公开(公告)号：US5463320A

公开(公告)日：1995-10-31

申请号：US259849

申请日：1994-06-15

申请人： Stephen D. Bonner ,  Richard A. Rosthal ,  Abdullah A. Bagersh ,  Martin G. Luling ,  Jacques A. Jundt

发明人： Stephen D. Bonner ,  Richard A. Rosthal ,  Abdullah A. Bagersh ,  Martin G. Luling ,  Jacques A. Jundt

IPC分类号： G01V3/20 ,  G01V3/18

CPC分类号： G01V3/20

摘要： A logging tool for use in determining the resistivity of an underground formation surrounding a borehole comprises a mandrel with two transmitters spaced apart thereon, each serving to establish a current in the mandrel and in the underground formation. A series of electrodes are spaced along the body between the transmitters and sensors, located at each electrode, measure radial current flow along a path from the mandrel to the underground formation via a respective electrode. Sensors also provide the axial current flowing along the whole mandrel and at positions corresponding to each electrode. A method of determining the formation resistivity includes the steps of measuring the radial currents R.sub.1 R.sub.2 from the mandrel to the formation via each electrode and obtaining the axial currents M.sub.01 M.sub.02 along the mandrel at each electrode due to each transmitter; measuring the total axial current M.sub.12 along the mandrel from the first or second transmitter and deriving the resistivity of the formation from the radial focused current R.sub.c for each electrode according to the relationship R.sub.c =1/M.sub.21 (M.sub.02 R.sub.1 +M.sub.01 R.sub.2).

摘要翻译： 用于确定围绕钻孔的地下地层的电阻率的测井工具包括具有间隔开的两个发射器的心轴，每个用于在心轴和地下地层中建立电流。 位于每个电极处的发射器和传感器之间的一系列电极沿主体间隔开，测量沿着从心轴经由相应电极到地下地层的路径的径向电流。 传感器还提供沿着整个心轴和对应于每个电极的位置流动的轴向电流。 确定地层电阻率的方法包括以下步骤：通过每个电极测量从心轴到地层的径向电流R1R2，并且由于每个发射器获得每个电极处的心轴处的轴向电流M01M02; 根据Rc = 1 / M21（M02R1 + M01R2）的关系，从第一或第二发射器测量沿着心轴的总轴向电流M12，并从每个电极的径向聚焦电流Rc导出地层的电阻率。