Trapped gas saturations in carbonate formations

TLDR: In this article, trapped gas saturation values in selected carbonate reservoirs were investigated, and samples covering the porosity and permeability range within each field were tested Cores from Smackover reservoirs located within 4 states were included to examine differences in trapped gas which might occur within a carbonate deposited over a large geographical area The trapped gas varied with initial gas in place and with rock type.

Abstract: Trapped gas saturations existing after gas displacement by wetting phase imbibition are presented for selected carbonate reservoirs Formations representing various rock types were investigated, and samples covering the porosity and permeability range within each field were tested Cores from Smackover reservoirs located within 4 states were included to examine differences in trapped gas which might occur within a carbonate deposited over a large geographical area The trapped gas varied with initial gas in place and with rock type With gas in place of 80% of pore space, trapped gas values ranged from a low of 23% of pore space in Type II chalk to a maximum of 69% in the Type I limestone evaluated Correlation of trapped gas saturation values was attempted using several approaches, but none was entirely satisfactory No relationship with permeability was found within most reservoirs, or between different reservoirs Within a given field, trapped gas at a common initial gas saturation typically increased as porosity decreased