Abstract: Transmission and reception of sonic waves and the adjustment of the water level in columns are utilized to establish a desired differential pressure across a core sample. The technique utilized to establish a desired differential pressure across a core sample can also be used to calibrate a differential pressure transducer if desired.

Abstract: Water is injected into a core sample which has been restored to a desired state of water and gas-oil saturation and which is subjected to desired conditions of pore pressure, overburden pressure and temperature. A measurement of the rate at which oil is forced from the core sample by the injected water provides an indication of the imbibition characteristics of the core sample and thus of the rock formation from which the core sample was taken. The technique utilized to establish a desired differential pressure across a core sample can also be used to calibrate a differential pressure transducer if desired.

Abstract: Provided is an apparatus for taking core samples from the side of a borehole which comprises a gun body having a transverse shooting bore, a projectile adapted to be shot from the bore, a tether for tethering the projectile to the gun body, and a permanent magnet for holding the projectile to the gun body at the end of the tether.

Abstract: Provided is an apparatus for taking core samples from the side of a borehole which comprises a gun body having a transverse shooting bore, a projectile adapted to be shot from the bore, a tether for tethering the projectile to the gun body, and a permanent magnet for holding the projectile to the gun body at the end of the tether.

Abstract: A time measuring system is provided which automatically compensates for the propagation time of electrical pulses and sonic waves through the apparatus associated with a core analysis system. In this manner, the time required for a sonic pulse to propagate through a core sample is measured exactly and the velocity of the sonic wave through the core sample is calculated based on the propagation time and the sample length.

Abstract: The permeability of a rock formation is determined at elevated pressures and temperature by heating a core sample taken from the rock formation and a fluid which is utilized to determine the permeability of the core sample to an elevated temperature. The fluid is injected under pressure and a second pressure which is higher than the injection pressure is applied to the surface area of the core sample. The effect of injecting a fluid such as a corrosion inhibitor or a polymer useful in secondary or tertiary recovery techniques on the permeability of the rock formation can be determined at elevated pressures and temperature by comparing the permeability of the rock formation before the fluid is injected and after the fluid is injected.

Abstract: Acoustical logging apparatus is utilized to determine the need for consolidation treatment of an oil-bearing sand formation prior to production and preferably prior to the removal of the drill rig. The relative energy levels and/or the relative velocities of the compressional and shear waves are measured and the ratio of the compressional energy to shear energy and/or the ratio of compressional velocity to shear velocity is utilized to provide an indication of the need for sand consolidation treatment.

Abstract: An electrical well logging system is disclosed wherein the well logging tool is enclosed at least in part by an expandable sleeve having a band of electrodes located in the outer surface thereof. The band of electrodes is located in a plane which is perpendicular to the vertical axis of the well logging tool. When the well logging tool is in a desired position in the borehole, the expandable sleeve is expanded to place the electrodes located therein in contact with the adjacent sidewall surface of the borehole. Current is injected into the formation surrounding the borehole and the voltage induced by the current is measured. A phase comparison of the current injected into the formation and the voltage sensed in response to the injected current can be utilized to determine if clay is present in the formation.

Abstract: A new location arrangement is made of a shear transducer in a transducer sonic velocity apparatus, as for core testing, in which a shear transducer is placed between or next to a contact piece and a compression transducer so that loading of the shear generator by the compression transducer is avoided. In another embodiment, both the shear and compressional transducers are at substantially the same point or in the same plane so that the time zero is the same for both the compressional and shear measurements. In another embodiment, the shear transducer surrounds, but does not contact, the compressional transducer, and both the shear and compressional transducers contact a mounting plate or platen in about the same plane so that the time zero is the same for both the compressional and shear measurements.Increased shear and compressional signals can be obtained by placing an oil depending film between a shear and its corresponding compressional transducer.