Abstract: Method and apparatus are provided for determining the formation pressure. The magnitude of formation pressure may be derived as a function of changes in bottomhole pressure following swabbing the borehole to draw formation fluids into the borehole, monitoring the borehole for influx of formation fluids, determining the reduced pressure due to swabbing, repeating the swabbing and monitoring steps until an influx of formation fluids is detected thereby determining the pressure of the formation.

Abstract: An apparatus and method for measuring fluid characteristics, particularly useful in performing measurements in remote and severe environments is disclosed. The probe employs an ultrasonic transmitter and receiver, preferably a unitary ultrasonic transducer to both transmit and receive the ultrasonic signal. Further, the probe includes an internal reference reflecting surface hermetically sealed from contact with the fluid and one or more solid/fluid reflecting surfaces as are required. Preferably, two solid/fluid reflecting surfaces are located on opposite sides of a fluid receiving gap. The apparatus and method are useful in measuring fluid characteristics both at remote surface and in downhole drilling locations.

Abstract: A well fluid and method for borehole sealing such as grouting or plugging, the fluid being comprised of water, a water swellable clay and a water dispersible polymer which prevents immediate hydration of the clay.

Abstract: Hydroxyethyl cellulose and a sequestrant are added to a heavy brine containing one or more salts selected from calcium chloride, calcium bromide, and zinc bromide to increase the viscosity of the brine. Preferably the brine contains zinc bromide, has a density in the range from about 14.2-19.2 pounds per gallon, and the sequestrant is a polyphosphonic acid or water soluble salt thereof.

Abstract: The present invention is directed to a method for optimizing the tripping velocity of a drill string. The method of the present invention comprises determining the hydraulic fluid pressure in the borehole in a plurality of intervals as the drill string is pulled out of or run into the borehole. These actual pressures are compared against a predetermined acceptable pressure range for each interval. The limits for this acceptable pressure range are set by the maximum acceptable surge pressures and the minimum acceptable swab pressures established for the interval. The velocity of the drill string in each such interval is then adjusted in order to maximize the tripping velocity while maintaining the hydraulic fluid pressure within the acceptable range for each interval.

Abstract: A drill bit comprises a bit body having an operating end face. A plurality of self-sharpening cutters are mounted in the bit body and extend through the operating end face. The cutters have cutting faces adapted to engage an earth formation and cut the earth formation to a desired three-dimensional profile. The cutting faces define surfaces having back rake angles which decrease with distance from the profile. The individual cutting faces may be inwardly concave in a plane parallel to the intended direction of motion of the cutter in use.

Abstract: A rotary drilling drag bit for drilling from the surface deep holes in sub-surface formations e.g. for oil has a body (4) with a diameter of at least 100 mm and having a bore for passage of drilling fluid to its face (3) and rotatable cutting elements (6) having a cutting face comprising an agglomerate of diamond particles so mounted on the body (4) that they are free to rotate in use.The cutting elements are of long life and highly effective in drilling.

Abstract: A shear ram-type blowout preventer for severing and sealing a drill pipe string comprises a housing having a throughway for receipt of the drill pipe. Opposed first and second ram assemblies are mounted in the housing on opposite sides of the throughway for reciprocation laterally inwardly and outwardly. Each of the ram assemblies comprises a carrier connected to a drive member for effecting such reciprocation, and a ram block carried on the laterally inward side of the carrier. The maximum thickness of the block is generally equal to the maximum thickness of the carrier measured longitudinally of the throughway. The first ram assembly comprises a blade member carried on the ram block and including a cutting portion extending generally laterally inwardly and a mounting shank extending generally upwardly from the cutting portion. The shank is attached to the ram block by generally horizontally disposed pins.

Abstract: The invention comprises a drag-type drill bit and a cutting member therefor. Each of the cutting members comprises a stud having a shank adjacent one end mounted in a respective bore in the bit body and a head adjacent the opposite end projecting outwardly from the bit body. The head has a lip formation adjacent the juncture of the head and shank. The lip extends laterally outwardly with respect to the shank to overly the outer surface of the bit body adjacent the respective bore. The cutting face is concave, presenting a plurality of different back rake angles, which angles increase with distance from the lip formation.

Abstract: A high permeability ferrite core, which includes a gap between adjacent ends thereof, is combined with a magnetic coil encircling the core, and is located in a sub positioned in the drill string just above the drill bit of a borehole drilling rig. The core is positioned so that the gap thereof lies across a recess region formed in the outer wall of the sub. Drilling fluids flow along the outer surface of the sub on the return path from the drill bit to the mud pits located at the surface of the borehole. A constant current, or voltage, at a frequency within the range of 20 KHz-20 MHz is applied to the terminals of the coil encircling the core and the eddy currents developed in the gap region produce a measurable back emf at the coil terminals. The current produced by this emf voltage is indicative of the resistivity of the drilling fluid within the recess region in the wall of the sub and the fluctuations of the voltage accurately follow the variations in drilling fluid resistivity.

Abstract: Method and apparatus for measuring the flow velocity of drilling mud returning from the annulus of a borehole. At least two parametric acoustic pulse transducers are longitudinally disposed with respect to a conduit with a pair of acoustic receivers positioned therebetween. The transducers each generate strong, focused acoustic waves comprised of combined dual frequencies directed at the center of the conduit area in which fluid flow is to be measured. The transducers are actuated alternately and produce time variant signals permitting measurement of fluid flow by employing the Doppler effect on the parametric secondary acoustic pulses. The utilization of combined dual frequency acoustic transducers provides a primary signal having sufficient strength to produce a non-linear response in the liquid and produce secondary, low frequency wave propagation directly from within the mud itself. The low frequency waves enhance wave propagation through gas cut muds and enhance signal recognition in the receivers.

