluid properties seem to generate errors in the pressure losses calculation and heat produced in DBHEs. The produced water temperature and heat flux were underestimated for a DBHE of 6100m and overestimated by 11% in a DBHE of 3500m (Hu et al, 2020).…”

Section: T2well Numerical Validation Experimental Validationmentioning

confidence: 99%

“…Right -Well completion diagram of the DBHE interpreted from (Cladouhos et al, 2016). Both depict the casing and cement sections at appropriate elevations in T2Well/EOS1, interpreted from (Tang et al, 2019;Toth, 2015).…”

Section: Mathematical Modelmentioning

confidence: 99%

“…The modelled DBHE involves pumping cold fluid down the outer annulus, such that hot fluid rises to surface up the inner tubing via a thermosiphon effect (natural convection) or through the use of pumps (Tang et al, 2019). The DBHE design was previously modelled in the Villafortuna abandoned oil well in Italy , the KTB deep borehole project setting in Germany (Falcone et al, 2018) and the IDDP-1 well in Iceland (Renaud et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): Sensitivity Analysis on the Newberry Volcanic Setting

Doran

Renaud

Falcone

et al. 2020

Preprint

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Geothermal energy is a baseload resource that has the potential to contribute significantly to the transition to a low-carbon future. Alternative (unconventional) deep geothermal designs are thus needed to provide a secure and efficient energy supply. Current Enhanced Geothermal Systems (EGS) are under technical review as a result of the associated low recovery factors and risk of induced seismicity in connection with reservoir stimulation operations, and Supercritical EGS (SEGS) concepts are still under early research and development. The Newberry and Icelandic Deep Drilling Projects (NDDP and IDDP) aid these developments to drill deeper into very hot temperature zones. An in-depth sensitivity analysis was investigated considering a deep borehole closed-loop heat exchanger (DBHE) to overcome the current limitations of deep EGS. Using the DBHE, cold working fluid is pumped down in the outer annulus and rises to the surface via natural convection or is pumped up via an inner tubing. A T2Well/EOS1 model previously calibrated on an experimental DBHE in Hawaii was adapted to the current NWG 55-29 well at the Newberry volcano site in Central Oregon. A sensitivity analysis was carried out, including parameters such as: the working fluid mass flow rate, the casing and cement thermal properties and the wellbore radii dimensions. The results allow an assessment of key thermodynamics within the wellbore and provide an insight into how heat is lost/gained throughout the system. This analysis was performed under the assumption of sub-critical conditions. Requirements for further software development are briefly discussed, which would facilitate the modelling of unconventional geothermal wells in supercritical systems.

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Section: T2well Numerical Validation Experimental Validationmentioning

confidence: 99%

Section: Mathematical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): Sensitivity Analysis on the Newberry Volcanic Setting

Doran

Renaud

Falcone

et al. 2020

Preprint

View full text Add to dashboard Cite

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“…Analytical DBHE models have shown good performances for an optimization analysis but overestimate the pressures losses at low mass flow rate and underestimate them at higher mass flow rate, compared to numerical models [21]. Numerical methods have been established as the most accurate approach, notably for modelling early transient time processes [21].…”

Section: Introductionmentioning

confidence: 99%

“…Typically, constant water properties have been applied to estimate the heat transfer in DBHEs [10], but constant fluid properties are known to lead to errors in pressure losses calculations [21]. Density variations can have an impact on the thermosiphon-effect, as it compensates pressure losses due to density variations of the ascending and injecting working fluid [22], and surface pressure from the internal tubing can be higher than the pressure at the injection point.…”

Section: Introductionmentioning

confidence: 99%

Conjugated Numerical Approach for Modelling DBHE in High Geothermal Gradient Environments

2020

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Geothermal is a renewable energy source that can be untapped through various subsurface technologies. Closed geothermal well solutions, such as deep geothermal heat exchangers (DBHEs), consist of circulating a working fluid to recover the available heat, with less dependency on the local geological settings than conventional geothermal systems. This paper emphasizes a double numerical method to strengthen the assessment of DBHE performances. A computational fluid dynamics (CFD) commercial software and the 1D coupled wellbore-reservoir geothermal simulator T2Well have been used to investigate the heat transfer and fluid flow in a vertical DBHE in high geothermal gradient environments. The use of constant water properties to investigate the energy produced from DBHEs can lead to underestimating the overall heat transfer at high temperature and low mass flow rate. 2D axisymmetric CFD modelling improves the understanding of the return flow at the bottom of the DBHE, readjusting and better estimating the pressures losses commonly obtained with 1D modelling. This paper highlights the existence of convective cells located at the bottom of the DBHE internal tubing, with no significant effects due to the increase of injected water flow. Both codes are shown to constrain the numerical limitations to access the true potential of geothermal heat extraction from DBHEs in high geothermal gradient environments and demonstrate that they can be used for geothermal energy engineering applications.

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Development of a wellbore heat transfer model considering circulation loss

Wang

Liu

et al. 2020

Arab J Geosci

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Modeling wellbore heat exchangers: Fully numerical to fully analytical solutions

Cited by 39 publications

References 29 publications

Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): Sensitivity Analysis on the Newberry Volcanic Setting

Modelling an unconventional closed-loop deep borehole heat exchanger (DBHE): Sensitivity Analysis on the Newberry Volcanic Setting

Conjugated Numerical Approach for Modelling DBHE in High Geothermal Gradient Environments

Development of a wellbore heat transfer model considering circulation loss

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