Abstract: A borehole logging tool having a dipole acoustic energy source and at least one spaced-apart dipole acoustic energy receiver is lowered into a deviated borehole. A motor rotates the source and receiver about the axis of the borehole tool. A first signal is produced representing source and receiver rotational position relative to rotational position of the borehole tool. A second signal is produced representing rotational position of the borehole tool relative to a vertical direction. A comparator produces a third signal of the difference between the first and second signals as a representation of source and receiver rotational position relative to the vertical direction. The motor rotates so as to minimize such third signal, thereby rotating the focus of the source and receiver in a direction perpendicular to the eccentricity of the borehole tool in the deviated borehole.

Abstract: A method and apparatus for gravel packing an interval of a wellbore wherein a permeable screen having a means for restricting fluid flow from the annulus into the upper portions of the screen is positioned adjacent the wellbore interval. The flow-restrictive means may be comprised of any material which remains substantially solid during circulation of the gravel slurry but preferably is a material that can be removed, e.g. by melting or dissolving, after the gravel has been placed. Examples of such material are (1) blends of waxes; (2) eutectic compounds formed by combining organic compounds; (3) salts; and (4) asphaltenes which are soluble in crude oil. The flow-restrictive means also may be formed of a perforated metal sleeve which is dissolvable by acid.

Abstract: A two-phase fluid, flow having a first fluid and an immiscible second fluid, is passed through a core sample. The core sample is scanned with X-rays to produce a display of fluid distribution within the core sample. Electrical resistivity is measured along the length of the core sample for those intervals having uniform first fluid distribution. The two-phase flow is continued to repetitively decrease the first fluid saturation in a plurality of drainage cycles with electrical resistivity being again measured for each drainage cycle. Thereafter, the two-phase fluid flow is continued to repetitively increase the first fluid saturation in a plurality of imbibition cycles with electrical resistivity being again measured for each imbibition cycle.

Abstract: X-ray attenuation measurements at two or more energies are carried out on core samples of earth materials for use in determining the relative contributions of Compton scattering and photoelectric absorption to the attenuation of the beams of X-rays by the samples. The measurements are utilized to calculate material bulk density, responsive to the difference in attenuation measured with respect to beams of two different X-ray energies and the attenuation of the beams of one of X-rays.

Abstract: A method for producing multiple fractures by a single operation from a single wellbore which penetrates a fracture interval which, in turn, includes a plurality of zones which break-down under different fracturing pressures. Fracturing fluid is delivered from a workstring directly to different levels within a section of the wellbore which lies adjacent the fracture interval through a plurality of alternate paths which, in turn, lie substantially adjacent to the zones to be fractured.

Abstract: A method and apparatus for treating multiple strata in a single operation from a single wellbore which penetrates a treatment interval which, in turn, includes a plurality of strata which, in turn, have different permeabilities. A treating fluid (e.g. consolidating agent, acid, etc.) is delivered directly to different levels within a section of the wellbore adjacent the interval to be treated through a plurality of alternate paths which, in turn, lie substantially adjacent to the strata to be treated.

Abstract: A borehole logging tool having a dipole acoustic energy source and at least one spaced-apart dipole acoustic energy receiver is lowered into a deviated borehole. A motor rotates the source and receiver about the axis of the borehole tool. A first signal is produced representing source and receiver rotational position relative to a vertical direction. A second signal is produced representing a fixed reference level. A comparator produces a third signal of the difference between the first and second signals. The motor rotates so as to minimize such third signal, thereby maintaining the focus of the source and receiver in a horizontal direction that is perpendicular to the direction of eccentricity of the borehole tool with respect to the borehole axis.

Abstract: A self-contained, programmable temperature sensor is positioned within a suitable pressure housing affixed to a borehole tool to record and store temperature data at predetermined times during operations of the borehole tool in a borehole penetrating a subsurface formation. The depth of the temperature sensor within the borehole corresponding to each temperature reading is recorded. After the borehole tool is removed from the borehole, the temperature sensor is removed from the pressure housing and the stored temperature data is retrieved for use in producing a record of borehole temperature versus depth within the borehole at the programmed times.

Abstract: An improved tool for controlling the rate of flow of cement into a well to control the consolidation of a formation is disclosed. The tool comprises a housing, an actuator and a valve member, motion of which is controlled by axial motion of the actuator within the housing. In the preferred embodiment, the valve member includes a fixed size choke orifice which controls the flow of cement into the formation. The tool is operated by lowering it into a well with the valve open, fixing the housing to the casing of the well, pumping cement below the valve, lowering the actuator with respect to the housing to close the valve, and pressurizing the well to force the cement into the formation at a rate controlled by the size of the choke orifice.

Abstract: Electrical contact is made between an electrode and a liquid column to establish current flow between the electrode and the liquid column. The electrode is raised up the liquid column until electrical contact is broken. An additional quantity of liquid is added to the liquid column to cause the column to rise and make electrical contact with the electrode. The electrode is raised up the liquid column until electrical contact is again broken. The distance of travel of the electrode is measured as a determination of the rise in height of the liquid column and of the additional volume of liquid added to the column.

