基于PNN测井技术的复杂储层流体识别与饱和度计算

套管井中通常使用的饱和度测井方法大都建立在伽马射线探测的基础上,很难适用于油田高含水中后开发期。脉冲中子-中子(Pulse Neutron-Neutron,PNN)测井是通过直接测量热中子强度来计算剩余油饱和度的技术,在低矿化度、低孔隙度地层中,由于单位时间里被俘获的热中子少,没有被俘获的热中子多,因此饱和度测量精度高,而且不受伽马本底值的影响。首先介绍了PNN测井仪器的工作原理,然后讨论了PNN测井的数据处理方法与饱和度计算方法,最后通过两个油田的应用实例,证明PNN测井技术适用于低矿化度、低孔隙度储层以及水淹层的流体识别与饱和度计算。

Fluid identification and saturation calculation of complex reservoir based on PNN logging

At present,saturation logging techniques in cased-hole are almost based on gamma ray detection,which are difficult to suitable to the high water saturation fields.Pulse Neutron-Neutron (PNN) logging is a new production logging technology,which directly records thermal neutron rates to calculate remained oil saturation.In the formation with low salinity and low porosity,the thermal neutron seized in unit time is little,so the precision of saturation measurement is high and not affected by gamma background level.Firstly,the operating principles of PNN logging instrument was introduced.Then,the data processing method and saturation calculation method of PNN logging were discussed.Finally,two application examples were displayed,which showed that PNN logging was suitable to low salinity and low porosity reservoir,as well as to the fluid identification and saturation calculation of water flooded reservoir.