二维核磁共振测井时序与反演算法实验研究  

Study of sequence and inversion algorithm in 2D NMR well logging

作　　者：宋公仆[1] 吴磊[2] 程晶晶[3] 

机构地区：[1]中海油田服务股份有限公司油田技术研究院,北京101149 [2]北京理工大学化工与环境学院,北京100081 [3]华中科技大学自动化学院,武汉430074

出　　处：《国外电子测量技术》2013年第9期38-41,共4页Foreign Electronic Measurement Technology

基　　金：湖北省自然科学基金(2009CDB053)

摘　　要：本文提出了一种"改进型CPMG DE"二维核磁共振测井序列,同时获取地层流体扩散系数D和横向弛豫时间T2,克服了"改变回波间隔,测量多组CPMG自旋回波"时序在测量长扩散时间方面的缺陷;并结合奇异值分解(SVD)与Tikhonov正则化算法提出了一种与该时序对应的反演解释方法,极大地减少了反演过程的计算量和复杂性,有效获取流体扩散-弛豫(D-T2)二维分布。数值模拟显示,对同时含有稠油和束缚水的地层,当原始信号SNR>40dB时,该算法可有效区分稠油和束缚水。在自行研发的二维核磁测井仪上的初步实验室研究表明,本文设计时序与算法可有效获取CuSO4溶液的二维分布。An improved CPMG DE sequences for tow-dimensional NMR well logging were proposed in this thesis.The new method could measure both the diffusion and relaxation.And it overcomes the shortcoming in long diffusion-time measurements,which is existed in the previous CPMG sequences with different echo spacing.Beside this,an inversion algorithm base on SVD and Tikhonov regulaization was designed for the modified CPMG DE sequences to obtain the （D-T2） distribution,which is efficient in reducing the computational and algorithmic complexity.Furthermore,the modified sequences and inversion algorithm＇s performance were demonstrated through simulation data.When the SNR is more than 40dB,heavy oil and bound water could be differentiate clearly.And the experiment taken on own R＆D 2D NMR logging tool shows that the algorithm could get CuSO4 solution＇s （D-T2） distribution effectively.

关 键 词：二维核磁共振测井 扩散-弛豫二维分布 扩散-编辑脉冲序列 奇异值分解 TIKHONOV正则化 

分 类 号：P3[天文地球—地球物理学]