--> --> ABSTRACT: What Are Unconventional Resources? A Simple Definition Using Viscosity and Permeability, by Cander, Harris ; #90142 (2012)
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What Are Previous HitUnconventionalNext Hit Previous HitResourcesNext Hit? A Simple Definition Using Viscosity and Permeability

Cander, Harris *1
(1) Exploration and Production, BP, Houston, TX.

There is no formal definition of “Previous HitunconventionalNext Hit Previous HitresourcesNext Hit” despite the fact that Previous HitunconventionalNext Hit Previous HitresourcesNext Hit are the most active petroleum play in North America. Meckel and Thomasson, Previous Hit2008Next Hit, defined Previous HitunconventionalNext Hit Previous HitresourcesNext Hit using purely a permeability threshold (< 0.1 md). Yet, coal bed methane plays are considered Previous HitunconventionalNext Hit and many have permeabilities exceeding 1 md over large portions of the fairway (ex: San Juan Basin, Powder River Basin). Other workers have defined Previous HitunconventionalNext Hit Previous HitresourcesNext Hit based on an interpretation of the petroleum system and have stated that Previous HitunconventionalNext Hit Previous HitresourcesNext Hit are “continuous” or “basin centered” and lack traditional traps. While some have restricted the term to product type (i.e. Previous HitunconventionalNext Hit gas), many shale and tight sand plays have gas, wet gas, and oil fairways and all can be considered Previous HitunconventionalNext Hit. Heavy oil and oil sands are also Previous HitunconventionalNext Hit Previous HitresourcesNext Hit and many of these deposits are in reservoirs with permeability exceeding 500 md. Thus, Previous HitunconventionalNext Hit Previous HitresourcesNext Hit include both low and high permeability reservoirs with both low and high viscosity fluids. Previous definitions have not accounted for all phases of petroleum in all types of reservoirs in all types of petroleum systems.

This paper proposes a simple graphical definition that incorporates properties of both the rocks and their fluids. All petroleum reservoirs can be plotted on a graph of viscosity versus permeability (both in log scale). On this graph, conventional Previous HitresourcesNext Hit all plot in the lower right quadrant, regardless of fluid phase. All Previous HitunconventionalNext Hit Previous HitresourcesNext Hit plot outside this quadrant due to a low ratio of permeability to viscosity. Previous HitUnconventionalNext Hit Previous HitresourcesNext Hit are thus defined as those petroleum reservoirs whose permeability/viscosity ratio requires use of technology to alter either the rock permeability or the fluid viscosity in order to produce the petroleum at commercially competitive rates. Conversely, conventional Previous HitresourcesTop are those that can be produced commercially without altering permeability or viscosity. This simple graphical definition avoids the pitfalls inherent in a petroleum system interpretation (i.e. basin centered or self-sourced versus migrated petroleum). The graphical definition accommodates and delineates tight gas, tight oil, shale gas, shale oil, heavy oil, coal bed methane, and even offshore reservoirs with low k/viscosity ratios.

 

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California