ABSTRACT: Borehole Fracture Classification Using Image Analysis
LINCECUM, VAL J., and T. A. MA, Atlas Wireline Services, Western Atlas International, Houston, TX
Effective evaluation and management in fractured reservoirs requires early recognition of the natural fracture system and a systematic approach to the gathering and subsequent analysis of data. This paper describes a need to classify subsurface fractures based on borehole image analysis and introduces group classifications based on origin and appearance.
Before the development of imaging devices, formation evaluation in fractured reservoirs has been at best qualitative. Fractures were also observed and classified in whole cores, although at surface conditions. Advancements in borehole imaging now allows us to observe fracturing in the subsurface environment under near in-situ stress conditions. These fractures can be described by their characteristic shapes and oriented for principal stress relationships.
Included in this discussion are illustrations of both drilling induced and natural fractures as they occur at the borehole face in both vertical and horizontal wellbores. Both groups of fractures have impacts on subsurface fluid flow and each play a significant role in production characteristics. Methods of determining fracture width will also be discussed.
AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)