Abstract: A subsurface oil or gas reservoir is hydraulically fractured by injecting a fracturing fluid through perforations in the casing of a well penetrating into such subsurface reservoir. The fracturing fluid contains a clay stabilizing agent for stabilizing clay particles or fines along the face of the resulting formation fracture. A proppant comprising a gravel packing sand is injected into the fracture. Oil or gas is then produced from the reservoir through the fracture into the well.

Abstract: The potassium chloride concentration of a drilling fluid is monitored during well drilling operations to identify any depletion in such concentration with time. Initially, the gamma radiation measuring apparatus utilized is calibrated by making gamma radiation measurements on self-shielded drilling fluid samples having successively increasing potassium chloride concentrations. A calibration constant is derived from the measured relationship between the potassium chloride concentrations of the various drilling fluid samples and their respective gamma radiation count rates. This calibration constant is then used along with the measured gamma radiation count rates from drilling fluid taken during well drilling operations to identify drilling fluid potassium chloride concentration.

Abstract: A method and system for regulating current flow through a core sample from a subterranean formation being tested for electrical impedance, including a variable-frequency current source, means for passing such current through the core sample, means for measuring such current flow, and means for regulating the current flow through the core sample so that it is dependent upon the amplitude of the current flow from the current source and is independent of non-linear variations in core inpedance responsive to the current flow through the core sample.

Abstract: The operation of a dragline machine in digging below the earth's surface is monitored to provide measurements of the variations in pull cable length, lift cable length, and main boom inclination. From these measurements, the angle of inclination of the pull cable below the horizontal is determined. The depth of the excavation is then determined from the length of the pull cable and its inclination.

Abstract: A borehole logging tool employs an energy transmitter and receiver for scanning a borehole with energy pulses. An orientation pulse is produced each time the tool rotates past a predetermined orientation position. The time period between orientation pulses is measured and divided into a plurality of discrete intervals. Sine and cosine functions are generated for the measured time period having a sine and cosine value corresponding to each of the discrete intervals. The sine and cosine functions are used to produce sweep functions for controlling the outward sweep of the electron beam of a PPI display device so as to produce a circular rotating pattern in which each revolution corresponds in time to a measured time between orientation pulses. The output of the receiver modulates the electron beam sweep to generate a visual display of the azimuthal scan of the borehole.

Abstract: A seismic data gathering system includes a seismic cable having a plurality of cable sections, each including a seismic detector and a pair of signal lines for carrying the seismic energy signals produced by the detector in response to seismic energy waves. A shunting resistance is located in each cable section with one end connected to one of the pair of signal lines and the other end connected through a mating connector to the other of the pair of signal lines in the next succeeding cable section so that a shunting resistance is added to the seismic cable each time a detector is added to the seismic cable. In this manner the electrical damping of each seismic detector remains constant when the seismic cable is coupled to a data acquisition unit regardless of the number of detectors included within the seismic cable.

Abstract: A sample of an earth formation is subjected to a magnetizing field. The magnetic and non-magnetic fractions of the earth formation sample are separated while under the influence of the magnetizing field. The weights of the magnetic and non-magnetic fractions are measured and the weight percentage of the magnetic fractions determined. The presence or absence of select minerals in the non-magnetic fraction is determined on the basis of the weight percentage of the magnetic fraction.

Abstract: A borehole logging system includes a borehole gravity meter and a resistivity logging tool. A borehole gravity log and a resistivity log are produced over a select depth interval in a borehole. The bulk density of the subsurface formation surrounding the borehole over the select depth interval is measured from the gravity log. The bulk resistivity of the formation surrounding the borehole over the select depth interval is measured from the resistivity log. The bulk density and bulk resistivity measurements are combined to derive a measurement of the residual oil saturation of the subsurface formation surrounding the borehole for the select depth interval.

Abstract: A method for controlling the vertical growth of hydraulic fractures in subterranean formations. The fracturing gradients of adjacent formations are determined. The fluid density necessary to inhibit the propagation of a hydraulic fracture from one adjacent formation into the other is determined from the fracturing gradients. A fracturing fluid is prepared having the necessary density for inhibiting such hydraulic fracture propagation.

