利用测井方法识别复杂油气储层的流体性质

地球物理测井能识别储层流体性质的前提条件是油、气、水的物理参数存在差异。但是,油、气、水层能否识别还取决于储层的岩性、孔隙结构等因素。根据电阻率法识别孔隙结构复杂储层流体性质时,主要受孔隙度指数m的影响,利用微电阻率成像测井与常规孔隙度测井相结合的方法可有效地确定m值。此外,针对低阻油气层形成的原因不同,可用不同的识别方法:对于薄互层通过改进数据采集方式解决;对于因孔隙结构和泥质影响造成的低阻油气层,则利用改进的解释模型解决。核磁测井识别流体性质的技术也取得不少进展,在原差谱法的基础上,先后发展完善了时间域分析法、移谱法、强化扩散法以及剪辑扩散法等。

Problem and advance on the fluid typing for complex reservoirs using well log

The difference of physical parameters in oil-gas-water are premise that geophysical well log can be used for fluid typing. However, the identification of oil-gas-water layers is also dependent on lithology and pore structure of reservoir rocks. Porosity index M is an important parameter when electrical resistivity is used for the fluid typing of reservoir rocks with complex pore structure. The M value may be estimated by the micro-resistivity imaging logs, combined with conventional porosity logs. Low-resistivity reservoirs are caused by different reasons, therefore the different methods are needed for their fluid typing. The improved data collection pattern is suitable for a thin-interbedded reservoir; the improved interpretation model is suitable for the low-resistivity reservoirs caused by pore structure and mud content. In recent years, some progresses have been made in fluid typing using NMR logs. On the basis of original differential spectra, many new methods, such as time-domain analysis method, mobile spectra method, diffusion-forcing method and diffusion-editing method, have been successively developed and improved.