电磁波组合测井资料在水淹层解释中的应用

兆赫级测量频率的电磁波测井提供了电导率和介电常数两类信息，有助于解决岩层经过长期注水开发后的水洗状况识别困难的问题。针对大庆油田电磁波组合测井仪，利用均匀介质磁偶极子电磁场理论考察分析发现，60 MHz相位差同时受岩层介电常数和电导率的影响，而2 MHz相位差值主要受岩层电导率的影响。同时，合理构建了由相位差曲线快速反演计算介电常数和电导率的公式：首先，针对2 MHz相位差曲线，建立已知介电常数，反演计算电导率的公式；其次，以深侧向电阻率为已知输入，建立由60 MHz相位差曲线反演计算介电常数的公式。针对两口密闭取心井进行反演计算，计算出的介电常数及电导率很好地反映了岩层水洗状况。利用反演计算的电导率和介电常数建立岩层水洗程度识别标准，符合率达到87.5%,为污水回注岩层的剩余油有效识别创造了条件。

Application of electromagnetic wave combination logging data in flooding reservoir interpretation

Electromagnetic wave logging with the measurement frequency of megahertz provides two kinds of information of conductivity and permittivity, which is conducive to resolving the issue of identifying the washed condition of rock formations after long-term waterflood development. Based on the electromagnetic wave combination logging instrument of Daqing oilfield, using the electromagnetic field theory of uniform medium magnetic dipole, reveals that the phase difference of 60MHz is affected by the dielectric constant and conductivity of the stratum, while the phase difference of 2MHz is mainly affected by the conductivity of the stratum. Simutaneously, a reasonable formula for calculating permittivity and conductivity from phase difference curve is established. First, for 2MHz phase difference curve, a formula for calculating conductivity with known permittivity is established. Secondly, with the deep lateral resistivity as a known input, permittivity inversion formulas are established based on the 60MHz phase difference curve. The permittivity and conductivity calculated by inverse calculation for two closed coring Wells can well reflect the condition of rock washing. The identification standard of rock washing degree was established by using the conductivity and dielectric constant of inversion calculation, and the coincidence rate reached 87.5%, which created conditions for effective identification of the remaining oil in the rock of sewage injection.