Abstract: A latch device for controlling a valve in a mud pulse telemetry system for imparting data pulses to drilling fluids circulating in a drill string is disclosed. A latch device and valve arrangement including an improved shear type, solenoid operated valve for modulating the pressure of the circulating drilling fluid is disclosed. A latching solenoid armature is connected to the valve gate through separate open and close solenoids having their armatures operatively connected to act as a single unit. The single unit armature is normally restrained from movement by the solenoid deactivated latch device. The latch device is arranged so that the vibrational and impact loads on the drill string serve to further maintain the modulating valve in a closed position.

Abstract: The present invention is directed to an apparatus and method for preventing diffusion of a gas under high pressure into the bulk of a liquid filling a substantially closed chamber. This apparatus and method is particularly useful in connection with test devices for testing fluid characteristics under harsh conditions of extremely high pressure and high temperature. These devices typically pressurize the liquid by placing the liquid in pressure and fluid communication with a high pressure inert gas. The apparatus and method of the present invention prevent diffusion of the pressurizing gas into the bulk of the test liquid by decreasing the chamber volume at a rate sufficient to maintain the bulk of the liquid free of absorbed or dissolved gas by expelling that portion of the liquid which is contaminated by the pressurizing gas.

Abstract: A high pressure seal assembly for use with an insert cover positioned in a downhole tubular housing, the assembly having a flange which is deformable by the pressure differential between higher pressure on the exterior of the insert cover and the lower pressure on the interior of the insert cover. A portion of the flange is deformed to mate against the tubular housing. In a preferred embodiment, the flange has two legs, one being attached to the insert cover and the second being the deformable portion having deformable spacer material positioned between the second leg of the flange and the housing.

Abstract: A drilling mud flow rate detector, including a sub adapted for being positioned in the drill string, having a sonic signal generator located near the center of the sub in both the incoming mud flow path and the return mud flow path. A set of sonic signal receivers is located at both ends of the sub in both the mud input flow path and the mud return flow path and corresponding sets of sonic signal transmitters are located near the center of the sub. The distance between the transmitting transducers at the center of the sub and the receiving transducers located at each end of the sub are equal so that under a condition of no mud flow, the sonic signals arrive at each end of the sub simultaneously. During mud flow, "doppler effect" will produce phase shifts in the sonic signals which are proportional to the direction and the rate of mud flow. Signals received by the receiving transducers are processed to produce an input mud flow rate signal and an output mud flow rate signal which are then compared.

Abstract: An oil base packer fluid for use in completing oil and gas wells comprising:(a) a liquid oleaginous medium;(b) an organophilic clay comprising the reaction product of an organic onium compound and a smectite clay;(c) a polar dispersant for said clay; and(d) a polyfunctional amino silane represented by the formula: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each selected from the group consisting of hydrogen, alkyl, aryl, cycloalkyl, and alkylaryl; and X is selected from the group consisting of alkylene, arylene, alkarylene, arylalkylene, cycloalkylene, aminoalkylene, aminoarylene, aminoalkylarylene, aminoarylalkylene and aminocycloalkylene.The packer fluids are characterized by being thin and pumpable at temperatures up to about 130.degree. F. but are gelled to form an insulating medium at temperatures above about 130.degree. F.

Abstract: In a drilling operation fatique producing vibrational motion is produced in the drill string in the form of longitudinal and torsional load variations at the drill bit and throughout the bottom hole assembly. These load variations occur at least partially as a result of the irregularly shaped hole bottom which develops beneath the bit and which in turn cause the bit to rise and fall with rotation, and the bit loading to vary. In addition, the rotating drill string causes gyrations in the drill string which are transmitted to the bottom end of the drill string and drill bit in the form of load and torque variations. These variations in loading appear as longitudinal and torsional vibrations in the drill string. A dampening and shock absorbing mechanism is at least partially comprised of piezoelectric elements which are responsive to the vibrations of the drill string to produce electrical energy which is used to operate downhole electrical circuits.

Abstract: An organophilic clay gellant useful for gelling organic liquids is disclosed which comprises the reaction product of (a) a smectite-type clay having a cation exchange capacity of at least 75 milliequivalents per 100 grams of said clay; (b) a primary anion selected from the group consisting of anions derived from organic sulfonic acids, alkylsulfates and mixtures thereof containing at least one lineal or branched alkyl group having greater than 9 carbon atoms, aromatic sulfonic acids and mixtures thereof; (c) a secondary anion different from said primary anion and selected from the group consisting of anions derived from organic acids having a pKa of less than about 11.

Abstract: A device for determining the stuck point of a drill pipe in a borehole consisting of two relatively movable sections, anchoring means for each section, a sensing means for detecting relative movement of the two sections and producing an inductance representative of the movement. The inductance is transformed into a frequency modulated signal which is transmitted to the surface and converted from a non-linear direct current voltage representation of relative movement to a linear direct current voltage.

Abstract: Process for the removal of hydrogen sulfide from gas mixtures, particular gas mixtures containing hydrocarbons, wherein the gas mixture is treated with an aqueous solution of a water soluble nitrite such as sodium nitrite, the pH of the aqueous solution being at least 5.5 or greater.