Abstract: The present invention provides a cell for the triaxial stress testing of a rock sample, comprising a central body in which is placed a membrane enclosing said sample and exerting lateral stresses thereon, as well as a vertical pressure means acting on a section of the sample, said cell further comprising means for measuring the deformations of the sample related to the stresses which are applied thereto. The membrane has a central lateral opening in which the sample is introduced, a lateral external surface coming into contact with the body of the cell and a hollow internal volume forming a chamber providing confinement by means of a fluid introduced through an orifice.

Abstract: Device for carrying out tests on materials such as rock samples for example, on which triaxial stresses are exerted.The device comprises an extended body with a central cavity where a first part (6) of a sonic sonde, a sole piece (9) carrying a cubic sample (12) for example, jacks (13) which are introduced along the lateral faces of the sample by connecting them with channels (25) supplying fluid under pressure are successively placed. A centering piece (27) containing a box (26) for another part (28) of the sonic sonde and elements (31, 32) forming a cover are placed above. A piston (35) allows to apply stresses to the sample by means of the box (26). Lateral sensors (22) pick up the displacements of the sample.Application to the examination of rocks taken from a subterranean formation for example.

Abstract: A technique for liquid treating a geological formation comprises spraying the liquid with a pressurized carrier gas, using a spraying pipe whose length and diameter are adjusted as a function of the pressure prevailing at the level of the formation and of the characteristics of the injected liquid and the pressurized carrier gas, so that the size of the liquid droplets at the outlet of the spraying pipe has a narrow range of distribution about a single preselected value.

Abstract: A technique for liquid treating a geological formation comprises spraying the liquid with a pressurized carrier gas, using a spraying pipe whose length and diameter are adjusted as a function of the pressure prevailing at the level of the formation and of the characteristics of the injected liquid and the pressurized carrier gas, so that the size of the liquid droplets at the outlet of the spraying pipe has a narrow range of distribution about a single preselected value.

Abstract: A propping agent for fractures produced in the walls of a bored well comprising a granular or particulate product containing on the basis of its oxide content up to 85% by weight zirconium oxide (ZrO.sub.2) in a quantity which is such that the weight ratio of ZrO.sub.2 /SiO.sub.2 is equal to or greater than 1.5, alumina (Al.sub.2 O.sub.3) in a quantity which is such that the weight ratio Al.sub.2 O.sub.3 /SiO.sub.2 is between 0 and 1.5 and sodium oxide (Na.sub.2 O) in a quantity which is such that the weight ratio Na.sub.2 O/SiO.sub.2 is between 0 and 0.04.

Abstract: Process for determining characteristics of the geological formations traversed by a borehole, making use of a sonde by means of which the intensity of the .gamma. rays naturally radiated from the formations is measured, both longitudinal and transversal acoustic waves are transmitted to the formations, their travel time and their attenuation between two receivers placed in contact with the formations are measured and by combination of the so-obtained values a resulting value is elaborated which is representative of one characteristic of the surveyed formations.

Abstract: Process for determining characteristics of the geological formations traversed by a borehole, making use of a sonde by means of which the intensity of the .gamma. rays naturally radiated from the formations is measured, both longitudinal and transversal acoustic waves are transmitted to the formations, their travel time and their attenuation between two receivers placed in contact with the formations are measured and by combination of the so-obtained values a resulting value is elaborated which is representative of one characteristic of the surveyed formations.