我国核磁共振测井应用中的若干重要问题

Some Important Issues for NMR Logging Applications in China

核磁共振(NMR)测井在中国的应用已经有10余年的历史。它提供的地层信息的丰富性,远多于其他任何单项测井方法。对于复杂岩性、特殊岩性,它常常是少数几种有效的重要方法之一;对于束缚水引起的低电阻率油气藏,它是必不可少的方法;是迄今为止唯一能够提供比较合理的地层渗透率的测井方法;对于深部气层,当天然气孔隙体积比较大时,它的显示十分明显;在稠油以及水淹层,有一定的经验关系存在;对原油黏度以及毛管压力曲线等信息也有较好的反映,等等。由于或是使用条件的不适应,或是使用方法的不恰当,或是技术本身的不完善,NMR应用也存在或出现过不少问题。它求出的孔隙度时常偏低,有时也偏高;求出的束缚水对地区或地层的依赖性比较强;求出的渗透率还没有得到油藏专家的广泛应用;在流体识别方面还有比较大的随意性和不确定性,等等。深入研究这些问题,对提高核磁共振测井技术应用效果,挖掘其应用潜力等都有重要意义。试图从实际效果和技术适应性等几个方面,探讨中国核磁共振测井应用中存在的一些常见问题,以促进该项技术的正确应用。

NMR logging has been applied in China reservoir evaluation for more than a decade. And it has made very positive contributions to Chings complicated formation evaluation and to the development of China well logging technology. There are many good things and bad things experienced. Issues related to NMR porosity, fluid-typing, irreducible water, permeability, tool feasibilities, job design, and data qtlality control are reviewed and discussed in details. The aim is to provide an outline and guides to NMR logging applications in various saturations based on author＇s theoretical considerations and application experiences.