Abstract: A method and apparatus for normalizing an acoustic wellbore tool by correcting measured sector acoustic signals due to changes in pressure and temperature downhole, the method and apparatus comprising an acoustic wellbore tool having at least one monopole transmitter and monopole receiver, and one or more sector transmitters and receivers disposed along the longitudinal axis of the tool, determining the attenuation values of received monopole and sector acoustic signals, determining a correction ratio using an average sector attenuation value and a theoretical attenuation value, and correcting the sector acoustic signals using the correction ratio.

Abstract: A method and apparatus for normalizing an acoustic wellbore tool by correcting measured sector acoustic signals due to changes in pressure and temperature downhole, the method and apparatus comprising an acoustic wellbore tool having at least one monopole transmitter and monopole receiver, and one or more sector transmitters and receivers disposed along the longitudinal axis of the tool, determining the attenuation values of received monopole and sector acoustic signals, determining a correction ratio using an average sector attenuation value and a theoretical attenuation value, and correcting the sector acoustic signals using the correction ratio.

Abstract: Using micro-resistivity techniques, an image of the wall of a borehole can be obtained. A downhole tool stack is provided with plural imaging tools, wherein each imaging tool has a set of pads that deploy radially outward to contact the borehole wall to obtain the image thereof. As the pads deploy outwardly, gaps are formed between the pads. The pads of one tool are circumferentially offset relative to the pads of the other tool so that more complete circumferential coverage of the borehole wall is obtained during the imaging process. Furthermore, an adaptive polling technique is utilized to telemeter the large amounts of data generated by the two imaging tools to the surface. Data is obtained from the imaging tools by polling at a particular rate, which rate is modified depending upon the amount of data generated by the imaging tools.

Abstract: A resistivity logging apparatus has an array of electrodes projecting from imaging pads. The electrodes penetrate nonconductive mud lining the borehole wall. Some of the electrodes are moveable in and out of the pad while others of the electrodes can be fixed. The electrodes, which are arranged in an array along a circumferential portion of the borehole wall, are able to make contact with the borehole wall. Sequencing electronics causes one electrode to be a source, another to be a measuring electrode, with the measurements of source electrode and measuring electrode moving along the array in order to log a circumferential portion of the borehole wall.

Abstract: Using micro-resistivity techniques, an image of the wall of a borehole can be obtained. A downhole tool stack is provided with plural imaging tools, wherein each imaging tool has a set of pads that deploy radially outward to contact the borehole wall to obtain the image thereof. As the pads deploy outwardly, gaps are formed between the pads. The pads of one tool are circumferentially offset relative to the pads of the other tool so that more complete circumferential coverage of the borehole wall is obtained during the imaging process. Furthermore, an adaptive polling technique is utilized to telemeter the large amounts of data generated by the two imaging tools to the surface. Data is obtained from the imaging tools by polling at a particular rate, which rate is modified depending upon the amount of data generated by the imaging tools.

Abstract: An induction logging tool is disclosed for utilization in conjunction with surface electronic equipment for measuring a characteristic of subsurface formations. A transmit signal which is comprised of a repetitive sequential series of at least three transmit frequencies is generated by coupling an oscillator to a transmitter coil and a plurality of selectable tuning capacitors. A signal characteristic of the response of the formation to this transmit signal is detected at a receiver coil array and two phase sensitive detectors are then utilized to generate output signals indicative of the magnitude of the X and R components of the formation signal which is in phase with a reference phase signal. The output signal of each phase sensitive detector is then utilized to accurately determine the X and R component of the receiver coil signal for each frequency by nulling the output of the phase sensitive detector utilizing a closed loop conversion circuit which eliminates errors due to phase and gain variations.