Abstract: Earth formation evaluation for detection of hydrocarbon fluids is carried out by a microwave frequency range sensor (antenna or wave guide) disposed in the face of a diamond or PDC drill bit configured to minimize invasion of drilling fluid into the formation ahead of the bit. The sensor is connected to an instrument disposed in a sub interposed in the drill stem for generating and measuring the alteration of microwave energy. In particular, the dielectric constant of the earth formation in a zone which is substantially uninvaded by drilling fluid may be detected and compared with density and/or porosity logs to determine the presence of hydrocarbons in relatively thin layers of formation material.

Abstract: There is provided a transient electromagnetic method and apparatus for inspecting objects. The apparatus includes a sensing portion, which has a transmitting antenna and at least one receiving antenna thereon. The sensing portion is located adjacent to the object which is to be inspected such that the antennas are adjacent to the object. There is also a magnet located adjacent to the sensing portion. The magnet has poles located adjacent to the object, so as to provide a steady-state magnetic field to the object. By applying a steady-state magnetic field to the object during inspection, increased inspection speeds and improved spatial resolutions can be achieved. In addition, casing can be inspected from inside of tubing.

Abstract: A method and apparatus for detecting and measuring gelled material (i.e. gelled pig) as it passes through a tubular by generating ultrasonic pulses at timed intervals which, in turn, are transmitted through said tubular and materials flowing therethrough at a fixed point along said tubular. These pulses are received after they have passed through said tubular and the materials and are processed to identify those pulses which travel through said gelled material as said gelled material passes by said fixed point. From the number of identified pulses, the length of the gelled pig can be determined.

Abstract: Earth formation evaluation for detection of hydrocarbon fluids is carried out by a microwave frequency range sensor (antenna or wave guide) disposed in the face of a diamond or PDC drill bit configured to minimize invasion of drilling fluid into the formation ahead of the bit. The sensor is connected to an instrument disposed in a sub interposed in the drill stem for generating and measuring the alteration of microwave energy. In particular, the dielectric constant of the earth formation in a zone which is substantially uninvaded by drilling fluid may be detected and compared with density and/or porosity logs to determine the presence of hydrocarbons in relatively thin layers of formation material.

Abstract: A tool which is capable of measuring parameters of a multi-phase flowstream without substantially restricting the flow in the wellbore is disclosed. The tool is comprised of a plurality of extendable arms which are radially spaced around and pivotably mounted in a housing so that each arm is extendable from the housing into the flowstream in the wellbore. Various types of sensors, e.g. flow sensors, capacitance sensors, temperature sensors, etc., can be used either alone or in combination which are carried at or near the outer ends of each of the arms whereby the sensors will be deployed from the housing into the flowstream by the arms without substantially restricting the flowstream through the wellbore.

Abstract: Perforations into an earth formation from a wellbore may be analyzed as to location, shape and radial depth by placing an inspection apparatus in the wellbore including an acoustic signal transmitter for transmitting acoustic signals over a broad bandwidth for a limited time, and receiving reflected or resonant acoustic signals excited in nearby perforations. The amplitude of the resonant frequency will reach a maximum when the perforation is at a midpoint between the transmitter and receiver. The resonant frequencies may be plotted as a function of signal power or intensity to determine perforation radial depth, based on the assumption that the perforation approximates an elongated cylindrical tube. Resonant frequency breadths may be compared to determine relative permeability of the formation and resonant frequency values may be compared to determine the shape of the perforation cavity.

Abstract: A transducer for an acoustic logging tool includes a liquid-filled cavity formed by a substantially rigid housing portion of the tool and having a resilient barrier member disposed between liquid in the wellbore and the liquid in the cavity. A magnetic field extends transversely through the cavity and a member, which may comprise a rigid plate, a flexible member or a quantity of electrically conductive liquid trapped between flexible membranes, is disposed in the cavity for movement normal to the magnetic field. A voltage is generated in response to movement of liquid in the cavity which is proportional to the velocity of the plate or member, or the velocity of the conductive liquid, the length of the conductive path and the intensity of the magnetic field in accordance with the principles of the Lorentz force.

Abstract: An acoustic signal transmitter for well logging tools and the like comprising a housing having a generally rectangular opening formed therein and defining a fluid filled cavity in which a compliant sheet transmitter member is disposed and is provided in a relaxed condition with a curvature. Opposite ends of the transmitter member are connected to piezoelectric actuators which are responsive to an electrical signal to elongate to stretch the sheet into a generally planar state to generate a pressure pulse in the cavity for transmission through a fluid filled borehole to a formation for, preferably, measuring the shear wave velocity in the formation material.

Abstract: A displacement amplifier interconnects a piezoelectric actuator with a displacement member and comprises respective bellows members of differential diameter defining first and second expansible chambers which are liquid filled and respond to linear displacement of a stack of piezoelectric disks to provide an amplified linear displacement to the displacement member. The transducer is particularly useful as a signal transmitting or receiving transducer for acoustic wave generation or measurement for wellbore logging tools.

Abstract: An acoustic wellbore logging tool transducer formed of a composite plate member having at least one plate of a magnetostrictive material which responds to a magnetic field to elongate or contract to effect displacement of said plate member within a cavity formed in a housing section of the logging tool. The logging tool cavity may be exposed to wellbore fluid in direct contact with the plate member whereby acoustic pressure pulses may be delivered directly to the wellbore fluid by the transducer element. Spaced apart electromagnets are disposed in the housing section on opposite sides of the cavity for effecting controlled displacement of the plate member to generate acoustic waves in a liquid-filled wellbore.

Abstract: A piezoelectric transducer includes a stack of plates of piezoelectric material which are energized to elongate in a predetermined direction and to provide amplified mechanical displacement to a drive member through a set of levers. The levers are connected at one end to a frame supporting the transducer, are provided with hinges between the point of connection and a point of engagement with the piezoelectric actuator and are also connected at their opposite ends to the drive member. The lever arms provide amplified linear displacement to the drive member in response to energization of the actuator. The lever arrangement also provides for exertion of high compressive forces on the piezoelectric actuator in response to a low force, large displacement-causing signal.

Abstract: Electrical signal-receiving transducers for logging tools include a silicon plate having piezoresistors formed thereon and response to deflection caused by pressure waves acting on said plate to generate an electrical signal through a bridge circuit including balancing resistors. Another embodiment of the transducer comprises a curved plate which is supported in a tool cavity for response to a pressure wave to deflect and exert forces on a piezoelectric element to generate a signal proportional to the deflection and a pressure wave causing such deflection. Monopole and quadrupole arrangements of the curved plate may be used for sensing or generating symmetric and asymmetric wave forms.

Abstract: A method for acoustically measuring wall thickness of tubular goods utilizes an acoustical transducer with a large bandwidth and high resonant frequency to measure the thickness of thin walls. The transducer is exposed directly to fluids in the tubular goods and is rotatable 360 degrees to scan the entire circumference of the tubular goods. The transducer is excited and generates an acoustic waveform from the wall under investigation. The acoustic return has a reverberation portion which results from the reverberation of the generated acoustic waveform in the wall. The harmonic frequency content of the reverberation portion is determined and the frequency difference between two adjacent harmonics is determined, from which the wall thickness is determined.

Abstract: A method and tool for acoustically logging a wellbore where a transmitter simultaneously generates a plurality of separate acoustical signals having different frequencies, each effectively centered about a different resonance frequency, and then transmits the signals as a composite multi-frequency output signal having an effective broad frequency bandwidth that is capable of exciting pressure waves in a variety of different types of earthen formations.