超深随钻方位电磁波测井探测特性及参数敏感性分析

本文给出超深随钻方位电磁波测井的仪器天线设计及探测模式信号定义;分析各探测模式的探测性能及对地层电阻率、倾角及各向异性的表征能力;定义方位角、井斜角及地层电阻率的敏感性函数,定性分析不同模式对地层参数的敏感性.研究结果表明,超深随钻方位电磁波测井各探测模式具有不同探测特性,探测模式Ⅰ利用对称设计识别地层边界,消除井斜角...

Detection performance and sensitivity of logging-while-drilling extra-deep azimuthal resistivity measurement

This paper presents the antenna design and the signal definition of logging-while-drilling Extra-Deep Azimuthal Resistivity Measurement (EDARM) and systematic investigations on the detection performance and the sensitivity of formation parameters. The detection capabilities and characterization capabilities of each mode are discussed. The sensitivity function is proposed to describe the measurement properties of azimuthal, dipping angle and resistivity. A qualitative analysis is made to the sensitivity of detection mode to formation parameters to provide support for data analysis and processing. The results show that the detection modes of EDARM have distinct detection characteristics. Mode I adopts the symmetric configuration of signal components, which eliminates the effect of dipping angle and resistivity anisotropy in detecting the bed boundary. In the different formation resistivity conditions, optimizing the operation frequency and spacing permits to enhance the detection range of the instrument for advancing adjust the well trajectory. Mode Ⅱ, by contrast, utilizes the anti-symmetric manner of defining to strengthen the sensitivity of the dipping angle and resistivity anisotropy. According to the sensitivity analysis, the mode Ⅱ mainly reflects the sensitivity to a single parameter in different dipping angles and azimuths. Also, it is particularly sensitive to the change of resistivity when the dipping angle is 60°. Mode Ⅲ has no azimuth sensitivity at any dipping angle, based on the characteristics, which can effectively obtain formation resistivity and is the least affected by the vertical resistivity in horizontal wells. In mode IV, the sensitivity distributeion shows the positive and negative sensitivities changing alternately in different azimuths. It can effectively identify the resistivity anisotropy in high-angle deviated and horizontal wells.