Abstract:

During the high watercut stage of proven old oil fields in China, reservoir study has changed from the evaluation of highquality reservoirs to interlayer and plane reservoir heterogeneity which affects the conflict between oil reservoir injection and production. The key issue for interlayer heterogeneity study has transferred from evaluation of traditional heterogeneity parameters to reservoir architecture, where the core of reservoir architecture research is to figure out the geometric shape of sandbodies with different genies and different directions and the distribution characteristics of interbeds; while the core of planar heterogeneity research is to choose scientific and reasonable parameters for accurate calculation and quantitative mapping according to reservoir scale, depositional genesis and characteristics, especially the differences between lithologic characteristics and thickness. All the above formed a new method for reservoir characterization, which can be summarized as “led by microfacies, guided by facies sequence, genesis quantification and integration of plane and profile”. It can better reflect the function and effect of reservoir characterization, which was to identify the genetic characteristics and distribution rules of different reservoirs (sublayers or sandbodies in development) to figure out the problems in oilfield development. The function of reservoir characterization is to approach the geological reality in maximum scale by scientific genesis classification, while the effect of reservoir characterization is to predict the distribution rules of subsurface oil/gas and to provide reliable and synthetic guidance for effective development.

Key words: reservoir architecture, led by microfacies, guided by facies sequence, isopic facies but different sandbody, simultaneous and isochronization