最新的流體描述法采用擴散編碼脈沖序列組成的數(shù)據(jù)系列。為了提供連續(xù)的流體(水、油和氣)飽和度和油黏度曲線，要對脈沖序列進(jìn)行同時反演。這些數(shù)據(jù)系列對擴散系數(shù)(D)和流體弛豫時間都敏感。分子擴散是流體中隨機的分子熱運動。擴散編碼序列是CPMG序列的改進(jìn)，其中一個或兩個回波之間間隔增大。在磁場梯度中，分子擴散縮短了T2弛豫時間，這種效應(yīng)在擴散碼序列的回波間隔增大期間被放大。通過采集具有不同長回波間隔的擴散編碼數(shù)據(jù)便可直接測量分子擴散率。
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