Abstract: An apparatus for the in situ measurement of the deformation and stress conditions of a string of casings in a drilled oil well is provided with an antimagnetic measuring section mountable in the string of casings at a selected depth and having extensometers fixed on the mantle thereof and a first electronic unit. The unit includes printed circuitry mounted on the measuring section and receptive of the signals from the extensometers for transmitting same. The apparatus also includes a drill hole probe extendable into the interior of the casings to the depth of the measuring section and a second electronic circuit receptive of the transmission from the first electronic circuit to apply same to a cable attached thereto for processing at the surface.

Abstract: Process and apparatus for the ultrasonic treatment of underground rocky strata, primarily for drilling therein, and for increasing the permeability of the strata. A flushing medium is made to flow through a mechanical drilling tool such as a rotary drill bit with rock-breaking elements, a pressure wave is superposed on the static pressure of the flowing medium at the location of rock breaking, and the frequency of the pressure wave in the ultrasonic range, preferably between 20 and 100 kHz; good results have been obtained at 27 kHz. The inventive apparatus includes a passageway in the tool for the flushing medium, a resonance chamber in the path of the medium, together with an exciting or interference element, constituting means for changing the flow conditions of at least part of the medium from laminar to turbulent, producing therein a pressure wave, and superposing the latter, as aforesaid. The resonance chamber preferably opens into a jet nozzle forming part of the drilling tool.

Abstract: The invention concerns apparatus for performing underground measurements during drilling of underground strata using conventional measuring instruments. It comprises a closed instrument casing filled with oil, an adaptor coupling the casing to the drilling pipe, a spring holder connected to the instrument casing and carrying damping spring means, a helical plate controlling angular displacement and a piston-and-cylinder displacement control device, a first bore in the adaptor for conveying mud to a downward section of the drilling pipe, a second closable bore in the adaptor for permitting mud to flow from the annular space around the pipe through the instrument casing, and a closable bore in the instrument casing for communicating the pressure in the interior of the drilling pipe to the instrument casing.