Pore Occlusion
Solid hydrocarbons or bitumen in variable amounts within Red River reservoirs occluded porosity and reduced permeability. Within medium, non-fabric selective sucrosic dolomites, the bitumen is probably not a problem, although it might be responsible for lower recovery factors than from non-bitumen-bearing sucrosic dolomites. Bitumen occlusion is probably a problem in fabric-selective, cryptocrystalline dolomites or micro-porous dolomites. Anhydrite, calcite, and minor chert replacement are also locally present in Red River reservoirs. These occluding and diagenetic minerals decrease both porosity and permeability.