Determination of Rock Thermal Conductivity Under in-Situ Conditions: Experimental and Numerical Investigation

EasyChair Preprint 3476

Abstract

In this study, the effects of pressure and temperature on thermal conductivity of natural mono-minerals rocks in in-situ condition is investigated. Heat transfer in rock masses is one of the most critical crucial processes that needs to be considered in subsurface engineering applications, such as radioactive waste repositories, geothermal energy, and oil and gas storages. Despite the need, there is no direct method for measuring the change of thermal conductivity under high pressure and temperature loadings similar to what is found in in-situ condition. Therefore, in this study the  thermal conductivity of 5 mono-mineral rock samples (Anhydrit, Mormor, Quarzit, Gips, Obsidan/perlit) under in-situ conditions are determined during a steady state and while using a reference material for direct measurement of thermal conductivity. The measurements are made over a temperature and hydrostatic pressure range of room temperature to 400 °C and 12 MPa to 400 MPa, respectively. The results indicate that the thermal conductivity of all samples increase with increasing pressure. The non-linear increase of thermal conductivity is found for rock samples at low hydrostatic pressure below 100 MPa. Additionally, the effect of micro-structure and mineralogical composition on thermal conductivity of mono-minerals rocks is discussed. The test results constitute the first systematic measurement of thermal conductivity on in-situ condition of different type of rocks and can be further used for the development of thermal models for predicting the thermal responses.

Keyphrases: in-situ conditions, mono-minerals, rocks, thermal conductivity

@booklet{EasyChair:3476,
  author    = {Hem Bahadur Motra and Frederick Sittig and Dennis Schwindrofska and Amir Shoarian Sattari and Frank Wuttke},
  title     = {Determination of Rock Thermal Conductivity Under in-Situ Conditions: Experimental and Numerical Investigation},
  howpublished = {EasyChair Preprint 3476},
  year      = {EasyChair, 2020}}