Abstract: Apparatus for gravel packing a wellbore interval having shunt means (i.e. conduits) on the external surface of a sand screen which can selectively deliver a gravel slurry to different levels of the interval during operation. The shunt means is comprised of a variety of differently configured, perforated conduits and/or arrangements of these conduits.

Abstract: The maximum correlation between a pair of curves is determined from the maximum value of the common area of such curves with respect to reference lines within a select window as one of the curves is moved through the window while the other of the curves remains fixed within the window.

Abstract: A cylindrical core sample of a subterranean formation is place into a sleeve under confining pressure. At least one electrode array extends through the sleeve and makes contact with the core sample. The array is in a plane normal to the core sample and has an even number of electrodes equally spaced about the sleeve. A current is passed through the core sample and voltages are measured across each pair of electrodes that are spaced 180.degree. apart around the sleeve. Such measurements are utilized to identify the radial direction of any electrical anisotropy in the core sample, particularly under differing fluid saturation conditions.

Abstract: A method and apparatus for laboratory simulation of the dynamic formation of sand arches in production of oil and/or gas from unconsolidated or poorly consolidated wells is disclosed. An ultrasonic transducer is disposed opposite a perforation in a member simulating the casing of a well and the simulated well is operated at conditions approximating those of interest in the field. The acoustic transducer is moved incrementally across the perforation and measurements of the distance between the transducer and the formation are measured. These can then be used to generate a profile of the surface of the formation behind the perforation. Preferably, an ultrasonic transducer which emits a focussed beam of acoustic energy is employed.

Abstract: An improved centralizer for well casing, comprising an externally threaded upper anchor fixed to the casing, an upper collar threaded to the upper anchor, a lower anchor fixed to the casing, a lower collar bearing against said lower anchor, and a plurality of relatively flexible metallic straps extending between the collars. The centralizer is assembled over a section of well casing as the casing is lowered into the well. When the casing reaches its final depth, it is rotated so that the anchors rotate with the casing, while the collars and the straps remain stationary, as the straps engage the wellbore. When the casing is thus rotated, the upper collar moves along the threads of the upper anchor towards the lower collar, axial movement of which is prevented by the lower anchor. This forces the straps to bulge outwardly away from the casing, urging the casing toward the center of the borehole.

Abstract: A transversely isotropic cylindrical core sample of a subterranean formation is fluid saturated and subjected to a confining pressure. Electrical potential is measured along the core sample and in a plurality of direction through the core sample which are normal to the cylindrical axis of the core sample at a plurality of spaced-apart positions along such axis. From these electric potential measurement tensor conductivity components normal to and lying within the bedding plane of the core sample are determined.

Abstract: A cylindrical core sample of a subterranean formation is fluid saturated and subjected to a confining pressure. Voltages are measured in a plurality of directions through the core sample which are normal to the cylindrical axis of the core sample at a plurality of spaced-apart positions along such axis and utilized to determine resistivities. These resistivities are compared to identify the radial direction of any electrical anisotropy in the core sample for differing fluid saturation conditions.

Abstract: A sand screen is positioned in a well adjacent an oil or gas reservoir to be produced. At least one conduit is in juxtaposition with the sand screen and has passageways at selected intervals to establish fluid communication between the conduit and the annulus of the well surrounding the sand screen. A gravel packing slurry is injected down the well to form a gravel pack in the annulus. Actuatable devices associated with the conduit passageways control fluid flow between the conduit and annulus so that if the gravel portion of the slurry forms a bridge in the annulus, thereby blocking slurry flow through the annulus, the slurry will be diverted from the annulus into the conduit through one or more of the passageways in the conduit above the bridge, downward through the conduit and out through one or more passageways in the conduit into the annulus below the bridge to continue the forming of the gravel pack in the annulus.

Abstract: A water-saturated core sample of a porous rock is placed in a sleeve which a hydrophobic membrane in one end and a hydrophilic membrane in a second end. A pressurized hydrocarbon is injected into the core sample through the hydrophobic membrane to displace the water in the core sample whereby it drains through the hydrophilic membrane into a collector. Upon a depressurization of the injected hydrocarbon below the displacement pressure of the hydrophilic membrane, the water imbibes back into the core sample through the hydrophilic membrane. Upon a pressurization of the imbibing water above atmospheric pressure the water displaces the hydrocarbon from the core sample through the hydrophobic membrane.

Abstract: A core sample of a porous rock having a wettability representative of a subterranean formation is saturated with a first medium. This first medium is then displaced with an immiscible second medium. Capillary pressure versus wetting phase saturation is measured during the displacement of the first medium with the second medium within the core sample. Mercury is injected into an evacuated core sample of the porous rock, mercury vapor acting as a wetting phase on the porous rock. Capillary pressure versus wetting phase saturation is measured during mercury injection on the evacuated core sample. The ratio of the two capillary pressure versus wetting phase saturation measurements is determined and taken to be an indicator of the wettability of different size pore throats in the porous rock.