随钻核磁共振测井仪的关键技术简介

针对随钻核磁共振测井的核心问题即安装在钻具上的仪器的过度震动或侧向运动所导致的核磁测量共振区和极化区的不一致以及内部磁场变化的问题,以哈里伯顿公司的MRIL-WD和斯伦贝谢公司的proVISION随钻核磁共振测井仪为例,介绍了随钻核磁共振测井中所采用的关键技术.MRIL-WD采用对运动不敏感的T1测量技术,而proVISION则采用了改进的T2 CPMG采集技术和实时测量钻杆运动的关键技术.

Brief Introduction of Key Techniques in NMR Logging While Drilling Tool

Aimed at two key problems existed in NMR logging while drilling,i.e.the unconformity between the measurement volume and the magnetization volume,as well as the change of internal magnetic field due to excess vibration and/or lateral motion of logging tool fixed on drilling tool, a brief introduction of key techniques used in NMR logging is illustrated by LWD tools of MRIL-WD of Halliburton and proVISION of Schlumberger.The two problems were resolved successfully in their commercial LWD services with different key techniques: a motion-insensitive T1 measurement technique was applied by MRIL-WD,while an improved T2 CPMG(Carr-Purcell-Meiboom-Gill) pulse-echo sequences and real time BHA(Bottom Hole Assembly) motion measurement technique were adopted by proVISION.