核磁共振增强扩散方法在复杂储集层流体识别中的应用

核磁共振增强扩散流体性质识别技术将长回波间隔条件下横向弛豫时间谱中水扩散弛豫时间右侧出现的明显弛豫信号作为储集层含油的直接指示。均匀磁场下进行的变回波间隔实验与梯度场下进行的相同实验结果有较大差异,只有后者才能模拟P型核磁测井仪器的实际测井结果,指导测井解释。借鉴国外成功的梯度磁场变回波间隔实验结果,讨论了核磁共振增强扩散技术的适应范围,并指出应用中还应注意钻井液侵入问题,尽量采用及时测井资料。初步应用表明,该项技术可作为电阻率方法的有益补充,在渤海湾盆地复杂油水层的识别中取得了很好的应用效果。图6参12

Enhanced diffusion theory of nuclear magnetic resonance (NMR) and its application to fluid identification of complex reservoirs

Enhanced diffusion theory of NMR to identify the type of reservoir fluid utilizes the obvious relaxation signal located right after the diffusion relaxation item of water as the direct indicator of oil existence in reservoirs. The result of NMR experiments by changing TEs in the uniform magnetic field is greatly different from that in the gradient field. Only the latter can simulate the result of MRIL-Prime tools and guide well logging interpretation. According to foreign successful NMR experiments with multiple TEs in a gradient magnetic field, we discuss the application range of this method and point out that it's better to use timely logging data in order to decrease the effect of drilling mud invasion. Preliminary applications prove it very effective, as a valuable supplement of the resistivity logging method, in the determination of fluid type in complex reservoirs of the Bohai Bay Basin.