Abstract: A borehole logging system employs a compressional wave transmitter and a shear wave transmitter. The transmitters are alternately fired to impart compressional and shear waves into the formations surrounding the borehole. A bender-type receiver, spaced apart from the transmitter in the borehole is alternately gated so that the voltages across its pair of piezoelectric planar surfaces are subtracted during the expected time period of symmetrical motion of the receiver to provide a compressional wave output and added during the expected arrival time period of unsymmetrical motion of the receiver to provide a shear wave output.

Abstract: An acoustic positioning system for locating a marine cable at an exploration site employs a plurality of acoustic transponders, each having a characteristic frequency, at spaced-apart positions along the cable. A marine vessel measures the depth to the transponders as the vessel passes over the cable and measures the slant range from the vessel to each of the acoustic transponders as the vessel travels in a parallel and horizontally offset path to the cable.

Abstract: A logging sonde has directivity control of multiple sources and receivers in linear arrays. Each of the sources produces acoustic pulses which are delayed by a time delay between the sources to direct acoustic energy at an angle such that the resulting acoustic wave strikes a vertical formation orthogonally. The reflections of the acoustic pulses are detected with a linear array of receivers. The acoustic pulse detected by each receiver is delayed by an amount such that the total differential moveout for a reflected directional wave is zero.

Abstract: A magnetic susceptibility log is run through an earth formation to identify the presence of any select non-magnetic minerals in association with magnetic minerals. The select non-magnetic mineral is identified as being present when the magnetic susceptibility measurement exceeds a level at which a measurable concentration of the select non-magnetic mineral is expected to be present.

Abstract: A method of identifying potential low water cut hydrocarbon producing zones in sandstone formations lacking significant cementation and having relatively high log-indicated water saturations, implying the presence of significant amounts of unbound water. A formation is logged in a conventional fashion to determine porosity and fractional water saturation along the formation. A linear relation between porosity and water saturation is then derived, preferably by linear regression on pairs of log-indicated porosity and fractional water saturation values, each pair being taken from a different depth along the formation. Irreducible water saturation at any point along the depth of the formation is estimatable from the derived linear function and the log-indicated porosity of a formation at that depth.

Abstract: In seismic exploration, seismic reflection signals are obtained along a line of exploration. These seismic reflection signals are time shifted to correct for moveout caused by horizontal dipping and diffraction subsurface events. These connected signals are stacked with a dip independent velocity parameter to provide a zero source-to-receiver seismic record section enhanced in signal-to-noise ratio.

Abstract: An improved method of drilling a deviated well is effected by injecting a slug or series of slugs of a shear thickening fluid down the drill string ahead of the drilling fluid and into the annulus formed about the drill string to displace cuttings that accumulate in the annular regions where the drill string lies near the lower side of the deviated portion of the borehole thereby increasing cuttings transport efficiency. The shear thickening fluid has characteristics that enable it to dislodge and disperse the accumulated cuttings in that it undergoes a reversible, isothermal, increase in viscosity when subjected to an increasing shear rate. Slug volumes vary between 0.05 and 5 percent of the annulus volume between the drill string and the wellbore wall.

Abstract: A system for treating oil-contaminated drill cuttings includes a grinder for increasing the surface area of the drill cuttings to enhance the absorption of free oil on the cuttings. A mixer enhances the absorption of free oil into the additional solid, oil-absorbent material exposed through the increased surface area of the ground cuttings. After mixing, the ground cuttings may be compacted into individual masses of sufficient density to sink in water. Fine materials are separated from said compacted masses prior to disposal in a marine environment.

Abstract: A marine riser system is connected through flowlines and a moonpool plug assembly to a marine vessel. The moonpool plug assembly, when removed from the marine vessel, maintains a fully submerged position due to its having a buoyancy which is less than the net weight of the flowlines to which it is connected.

Abstract: In a rotary method of drilling a well into the earth employing a drilling mud system, the transport ratio (hole cleaning efficiency) is increased by increasing the yield point to plastic viscosity ratio of the drilling fluid while maintaining the plastic viscosity constant. In a preferred embodiment, the plastic viscosity is varied within the range of 7.5 to 30 centipoises and the yield point to plastic viscosity ratio is varied within the range of 0.20 to 1.5.

Abstract: In seismic exploration a seismic source transmits seismic energy into the earth and seismic detectors record the seismic waves returning to the earth's surface from reflecting subsurface interfaces. The downgoing transmitted seismic energy and the upcoming reflected seismic waves are transformed into the frequency domain, downward continued, and summed to produce a migrated seismic depth section.