Registration tool of resistivity, and the registration tool during drilling, which measures the resistivity of a formation

摘要

"Registration tool of resistivity, and the registration tool during drilling, which measures the resistivity of a formation.A resistivity tool for use in a system LWD, includes an arrangement of transmitter with multiple transmitters (t ~ 1 ~ t ~ 2 ~ t ~ 3 ~) positioned above a pair of receivers (R ~ 1 ~,R ~ 2 ~). The transmitters (t ~ 1 ~ t ~ 2 ~ t ~ 3 ~) are selectively energized, making an induced current in the collar of the tool.The axial current in the collar of the tool is measured by the pair of receivers (R ~ 1 ~ R ~ 2 ~) to determine the amount of current flowing in the formation between the receivers (R ~ 1 ~ R ~ 2 ~).From this, the resistivity of formation can be measured for each transmitter to provide multiple depths of investigation.Several discrete electrodes (500) are positioned between the two receptors (R ~ 1 ~ R ~ 2 ~) to allow the image of boring hole and azimutalmente sensitive resistivity readings.Based on the voltage level at each discrete electrodes and on the amount of current flowing in the formation.