W. H. Somerton, A. H. Janah and P. I. Ashqar
University of California, Berkeley
ABSTRACT
Linear thermal expansions and pore volume thermal contractions have been measured for three liquid saturated outcrop sandstones subjected to confining stress and pore fluid pressure. Linear thermal expansions were found to be not much different from values for dry, unstressed samples. The presence of quartz appears to dominate the thermal expansion behavior in both cases.
Pore volumes of liquid saturated sandstones under stress decrease with increased temperature. Pore volume thermal contraction is a strong function of porosity, values decreasing with increased porosity, and is probably strongly affected by the quartz content of the particular sandstone. Pore volume thermal contraction is only slightly affected by the magnitude of the
confining stress, but is strongly affected by the pore fluid pressure.
Changes in pore volume due to reservoir heating are probably not very large. Increasing the temperature from 100 deg C to 200 C would reduce the porosity by about one percent. At lower pore pressures and higher temperatures, the porosity change would, of course, be greater.