Determining the relationship of thermal conductivity and compressional wave velocity of common rock types as a basis for reservoir characterization

Mielke, Philipp; Bär, Kristian; Sass, Ingo

doi:10.1016/j.jappgeo.2017.04.002

Cited by 70 publications

(45 citation statements)

References 46 publications

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“…The thermal conductivity of the rocks depends not only on mineralogical composition and microstructure (porosity, fracture density, texture), but also on pressure, rock temperature and degree of saturation and nature of the fluid. The effect of those parameters on thermal conductivity have been largely investigated by previous studies, which showed that the thermal conductivity of rocks generally decreases with increasing porosity (Woodside and Messmer 1961;Popov et al 2003;Nagaraju and Roy 2014;Guo et al 2017;Mielke et al 2017), whereas pressure tends to reduce porosity, close (micro)cracks and improve heat transport at grain-grain contacts and, thus, increase thermal conductivity (Walsh and Decker 1966;Abdulagatova et al 2009;Schön and Dasgupta 2015). On the contrary, high temperature tends to decrease the thermal conductivity of rocks due to differential thermal expansion of the minerals, which may increase contact resistances between the grains and result in thermal cracking creating porosity (Vosteen and Schellschmidt 2003;Abdulagatov et al 2006;Abdulagatova et al 2009;Guo et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Heat flow density estimates in the Upper Rhine Graben using laboratory measurements of thermal conductivity on sedimentary rocks

et al. 2019

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The Upper Rhine Graben (URG) has been extensively studied for geothermal exploitation over the past decades. Yet, the thermal conductivity of the sedimentary cover is still poorly constrained, limiting our ability to provide robust heat flow density estimates. To improve our understanding of heat flow density in the URG, we present a new large thermal conductivity database for sedimentary rocks collected at outcrops in the area including measurements on (1) dry rocks at ambient temperature (dry); (2) dry rocks at high temperature (hot) and (3) water-saturated rocks at ambient temperature (wet). These measurements, covering the various lithologies composing the sedimentary sequence, are associated with equilibrium-temperature profiles measured in the Soultz-sous-Forêts wells and in the GRT-1 borehole (Rittershoffen) (all in France). Heat flow density values considering the various experimental thermal conductivity conditions were obtained for different depth intervals in the wells along with average values for the whole boreholes. The results agree with the previous heat flow density estimates based on dry rocks but more importantly highlight that accounting for the effect of temperature and water saturation of the formations is crucial to providing accurate heat flow density estimates in a sedimentary basin. For Soultz-sous-Forêts, we calculate average conductive heat flow density to be 127 mW/m 2 when considering hot rocks and 184 mW/m 2 for wet rocks. Heat flow density in the GRT-1 well is estimated at 109 and 164 mW/m 2 for hot and wet rocks, respectively. Results from the Rittershoffen well suggest that heat flow density is nearly constant with depth, contrary to the observations for the Soultz-sous-Forêts site. Our results show a positive heat flow density anomaly in the Jurassic formations, which could be explained by a combined effect of a higher radiogenic heat production in the Jurassic sediments and thermal disturbance caused by the presence of the major faults close to the Soultz-sous-Forêts geothermal site. Although additional data are required to improve these estimates and our understanding of the thermal processes, we consider the heat flow densities estimated herein as the most reliable currently available for the URG.

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Section: Introductionmentioning

confidence: 99%

Heat flow density estimates in the Upper Rhine Graben using laboratory measurements of thermal conductivity on sedimentary rocks

et al. 2019

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“…This will extend the opportunity to also use the database to derive phenomenological constitutive models for petrophysical rock properties from their chemical or mineralogical composition (Chopra et al, 2018, Gard et al, 2019 or from their microstructure (Pimienta et al, 2014) or to develop empirical correlations between distinct properties of certain rock types (Gegenhuber and Schön, 2012, Esteban et al, 2015, Mielke et al, 2017.…”

Section: Discussionmentioning

confidence: 99%

P<sup>3</sup> – PetroPhysical Property Database – a global compilation of lab measured rock properties

