Significance of High-Wax Oil Variability to Pacific Rim Exploration and Production

Robert M. K. Carlson and Stephen R. Jacobson

High-Wax oils are a class of paraffinic crudes that occur widely in Pacific Rim petroleum systems. New analytical technologies, particularly High Temperature Gas Chromatography (HTGC) show unexpected variations in the molecular weight ranges and concentrations of paraffin waxes within this class of crudes, These variations are source and maturity-related, providing paleoenvironmental and generative information useful to exploration. Paleoenvironmental factors revealed by high-wax oil HTGC source signatures can also help interpret the potential for nearby reservoirs. Furthermore, variations in wax compositions affect flow and organic scale-forming properties that impact the productior economics of these oils.

Lacustrine-sourced high-wax oils contain broad distributions of paraffin waxes ranging from C₂₀ to C₆₀ or higher. Various algae appear to be the source of higher molecular weight waxes in these oils. Paleoenvironmental factors such as water salinities and paleoclimate, affect wax compositions of resulting lacustrine high-wax oils. Other terrestrial-sourced oils generated by paralic or nearshore marine source rocks show high concentrations of C₂₅ to C₃₅ waxes but much lower distributions of higher molecular weight waxes. These highwax oils appear to contain waxes derived principally from terrestrial, higher plant materials.

Results for high-wax petroleum systems in Australia, Indonesia, the Philippines and China illustrate these conclusions with examples ranging in age from Carboniferous-Permian to late Tertiary.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California