Abstract:
A drill pipe identification system automatically provides an identification number for each drill pipe as the drill pipe is being lowered into or withdrawn from the well. The system has a SAW identification device which is mounted in a cylindrical cavity which is formed within a tool joint of each section of drill pipe. The cavity has an aperture leading to the exterior of the tool joint to allow radio frequency signals to be received and reradiated. The SAW device receives signals from a transmitter and receiver, modulates the signals and reradiates them in a manner that corresponds to an encoded number in the SAW device.
Abstract:
Apparatus for seismic surveying a borehole by simultaneously measuring seismic signals at a plurality of elevations within the borehole. A resilient tubular member is filled with a liquid and the length of the tubular member is divided into several adjacent series arranged chambers. A sensor for receiving the seismic signal is placed within each chamber, and means are provided for measuring and storing the signal received by each of the sensors. The sensors are suspended within the tubular member by a stress member, and the stress member is suspended from a bulkhead which divides the adjacent chambers, and which isolates the chambers one from the other. This arrangement of parts provides a unique structure which enables geologizing a borehole seismically in a new and unobvious manner.
Abstract:
For use in an acoustic logging tool, an apparatus which digitizes simultaneously obtained acoustic signals is set forth in the preferred and illustrated embodiment. The device cooperates with N acoustic receivers in a sonde. After an acoustic pulse is transmitted, data is observed at all N acoustic receivers. This apparatus comprises a multiplexer which is connected to the several receivers. The several input signals are multiplexed, thereafter input to a digital data converter forming a procession of output digital words, and the words are stored in a selected order in a digital data buffer. They are delivered to the surface through a telemetry transmitter at a slower rate than the rate at which the data is created. In addition, a transmitter monitor is included. This provides a signal alternately digitized for a specified interval to enable coordination of the data reduction from the acoustic receivers in contrast with the timing of the transmitted acoustic pulse.
Abstract:
An apparatus and method for the measuring the transverse dimensions of a hole such as in an oil well including a sonde on which an electro-acoustic transducer is mounted in an offcentered position in relation to the axis of the sonde. This transducer has two opposite active faces so as to simultaneously transmit acoustic pulses in diametrically opposite diections from the sonde. When the sonde is centered in the hole, the transducer picks up the echoes retransmitted by the wall of the hole in the two directions, at different times. A recording is made of these times and preferably also of an indication of the amplitude of each of these echoes to obtain both a diameter measurement and an indication of the condition of the hole surface. Several transducers are provided, superposed and oriented along various diameters distributed around the axis of the sonde.
Abstract:
A device for anchoring a probe in a well by opening at least one arm pivotable with respect to the body of the probe by a spring moving a rod in a guide housing of the body and operating arms. In a closed position of the arm, the rod is locked by a bolt and a hydraulic fluid contained in a chamber and maintained at the same pressure as the pressure external to the probe is used for driving the bolt, when the pressure of this fluid is applied thereto intermittently by an electromagnetic valve.
Abstract:
Dip measurements and investigation of geological formations traversed by a deviated borehole is carried out by means of an apparatus comprising a measuring sonde and a cartridge connected to a cable. The sonde carries four measuring pads regularly distributed by means of articulated arms which keep the pads parallel to the axis of the sonde. The opposite arms are forced to stay symmetrical in relation to the sonde.The sonde is connected to the cartridge so that its axis can depart angularly from the axis of the cartridge, enabling the latter to rest on the borehole wall. The pads have a length smaller than twice the transverse dimension D of the sonde.
Abstract:
A signal amplifier system for use in a downhole logging system wherein a signal transmitter is mounted in a sonde suspended on a logging cable thousands of feet into a borehole. Variable slew rate amplifiers connected to a differential amplifier are set forth. Preferably, programmable amplifiers having a gain determined by a driving current are used. Two such amplifiers are connected to the input signal, and they are driven by different current sources. The output signals are summed at a differential amplifier. Through the use of different slew rates, the incoming signal is amplified by the two programmable amplifiers and the outputs of the two amplifiers are then subtracted from one another. Signals which pass equally through both programmable amplifiers (due to slew rates which do not cause limiting) thus are subtracted from each other. Faster rise time signal pulses are amplified by different gains; the differential of the two amplified signals (having differing gain rates) enables noise reduction at the differential amplifier output. The differential output signal is reduced in noise amplitude.
Abstract:
An acoustic borehole tool consists of two components: A first component containing power supplies, signal processing and control electronics and a sidewall locking mechanism. A second component includes a seismic sensor and a clamping device for pressing the sensor against the sidewall of a borehole. The weight of the second component is a small fraction of the weight of the first component so that the force exerted by the clamping device is less than a preselected limiting value and so that the clamping force/mass ratio may reach large value without danger of destroying the borehole.
Abstract:
A method for finding the distance between a blowout well and a relief well. The method comprises measuring the acoustic noise in the relief well at two or more locations and then calculating the distance to the blowout well.
Abstract:
Apparatus for shear wave logging of formations adjacent a borehole wherein a tubular apparatus is specifically constructed for sympathetic movement with the borehole in response to low frequency horizontal shear waves. The apparatus consists of tubular frame structure with end members including housings for rigid seating of orthogonal pairs of horizontal wave detectors. Outer sleeve structure may be utilized for buoyancy adjustment.