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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS017 Poster presentation 2392
Studying thermal properties of sedimentary and crystalline rocks at
elevated temperature and pressures: equipment, methodology and results
Mr. Dmitriy Miklashevskiy
Technical Physics and Rock Physics Russian State Geological Prospecting University IASPEI
Yuri Popov, Vladimir Tertychnyi, Irina Bayuk, Raisa Romushkevich, Christof
Clauser, Renate Pechnig
Rocks thermal properties - thermal conductivity (TC), thermal diffusivity (TD) and volumetric heat
capacity (VHC) - have been studied using a newly developed instrument which allows the
measurements with simultaneous influence of temperature, pore and two components of lithostatic
pressures. A special methodology has been elaborated to study rock matrix properties and pore space
geometry before and after the measurements at elevated temperature and pressure. The methodology
provides a control of changes in inner pore structure and matrix thermal properties during PT
measurements and is based on (1) experimental results on thermal conductivity, thermal diffusivity and
volumetric heat capacity of rocks at normal conditions using the precise optical scanning instrument; (2)
estimation of inner pore space structure and matrix thermal properties with theoretical modeling. Two
rock collections have been studied. Collection 1: 59 sedimentary rocks included feldspar-quartz and
quartz feldspar-sandstone samples, carbonate and sulphate rocks. Porosity values varied within a range
of (0.236)%. According to the results of thermal property measurements at elevated temperature
(25180) oC and equal vertical and horizontal components of lithostatic pressure (up to 180 MPa) and
pore pressure (up to 80 MPa) TC, TD and VHC have varied at pressure of 180 MPa and temperature of
120 oC by -9.246%, -64-14% and 0.9171%, respectively. Variations of TC bersus PT conditions are
close to linear low.Correlation between slope angle of TC(P,T) curves and TC values at normal PT
conditions has been found to be close for sandstones and carbonate rocks with correlation coefficients -
0.81 and -0.91, correspondingly. Collection 2: 19 cores from the Ural superdeep well SG-3 (Russia) were
sampled within depth interval of (6505939) m. Porosity of the studied rocks varied within range of
(0.11.5)%. Results of thermal property measurements at elevated temperature (25120) oC and equal
vertical and horizontal components of lithostatic pressure have shown that thermal conductivity, thermal
diffusivity and volumetric heat capacity vary at pressure of 170 MPa and temperature of 120 oC by -5.9-
26 %, -11.2-33% and 2.732%, respectively. Decrease in TC values for PT conditions corresponding to
the sampling depths has been found to be equal to 4% in average in comparison to TC values at normal
conditions that allows correction of previous estimates of heat flow density done with thermal
conductivity values obtained from the measurements at normal conditions. Authors wish to
acknowledge generous support of Schlumberger Oilfield Services, an international company in oil and
gas industry, and Russian Foundation for Basic Research (grant 05-05-64879).
Keywords: measurements, thermal, properties