| 摘要 |
<p>PURPOSE: To measure the stratum in a zone that is intruded by a mud filtrate accurately and quantitatively by using a measurement pad with an electrode array that is in contact with the wall of a drilled hole on the surface. CONSTITUTION: The stratum inspection device 10 has an electronic cartridge 16 that controls the operation of the device 10, preliminarily processes a measurement signal, and remotely interfaces to a data sampling circuit on the ground and an arm 18 that can advance or retreat for carrying a measurement pad 20 that can be engaged to the wall of a drilled hole 11 at an end part. First, a measurement current is supplied from the central electrode of an electrode array and the measurement current in an intrusion zone 23 located inside the drilled hole 11 at the reverse side of the measurement pad 20 is received. Then, the measurement current is focused radially in a first direction that is vertical or parallel to the axis of the drilled hole 11 by an active focusing system. Also, a measurement current is focused radially along a second direction that is vertical to one direction that is parallel or vertical to the axis of the drilled hole 11 of a passive focusing system. Then, a measurement current value is measured to determine a specific resistance.</p> |
