Improving thermal response tests with wireline temperature logs to evaluate ground thermal conductivity profiles and groundwater fluxes

Pambou, Claude Hugo Koubikana; Raymond, Jasmin; Lamarche, Louis

doi:10.1007/s00231-018-2532-y

Cited by 11 publications

(32 citation statements)

References 25 publications

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“…From previous TRT and slug tests carried out at the same site, bulk TC of the shales is 1.7-1.8 W m −1 K −1 and hydraulic conductivity of the highlighted fracture zones is 10 −8 m s −1 . Darcy flux was estimated to 1 to 4 × 10 −9 m s −1 , and Darcy velocity to 10 −10 m s −1 [25][26][27]. Koubikana Pambou et al [27] showed that GW does affect the subsurface TC inferred from TRT in correspondance of the fracture zones, with effective TC reaching maximum values of 2.0 W m −1 K −1 .…”

Section: Description Of the Test Sitementioning

confidence: 99%

“…Darcy flux was estimated to 1 to 4 × 10 −9 m s −1 , and Darcy velocity to 10 −10 m s −1 [25][26][27]. Koubikana Pambou et al [27] showed that GW does affect the subsurface TC inferred from TRT in correspondance of the fracture zones, with effective TC reaching maximum values of 2.0 W m −1 K −1 . However, this influence appears to be local and limited to fracture zones with thickness of few meters.…”

Section: Description Of the Test Sitementioning

confidence: 99%

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Evaluation of Subsurface Heat Capacity through Oscillatory Thermal Response Tests

2021

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Two methods are currently available to estimate in a relatively short time span the subsurface heat capacity: (1) laboratory analysis of rock/soil samples; (2) measure the heat diffusion with temperature sensors in an observation well. Since the first may not be representative of in-situ conditions, and the second imply economical and logistical issues, a third option might be possible by means of so-called oscillatory thermal response tests (OTRT). The aim of the study was to evaluate the effectiveness of an OTRT as a tool to infer the subsurface heat capacity without the need of an observation well. To achieve this goal, an OTRT was carried out in a borehole heat exchanger (BHE). The total duration of injection was 6 days, with oscillation period of 12 h and amplitude of 10 W m−1. The results of the proposed methodology were compared 3-D numerical simulations and to a TRT with a constant heat injection rate with temperature response monitored from a nearby observation well. Results show that the OTRT succeeded to infer the expected subsurface heat capacity, but uncertainty is about 15% and the radial depth of penetration is only 12 cm. The parameters having most impact on the results are the subsurface thermal conductivity and the borehole thermal resistance. The OTRT performed and analyzed in this study also allowed to evaluate the thermal conductivity with similar accuracy compared to conventional TRTs (3%). On the other hand, it returned borehole thermal resistance with high uncertainty (15%), in particular due to the duration of the test. The final range of heat capacity is wide, highlighting challenges to currently use OTRT in the scope of ground-coupled heat pump system design. OTRT appears a promising tool to evaluate the heat capacity, but more field testing and mathematical interpretation of the sinusoidal response is needed to better isolate the subsurface from the BHE contribution and reduce the uncertainty.

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Section: Description Of the Test Sitementioning

confidence: 99%

Section: Description Of the Test Sitementioning

confidence: 99%

Evaluation of Subsurface Heat Capacity through Oscillatory Thermal Response Tests

2021

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“…The results of Pambou et al [28] did not exceed values of around 55 W/m and a temperature increase of 1-2 degrees by applying a relative high heat injection rate due to the system length. Although, a similar heat load was applied, for instance around 1500 W [24], the reached temperatures were distinctly lower than within this study (inlet temperature ≈ 50 • C) due to the system depth.…”

Section: Discussionmentioning

confidence: 78%

“…There is the potential to use the measured temperature profiles to determine other parameters, such as the borehole thermal resistance [25][26][27]. Additionally, a Darcy flow analysis or a Péclet number analysis could be performed by interpreting the temperature logs [28]. The derivation of these hydraulic quantities may also support the idea of differentiating between areas in which heat is primarily transferred by conduction and those in which the convection dominates, as introduced in [14].…”

Section: Discussionmentioning

confidence: 99%

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A Case Study of Thermal Evolution in the Vicinity of Geothermal Probes Following a Distributed TRT Method

et al. 2021

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To meet the stated climate change targets and to ensure the capability of meeting the current and future energy demands, there is an urgent need to develop renewable energy sources, such as geothermal systems. If geothermal systems are to be cost-efficient and are to enjoy public confidence, it is essential that they are designed and installed in accordance with the prevailing site-specific conditions. A thorough understanding of the thermal behaviour of the surrounding ground is, therefore, critical. In this work, we investigated temperature and its evolution in the vicinity of a shallow geothermal helix-shaped borehole heat exchanger (BHE). To measure the temperature close to the actual geothermal system, an additional U-tube probe was installed at the edge of the same borehole. A thermal load was then applied to the BHE, and the temperature was detected in the nearby U-tube. The temperature measurements were made with a GEOSniff monitoring device. To understand these localised temperature measurements in the context of the Valencia test site, ERT measurements were also performed. The GEOSniff device permits measurements to be made with very high depth resolution, which allows the thermal properties of the surrounding ground to be derived precisely, thus, enabling the identification of the different textural domains.

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Thermal Response Tests (TRT)

Lamarche

2023

Fundamentals of Geothermal Heat Pump Systems

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Improving thermal response tests with wireline temperature logs to evaluate ground thermal conductivity profiles and groundwater fluxes

Cited by 11 publications

References 25 publications

Evaluation of Subsurface Heat Capacity through Oscillatory Thermal Response Tests

Evaluation of Subsurface Heat Capacity through Oscillatory Thermal Response Tests

A Case Study of Thermal Evolution in the Vicinity of Geothermal Probes Following a Distributed TRT Method

Thermal Response Tests (TRT)

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