一种新型井下偏心核磁共振测井仪探测器设计与实现

Design and Implementation of a New Probe for Eccentric Downhole NMR Logging Tool

核磁共振测井技术作为同时评价储层孔隙特征和流体识别的方法,具有独特的优越性。在实际应用中,井下居中型核磁共振测井仪探测深度受到井眼尺寸的影响,尤其当井眼钻井液电导率较高时,仪器将无法采集到可靠的有用信号。井下偏心核磁共振测井仪可有效解决上述问题。介绍了一种新型的井下偏心核磁共振测井仪探测器结构,通过数值模拟技术对探测器结构进行优化,并完成了实物制作。通过对探测器加工工艺探索,有效降低了天线涡流损耗和振铃的影响,并成功在实验水箱中获取到了核磁共振回波信号。

NMR logging technology has unique advantages as the only method to simultaneously evaluate reservoir pore characteristics and fluid identification.In practical applications,the radial investigation depth of centered downhole nuclear magnetic logging tools is affected by the size of the wellbore,especially when the conductivity of the wellbore mud is high,the probe will not be able to receive reliable useful signals.Eccentric downhole NMR logging tools can effectively solve the above problems.This paper introduces a new type of probe structure for eccentric downhole NMR logging tools.The structure of the probe was optimized by numerical simulation technology and the physical production was completed.By exploring the processing technology of the probe,the effect of eddy current loss and ringing of the antenna are effectively reduced,and the nuclear magnetic resonance echo signals are successfully obtained in the water tank.