The Development of Hydraulic Flow Units and their Petrographic/Petrophysical Properties

Howard King

Hydraulic flow units are related to deposition and initial lithification. At lithification primary fluid flow paths are developed. These pathways remain as unique sedimentary features and may be open or closed depending on diagenetic events. Flow units are multidimensional in form. They are composed of sets of clinoforms. Clinoforms also form the flow units bounding surfaces. Unique sets of clinoforms, comprising a flow unit, are characterized by inter-related petrophysical and petrographic properties developed throughout the rocks diagenetic history.

These petrographic/petrophysical relationships are imitable within an individual flow unit but inimitable from flow unit to flow unit. Thus, hydraulic flow units can often be recognized by a number of methods. Several of these methods need to be put into place to ensure continuity and that the hydraulic flow unit does exist as an entity.

Methods of recognition are:

1. Common authigenic pore mineralogy.
2. Characteristic pore morphology.
3. Trends in mineralization.
4. Unique porosity/permeability cross plot slopes.
5. Unique suite of capillary pressure curves which are associated by shape and also nest or seat into each other.
6. Related pore size distribution patterns.
7. Related saturation profiles.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995