Pulse echo apparatus and methods are disclosed for measuring characteristics of a borehole while it is being drilled. A component of a bottomhole assembly, preferably a drilling collar, is provided with one or more ultra-sonic transceivers. A pulse echo sensor of the transceiver is preferably placed in a stabilizer fin of the collar, but may also be placed in the wall of the collar, preferably close to a stabilizing fin. Electronic processing and control circuitry for the pulse-echo sensor is provided in an electronic module placed within such collar. Such pulse echo apparatus, which preferably includes two diametrically opposed transceivers, generates signals from which standoff from a borehole wall may be determined. A method and apparatus are provided for measuring standoff and borehole diameter in the presence of drilling cuttings entrained in the drilling fluid. In a preferred embodiment, such signals are assessed by the electronic processing and control circuity to determine if gas has entered borehole. Three methods and apparatus are provided for such gas entry determination. The first relies on measurement of sonic impedance of the drilling fluid by assessing the amplitude of an echo from an interface between the drilling fluid and a delay-line placed outwardly of a ceramic sensor. The second relies on measurement of drilling fluid attenuation of a borehole wall echo. The third relies on measurement of the phase of oscillations of echoes to identify large gas bubbles entries. The pulse-echo sensor includes a sensor stack including a backing element, a piezo-electric ceramic disk, and a delay-line.

Ultrasonic measurement apparatus

A device (30) for sensing fluid behavior, e.g. flow, in a conduit (34) such as downhole in a well, comprises a tool (36) having two or more spaced sensors (38,40) for interacting with a medium within the conduit to produce data signals. The sensor data signals may be compared to determine movement of the medium within the conduit and about the device. The device is particularly suited for determining movement of multi-phase fluid.

Device for sensing fluid behavior

An apparatus and a method are provided for measuring the caliper of a borehole, and the standoff of a drilling tool from the walls of a borehole during a drilling operation. The apparatus includes three or more sensors, such as acoustic transducers arranged circumferentially around a downhole tool or drill collar. The transducers transmit ultrasonic signals to the borehole wall through the drilling fluid surrounding the drillstring and receive reflected signals back from the wall. Travel times for these signals are used to calculate standoff data for each transducer. The standoff measurements may be used to calculate the caliper of the borehole, the eccentricity of the tool in the borehole, and the angle of eccentricity with respect to the transducer position. The eccentricity and angle computations may be used to detect unusual movements of the drillstring in the borehole, such as sticking, banging, and whirling.

Apparatus and method for measuring a borehole

An optical fiber cable connector assembly includes a first tubular housing (1) and a second tubular housing (2) connected to each other by complementary threads (12) and (211). An alignment ferrule (3) positioned within the inner hollow portions of the first housing (1) and the second housing (2) is provided for enclosing and fastening an optical fiber cable (9) therein, and is associated with a coil spring (4) to provide a resilient bumper effect. The rear portion of the alignment ferrule (3) is dimensioned to extend out of the rear end of the second housing (2) a predetermined distance. A coupling nut (5) is slidable axially around the first housing (1) and the second housing (2) for coupling to a corresponding connector. An extension ferrule (6) abutting against the rear end of the second housing (2), is surrounded by the cable jacket (94) and the strength members (93) separated from the optical fiber cable (9) wherein the strength members (93 ) further extend over the rear portion of the second housing (2), and a crimping ferrule (7) presses the strength members (93) and the jacket (94) onto the rear portion of the second housing (2) and onto the extension ferrule (6). A boot (8) surrounds the crimping ferrule (7) and covers a portion of the optical fiber cable close to the crimping ferrule (7).

Optical fiber connector assembly

A two-channel fiber optic rotary joint of this invention can transmit simultaneously optic signals along two optic passes through a single mechanical rotational interface. The first channel of light path consists of a pair of fibers, co-axially fixed in 2 holders respectively. The light signal from one of the fiber can be directly coupled into another fiber. The second channel of light path is off-axis arranged, including a pair of conventional collimators, a pair of first reflecting surfaces and a pair of second reflecting surfaces. The light signal emitted from one of the said conventional collimator will be reflected by one of the said first reflecting surface, one of the said second reflecting surface, another said second reflecting surface, and another said first reflecting surface, then coupled into another said conventional collimator.