Bär

Reinsch

Sippel

2020

Preprint

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Abstract. Petrophysical properties are key to populate local and/or regional numerical models and to interpret results from geophysical investigation methods. Searching for rock property values measured on samples from a specific rock unit at a specific location might become a very time-consuming challenge given that such data are spread across diverse compilations and that the number of publications on new measurements is continuously growing and data are of heterogeneous quality. Profiting from existing laboratory data to populate numerical models or interpret geophysical surveys at specific locations or for individual reservoir units is often hampered if information on the sample location, petrography, stratigraphy, measuring method and conditions are sparse or not documented. Within the framework of the EC funded project IMAGE (Integrated Methods for Advanced Geothermal Exploration, EU grant agreement No. 608553), an open-access database of lab measured petrophysical properties has been developed (Bär et al., 20182019: P3 – Database, https://doi.org/10.5880/GFZ.4.8.2019.P3). The goal of this hierarchical database is to provide easily accessible information on physical rock properties relevant for geothermal exploration and reservoir characterization in a single compilation. Collected data include classical petrophysical, thermophysical and mechanical properties and, in addition, electrical conductivity and magnetic susceptibility. Each measured value is complemented by relevant meta-information such as the corresponding sample location, petrographic description, chronostratigraphic age, if available, and original citation. The original stratigraphic and petrographic descriptions are transferred to standardized catalogues following a hierarchical structure ensuring inter-comparability for statistical analysis (Bär et al., 2019: P3 – Petrography, https://doi.org/10.5880/GFZ.4.8.2019.P3.p, Bär et al., 20182019: 3 – Stratigraphy, https://doi.org/10.5880/GFZ.4.8.2019.P3.s. In addition, information on the experimental setup (methods) and the measurement conditions are listed for quality control. Thus, rock properties can directly be related to in-situ conditions to derive specific parameters relevant for simulating subsurface processes or interpreting geophysical data. We describe the structure, content and status quo of the database and discuss its limitations and advantages for the end-user.

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“…Whenever possible, all parameters were measured on each plug or rock sample for direct correlation. The rock samples were classified after Norini et al (2015) and Avellán et al (2017) into (1) Post-caldera volcanism, (2) Caldera volcanism, (3) Pre-caldera volcanism and (4) Basement and Intrusive rocks.…”

Section: Methodsmentioning

confidence: 99%

“…Proceq device along different directions on the sample surfaces in order to identify anisotropy and the effect of fractures. The combined measurement of both P-and S-wave velocity offers the opportunity to retrieve elastic mechanical parameters like Poisson ratio, Young's modulus and G modulus (Mielke et al, 2017).…”

Section: Methodsmentioning

confidence: 99%

Outcrop analogue study to determine reservoir properties of the Los Humeros and Acoculco geothermal fields, Mexico

et al. 2018

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Abstract. The Los Humeros geothermal system is steam dominated and currently under exploration with 65 wells (23 producing). Having temperatures above 380 ∘C, the system is characterized as a super hot geothermal system (SHGS). The development of such systems is still challenging due to the high temperatures and aggressive reservoir fluids which lead to corrosion and scaling problems. The geothermal system in Acoculco (Puebla, Mexico; so far only explored via two exploration wells) is characterized by temperatures of approximately 300 ∘C at a depth of about 2 km. In both wells no geothermal fluids were found, even though a well-developed fracture network exists. Therefore, it is planned to develop an enhanced geothermal system (EGS). For better reservoir understanding and prospective modeling, extensive geological, geochemical, geophysical and technical investigations are performed within the scope of the GEMex project. Outcrop analogue studies have been carried out in order to identify the main fracture pattern, geometry and distribution of geological units in the area and to characterize all key units from the basement to the cap rock regarding petro- and thermo-physical rock properties and mineralogy. Ongoing investigations aim to identify geological and structural heterogeneities on different scales to enable a more reliable prediction of reservoir properties. Beside geological investigations, physical properties of the reservoir fluids are determined to improve the understanding of the hydrochemical processes in the reservoir and the fluid-rock interactions, which affect the reservoir rock properties.

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Determining the relationship of thermal conductivity and compressional wave velocity of common rock types as a basis for reservoir characterization

Cited by 70 publications

References 46 publications

Heat flow density estimates in the Upper Rhine Graben using laboratory measurements of thermal conductivity on sedimentary rocks

Heat flow density estimates in the Upper Rhine Graben using laboratory measurements of thermal conductivity on sedimentary rocks

P<sup>3</sup> – PetroPhysical Property Database – a global compilation of lab measured rock properties

Outcrop analogue study to determine reservoir properties of the Los Humeros and Acoculco geothermal fields, Mexico

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Determining the relationship of thermal conductivity and compressional wave velocity of common rock types as a basis for reservoir characterization

Cited by 70 publications

References 46 publications

Heat flow density estimates in the Upper Rhine Graben using laboratory measurements of thermal conductivity on sedimentary rocks

Heat flow density estimates in the Upper Rhine Graben using laboratory measurements of thermal conductivity on sedimentary rocks

P&lt;sup&gt;3&lt;/sup&gt; – PetroPhysical Property Database – a global compilation of lab measured rock properties

Outcrop analogue study to determine reservoir properties of the Los Humeros and Acoculco geothermal fields, Mexico

Contact Info

Product

Resources

About

P<sup>3</sup> – PetroPhysical Property Database – a global compilation of lab measured rock properties