Mechanical behavior investigation of Longmaxi shale under high temperature and high confining pressure

Abstract

Triaxial compression tests are conducted on Longmaxi shale under high temperature and high confining pressure condition corresponding to a depth of 3000 m for two typical bedding plane orientations (0° and 90°). It is found that the crack initiation stresses and crack damage stresses of the Longmaxi shale specimens with different vein orientations are different, reflecting that the inclination of the bedding plane has a non-negligible influence on the microcrack initiation and propagation. In addition, the brittleness index of the Longmaxi shale with a bedding plane orientation of 90° is greater than that with an orientation of 0°, which confirmed that the brittleness index is related to the structural orientation under a high temperature and high confining pressure condition. Concerning the failure patterns, both the shear and tensile fracture modes has been observed.

Measurement of shale gas in place based on different approaches and their comparison study

“…For shale gas reservoirs, the current volumetric methodologies are constructed on the basis of two volumes namely free and adsorbed gas volume. However, three forms of gas are present [5][6][7] in such reservoir e.g. (a) free gas which is stored in organic pore space and in natural fractures [8,9] and this can be determined by amendments of standard reservoir evaluation approaches, (b) adsorbed gas which is stored in organic matter i.e.…”