Rocks thermal

Varying rock thermal conduction If there is one type of rock that is conducting more heat than the surrounding rock, the rock with greater heat conduction will stay warmer than the surrounding one. In such cases water would be trapped and overpressure would occur when freezing. 

Contact metamorphism takes place in small areas adjacent to a hot mass, like a chamber of molten rock. It can occur two ways, either through the heating of the surrounding rocks (thermal) or by a combination of heat and the injection of charged fluids from the igneous body (hydrothermal). Many ore deposits are formed hydrothermally. 

Figure 24 Chondrite-normalized abundances of REEs in a wall-rock harzburgite from Lherz (dotted lines— whole-rock analyses), compared with numerical experiments of ID porous melt flow, after Bodinier et al. (1990). The harzburgite samples were collected at 25-65 cm from an amphibole-pyroxenite dike. In contrast with the 0-25 cm wall-rock adjacent to the dike, they are devoid of amphibole but contain minute amounts of apatite (Woodland et al., 1996). The strong REE fractionation observed in these samples is explained by chromatographic fractionation due to diffusional exchange of the elements between peridotite minerals and advective interstitial melt (Navon and Stolper, 1987 Vasseur et al, 1991). The results are shown in (a) for variable t t ratio, where t is the duration of the infiltration process and t the time it takes for the melt to percolate throughout the percolation column (Navon and Stolper, 1987). This parameter is proportional to the average melt/rock ratio in the percolation column. In (b), the results are shown for constant f/fc but variable proportion of clinopyroxene at the scale of the studied peridotite slices (<5 cm). All model parameters may be found in Bodinier et al. (1990). As discussed in the text, this model was criticized by Nielson and Wilshire (1993). An improved version taking into account the gradual solidiflcation of melt down the wall-rock thermal gradient and the isotopic variations was recently proposed by Bodinier et al. (2003).

Vitrinite reflectance (Ro) Ro defines the source rock thermal maturity level. 

After a short initial period of applying increasing power to the heaters, a constant 100° C temperature has been applied to the contact between the heater and the buffer, in correspondence with the test protocol. Although the full heating test has lasted for five years, the analysis has been run up to 100 years to check and predict long term THMC conditions. The rock thermal, hydraulic and mechanical boundary conditions have been based on the results of the comprehensive site investigation carried out at the site. 

The above equation is the shear strength parameters of rock salt with temperature relationship which represented by the thermal damage factor. Thus, once the salt rock thermal damage factor variation with temperature is obtained, it can get different salt rock under high temperature shear strength parameter values as long as knovm salt rock strength parameters. 

Thermal Maturation. Organic microfossils such as spores and pollen can be used to indicate the temperature reached by the rocks (thermal maturity) that contain them because temperature increases as the rock is buried deeper. Organic microfossils are progressively altered by the loss of hydrogen and oxygen, and the resultant changes to physical properties such as color, reflectivity, and fluorescence can then be measured. 

Fractures are not only caused by external stress—processes like dolomitiza-tion result in volume reduction and create fractures and pore space in the rock. Thermal effects can also create fracturing. 

In fractured or cracked rocks, thermal conductivity is additionally influenced by the properties of crack-filling materials, fracture porosity, geometry, and distribution. 

Doveton, J.H., 1986. Log Analysis of Subsurface Geology. John Wiley Sons, New York. Drury, M.J., Jessop, A.M., 1983. The estimation of rock thermal conductivity from mineral content— an assessment of techniques. Zbl. Geol. PaliionL Teil 1, 35-48. 1983 H 1/2. Duffaut, K., Landro, M., 2007. Vp/Vs ratio versus differential stress and rock consolidation a comparison between rock models and time-lapse AVO data. Geophysics 72 (5), C81-C94. Dunham, R.J., 1962. Classification of carbonate rocks according to depositional texture. In Ham, W.E. (Ed.), Classification of Carbonate Rocks—A Symposium. AAPG Memoirs, 1, American Association of Petroleum Geologists, Tulsa OK/USA, pp. 108-121. 

Popov, Y.A., Pribnow, D.F.C., Sass, J.H., Williams, C.F., Burhardt, H., 1999. Characterization of rock thermal conductivity by high resolution optical scanning. Geothermics 28, 253-276. 

Thermal Properties and Temperature related Behavior of Rock/fluid Systems... 

Insulation. Impure sdiceous limestone and blast-furnace slag are the main raw materials for making rock-wool insulation bats and peUets (see Insulation, thermal). 

Thermal stabihty of the foaming agent in the presence of high temperature steam is essential. Alkylaromatic sulfonates possess superior chemical stabihty at elevated temperatures (205,206). However, alpha-olefin sulfonates have sufficient chemical stabihty to justify their use at steam temperatures characteristic of most U.S. steamflood operations. Decomposition is a desulfonation process which is first order in both surfactant and acid concentrations (206). Because acid is generated in the decomposition, the process is autocatalytic. However, reservoir rock has a substantial buffering effect. 

Synthetic fuels derived from shale or coal will have to supplement domestic suppHes from petroleum someday, and aircraft gas turbine fuels producible from these sources have been assessed. Shale-derived fuels can meet current specifications if steps are taken to reduce the nitrogen levels. However, extracting kerogen from shale rock and denitrogenating the jet fuel are energy-intensive steps compared with petroleum refining it has been estimated that shale jet fuel could be produced at about 70% thermal efficiency compared with 95% efficiency for petroleum (25). Such a difference represents much higher cost for a shale product. 

Anhydrite also has several common classifications. Anhydrite I designates the natural rock form. Anhydrite 11 identifies a relatively insoluble form of CaSO prepared by high temperature thermal decomposition of the dihydrate. It has an orthorhombic lattice. Anhydrite 111, a relatively soluble form made by lower temperature decomposition of dihydrate, is quite unstable converting to hemihydrate easily upon exposure to water or free moisture, and has the same crystal lattice as the hemihydrate phase. Soluble anhydrite is readily made from gypsum by dehydration at temperatures of 140—200°C. Insoluble anhydrite can be made by beating the dihydrate, hemihydrate, or soluble anhydrite for about 1 h at 900°C. Conversion can also be achieved at lower temperatures however, longer times are necessary. 

Hydrides of the types AnHi (An = Th, Np, Pu, Am, Cm) and AnHs (Pa —> Am), as well as ThaHis (i.e. ThHs.yj) have been so obtained but are not very stable thermally and are decidedly unstable with respect to air and moisture. Borides, carbides, silicides and nitrides (q.v.) are mostly less sensitive chemically and, being refractory materials, those of Th, U and Pu in particular have been studied extensively as possible nuclear fuels.Their stoichiometries are very varied but the more important ones are the semi-metallic monocarbides, AnC, and mononitrides, AnN, all of which have the rock-salt structure they are predominantly ionic... 

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