地层波速的电缆和随钻动电测井实验研究

基于孔隙介质动电效应的测量方法在油气勘探领域有着巨大的潜在应用价值.本文针对理论预测的随钻动电测井可削弱钻铤波对地层声波干扰的问题,设计了室内随钻动电测井实验装置和测量系统,并在小尺寸砂岩模型井中开展了随钻动电测井实验研究.为了突出随钻动电测井技术的特点,本文先在砂岩模型井中进行了电缆声波测井和电缆动电测井实验测量,获得了地层声波的传播速度.然后又在同一模型井中进行了随钻声波测井和随钻动电测井实验,记录了这两种情况下的测井全波波形,比较了电缆声波/动电测井和随钻声波/动电测井的差异性,并进一步分析了钻铤波和井中动电转换信号的传播特性.本文还通过随钻动电测井的时域波形提取到被测地层的纵横波速度,从实验角度验证了随钻动电测井技术测量地层波速的可行性.此外,本文实验结果对随钻动电测井的仪器设计及现场测量也有参考意义.

Electrokinetic measurements of formation velocities with wireline seismoelectric logging and seismoelectric logging while drilling

The electrokinetic measurements have been suggested to be a potential method for oil and gas exploration. To analyze the problem that collar waves can disturb the measurements of formation waves in acoustic logging while drilling, a scaled seismoelectric logging while drilling detector and a set of experimental systems are designed based on the electrokinetic effect. Four kinds of logging measurements (acoustic wireline logging, acoustic logging while drilling, seismoelectric wireline logging, and seismoelectric logging while drilling) are conducted on borehole models in the lab. The wave-fields of four methods are recorded and analyzed. Then the differences of full waveforms in these four measurements are compared, and the propagation characteristics of collar waves and seismoelectric waves are further studied according to the experimental data. In addition, the formation velocities of P and S waves are calculated from the time domain waveforms of seismoelectric logging while drilling, which agree well with the theoretical results and also verify the feasibility of seismoelectric logging while drilling. Our results are also helpful for the tool design of the seismoelectric logging while drilling and the field measurements.