国外电子测量技术
國外電子測量技術
국외전자측량기술
FOREIGN ELECTRONIC MEASUREMENT TECHNOLOGY
2015年
8期
61-65
,共5页
核磁共振测井仪%脉冲序列%储能电路%扳转角
覈磁共振測井儀%脈遲序列%儲能電路%扳轉角
핵자공진측정의%맥충서렬%저능전로%반전각
NMR well logging tools%pulse sequence%energy storage circuit%tip angle
核磁共振测井仪通过发射高能量射频脉冲来实现氢核磁矩的扳转和重聚,并以此获取地层信息。受测井电缆瞬时功率传输能力限制,脉冲发射时直流高压大幅下降,使得扳转角和重聚角不满足要求,无法有效激发氢核。根据核磁共振测井仪射频脉冲特点,在对其能量需求分析的基础上,利用负反馈原理设计一种储能电路,为射频脉冲提供足够功率及稳定的高压输出。在现场应用中,Phi_A 及 RA T IO_B的实时曲线表明该电路能够为射频脉冲发射提供可靠保障。
覈磁共振測井儀通過髮射高能量射頻脈遲來實現氫覈磁矩的扳轉和重聚,併以此穫取地層信息。受測井電纜瞬時功率傳輸能力限製,脈遲髮射時直流高壓大幅下降,使得扳轉角和重聚角不滿足要求,無法有效激髮氫覈。根據覈磁共振測井儀射頻脈遲特點,在對其能量需求分析的基礎上,利用負反饋原理設計一種儲能電路,為射頻脈遲提供足夠功率及穩定的高壓輸齣。在現場應用中,Phi_A 及 RA T IO_B的實時麯線錶明該電路能夠為射頻脈遲髮射提供可靠保障。
핵자공진측정의통과발사고능량사빈맥충래실현경핵자구적반전화중취,병이차획취지층신식。수측정전람순시공솔전수능력한제,맥충발사시직류고압대폭하강,사득반전각화중취각불만족요구,무법유효격발경핵。근거핵자공진측정의사빈맥충특점,재대기능량수구분석적기출상,이용부반궤원리설계일충저능전로,위사빈맥충제공족구공솔급은정적고압수출。재현장응용중,Phi_A 급 RA T IO_B적실시곡선표명해전로능구위사빈맥충발사제공가고보장。
NMR well logging tools achieve the tipping and refocusing of magnetic moment of hydrogen nucleus through high‐energy RF pulse and acquire formation information .Limited to the logging cable instantaneous pow er transfer capa‐bility ,DC high voltage is sharply dropped while emitting pulse .So tip angle and flip angle aren’t satisfactory ,which makes it impossible to effectively excite hydrogen nucleus .According to the characteristics of RF pulse of NMR well log‐ging tools ,this thesis designs a kind of energy storage circuit to provide enough pow er and stable high‐voltage output for RF pulse ,based on the analysis of energy demand and the principle of negative feedback .In the field application ,the real‐time curve of Phi_A and RATIO_B show that the circuit successfully ensures the RF pulse emission .