Two-channel, dual-mode, fiber optic rotary joint

A measuring device for use in a producing well is set forth It includes a sonde having upper and lower centralizers to define an annular flow space therearound In the preferred embodiment, a motor driven sensor preferably a piezoelectric combination transmitter and receiver is, included to transmit and then receive ultrasonic pulses They are transmitted downwardly from the housing into fluid flowing in the well Reflective interfaces are defined by material differences Gas bubbles droplets and particles in the fluid flow and phases between oil and water, etc form reflective interfaces to create a scattering effect to transmitted ultrasonic pulses so that a return pulse is formed The pulses encodes fluid flow velocity as a result of the Doppler shift

Pulsed ultrasonic doppler borehole fluid measuring apparatus

This disclosure is directed to a detector system for use in measuring while drilling (MWD) equipment. It comprises preferably duplicate chambers positioned to one another and mounted in a MWD system where they are subject to the same shock and vibration. The shock and vibration impinge on the two chambers, and cause two output signals to be formed. The two output signals are applied to a differential amplifier so that the microphonic portion of the signal is cancelled. This then leads to a differential output signal which carries in it the signals representing nuclear events detected by the similar or duplicate detector means. Alternately, a single chamber can be used if it is provided with two anode wires and they are connected to the differential amplifier for signal cancellation.

Method for discriminating microphonic noise in proportional counters

An optical rotary joint for use in a well logging cable is set forth in the preferred and illustrated embodiment capable of transferring two or more data streams traveling along two or more optical fiber channels. The rotary joint is constructed with a stationary portion and a coacting rotary portion. A first channel of data is delivered to an optical fiber transmitted coaxially of the stationary and rotary sides of the apparatus, transfer across the rotational plane between the two components being accomplished by opposing centrally located, concentrically arranged, coacting optical lenses. A second data channel transmitted through a second optical fiber is delivered to a lens system which converts the light into a cylinder of light coaxial with the first channel and which surrounds the optical management for the first channel. All channels other than the first channel thus are converted into coaxial hollow cylinders of light. These cylinders of light are transmitted between facing lens systems in the rotary and stationary sides of the apparatus.

Multichannel optical rotary joint for well logging usage

An optical fiber quick disconnect mechanism comprised of left and right separable portions is set forth. One portion is ideally anchored to a pressure isolating bulkhead at a drilled passage which is provided with threads partly along its length; a fixed portion of the quick disconnect mechanism can be anchored there. This enables division of an optical fiber into left and right portions which provide an optical path therethrough. The left and right optical portions are supported by alignment capillaries and the detachable portion of the equipment includes a threaded body which joins to the fixed portion.

Quick disconnect fiber optic feedthrough for well borehole usage

For use in a downhole oil well logging tool which is enclosed in a sonde and suspended on an armored logging cable, a means for measuring the macroscopic thermal neutron capture cross section of the borehole fluid is set forth. In the preferred embodiment, a neutron source adjacent to a neutron detector is positioned in a sonde. The entire surrounding region in the well borehole is used as a sample chamber. Fast neutrons from the source after collision with fluid nuclei impinge on the detector which provides an output signal which is indicative of neutron flux. The count rate is most significantly dependent on the thermal neutron capture cross section of the borehole fluid. An additional detector can likewise be spaced farther from the neutron source and provide an alternate count rate. Through the use of two detectors, minor perturbations induced by changes in the environment outside the borehole can be compensated. The neutron capture cross section can be determined for the borehole fluid. Preferably, the sonde is supported for traveling along a cased well on centralizers to control the volume of fluid that is in the immediate vicinity of the neutron source which fluid may be characterized as falling within a test chamber region defined by the case 12.

Randy Gold

Papers

Pulsed ultrasonic doppler borehole fluid measuring apparatus

Method for discriminating microphonic noise in proportional counters

Multichannel optical rotary joint for well logging usage

Quick disconnect fiber optic feedthrough for well borehole usage

Logging tool for measuring the macroscopic thermal neutron capture cross section of borehole fluids