核磁共振录井可动流体t_2截止值确定方法

Discussion on determining method for movable fluid cutoff t_2

可动流体t2截止值在核磁共振录井测量中是一项重要的参数,它与储集层岩石孔隙大小有关,而与孔隙度和渗透率之间均没有很好的相关性。离心标定法是准确确定可动流体t2截止值的有效方法,但该方法不能满足现场核磁共振录井快速测量分析的需要。针对此问题,在阐述确定可动流体t2截止值影响因素和室内离心标定法的基础上,对辽河油田可动流体t2截止值归类结果进行了分析探讨,结果表明t2弛豫谱图形态经验判断法、岩性经验判断法是现场快速确定可动流体t2截止值的有效方法。该方法为辽河油田有效应用核磁共振录井技术提供了技术保证,也为其他油田确定可动流体t2截止值提供了参照依据和途径。

Movable fluid cutoff t2 is an important parameter in NMR(nuclear magnetic resonance) logging measurement,which has something to do with the sizes of reservoir rock porosity but has no good relationship with porosity and permeability.Centrifugal calibrating method is the effective way for accurately determining movable fluid cutoff t2,but it can't meet the need of fast measuring and analyzing on wellsite NMR logging.Dealing with this problem on the basis of stating the affecting factors of movable fluid cutoff t2 and indoor centrifugal calibrating method,the author analyzes and discusses the classified result of movable fluid cutoff t2 in Liaohe Oilfield.The result showed that the experience judgment method of relaxation spectrum form and lithology method are the effective methods for fast determining movable fluid cutoff t2 on wellsite,which provide the technical secure for effectively using NMR logging technology in Liaohe Oilfield and meanwhile also provide the comparable basis and feasible way for determining movable fluid cutoff t2 for other oilfields.