Abstract: A resistivity measurement while drilling (MWD) device, including: a transmitting module arranged on an outer surface of a drill collar, for generating an induced current between the drill collar and surrounding formation by inductive coupling; a receiving electrode group including at least two electrodes, for receiving a measured current that reaches the electrode from the induced current through corresponding formation, two electrodes in the receiving electrode group being multiplexing electrodes; a resistivity calculation module configured to be connected to all or a part of the electrodes in the receiving electrode group in a measurement mode of the resistivity MWD device, to calculate the measured current received by a corresponding electrode and obtain resistivity of formation corresponding to the corresponding electrode; and a data transmission module configured to be connected to the multiplexing electrodes in a transmission mode of the resistivity MWD device, for transmitting calculated resistivity to

Abstract: A resistivity measurement while drilling (MWD) device, including: a transmitting module arranged on an outer surface of a drill collar, for generating an induced current between the drill collar and surrounding formation by inductive coupling; a receiving electrode group including at least two electrodes, for receiving a measured current that reaches the electrode from the induced current through corresponding formation, two electrodes in the receiving electrode group being multiplexing electrodes; a resistivity calculation module configured to be connected to all or a part of the electrodes in the receiving electrode group in a measurement mode of the resistivity MWD device, to calculate the measured current received by a corresponding electrode and obtain resistivity of formation corresponding to the corresponding electrode; and a data transmission module configured to be connected to the multiplexing electrodes in a transmission mode of the resistivity MWD device, for transmitting calculated resistivity to

Abstract: Disclosed is a data transmission system and a method for transmission of downhole measurement data to the ground. The system includes a drill string mounted with a logging while drilling measurement tool, and a throw while drilling section, which accommodates a micromemory. The throw while drilling section includes a housing which is mounted outside of the drill string as a sleeve to form a clearance space therebetween; a control circuit; and a wireless transceiver. The throw while drilling section releases, under function of a micromemory release instruction transmitted by the control circuit, the micromemory loaded with the downhole measurement data to the ground.

Abstract: Disclosed is a data transmission system and a method for transmission of downhole measurement data to the ground. The system includes a drill string mounted with a logging while drilling measurement tool, and a throw while drilling section, which accommodates a micromemory. The throw while drilling section includes a housing which is mounted outside of the drill string as a sleeve to form a clearance space therebetween; a control circuit; and a wireless transceiver. The throw while drilling section releases, under function of a micromemory release instruction transmitted by the control circuit, the micromemory loaded with the downhole measurement data to the ground.

Abstract: A row bar having a plurality of slider forming areas collocated and slider cutting areas formed between two adjacent slider forming areas respectively, the slider forming areas are eventually cut into individual sliders along the slider cutting areas respectively, each slider having a pole tip embedded therein and an air bearing surface pattern on an air bearing surface facing to a disk, and at least a regular measuring pattern with straight line is formed on one of the slider cutting areas, to serve as a frame of reference for measuring the position of the pole tip and the air bearing surface pattern. The present invention can improve the measuring accuracy, decrease the measuring error and, in turn, improve the performance of the slider.