公开(公告)号：US06437564B1

公开(公告)日：2002-08-20

申请号：US09846971

申请日：2001-05-01

申请人： Gregory Boris Itskovich ,  David Beard ,  Arcady Reiderman

发明人： Gregory Boris Itskovich ,  David Beard ,  Arcady Reiderman

IPC分类号： G01V300

CPC分类号： G01V3/32 ,  G01N24/081

摘要： The static magnetic field of a permanent magnet used in an NMR tool moves with the tool. NMR measurements made with a moving tool are affected by incomplete polarization of the nuclear spins in the region where the Larmor frequency of static field matches the RF signal frequency. Simulation results show that the in-phase and quadrature components of spin echo signals are affected by the velocity of lateral motion of a logging tool in a borehole. A phase drift indicator is obtained by summing the quadrature and in-phase components over a window and taking the ratio of the windowed sums. The phase drift indicator shows an increase with time. In a tool with a gradient magnetic field, the phase drift indicator increases with time even for no tool motion. The reduction in magnitude of spin echo data due to tool motion alone may be obtained by comparing the magnitude of simulated echoes with and without tool motion.

摘要翻译： 用于NMR工具的永磁体的静磁场随工具移动。 使用移动工具进行的NMR测量受静态场拉莫尔频率与RF信号频率匹配的区域中的核自旋的不完全极化的影响。 模拟结果表明，自旋回波信号的同相和正交分量受井眼测井工具横向运动速度的影响。 通过对窗口上的正交和同相分量进行求和并获取窗口和的比值来获得相位漂移指示符。 相位漂移指示器随着时间的推移而增加。 在具有梯度磁场的工具中，即使没有刀具运动，相位漂移指示器随时间增加。 可以通过比较具有和不具有工具运动的模拟回波的幅度来获得由于单独的工具运动引起的自旋回波数据的幅度的减小。

公开(公告)号：US06353322B1

公开(公告)日：2002-03-05

申请号：US09094220

申请日：1998-06-09

申请人： Leonty Abraham Tabarovsky ,  Gregory Boris Itskovich

发明人： Leonty Abraham Tabarovsky ,  Gregory Boris Itskovich

IPC分类号： G01V320

CPC分类号： G01V3/20

摘要： A method for determining the resistivity of earth formations penetrated by a wellbore. Electrical current is imparted to the wellbore and the earth formations from a first electrode located on a mandrel disposed in the wellbore. The electrical current is returned at a second electrode on the mandrel at a spaced apart location from the first electrode. Voltage differences are measured between a first pair and a second pair of electrodes located on the mandrel between the first and the second electrodes. Circuits used to measure the voltage differences are adjusted until the measured voltage difference between the second pair is substantially the same as the measured voltage difference between the first pair. Then the electrical current is returned to an electrode at the earth's surface or other location distal from the first electrode, and measuring the voltage differences is repeated. A difference of the voltage differences is then calculated. The difference of voltage difference represents current leakage into the earth formation substantially unaffected by irregularities in the wall of the wellbore or drift in the circuits. The current leakage is inversely related to the resistivity of the earth formations.

摘要翻译： 一种确定井筒渗透的地层电阻率的方法。 从位于设置在井筒中的心轴上的第一电极向井筒和地层施加电流。 电流在与第一电极间隔开的位置处在心轴上的第二电极处返回。 在位于第一和第二电极之间的心轴上的第一对电极和第二对电极之间测量电压差。 用于测量电压差的电路被调整直到第二对之间的测量电压差基本上与第一对之间的测量电压差相同。 然后电流返回到地球表面或远离第一电极的其他位置处的电极，并且重复测量电压差。 然后计算电压差的差。 电压差的差异表示电流泄漏到地层中，基本上不受井筒壁的不规则或电路中的漂移的影响。 电流泄漏与地层电阻率成反比。