Abstract: The exploration of subtle or non-structural reservoir is of great challenge for recognition of its non-structural trap. Microbial oil survey technique (MOST) is effective for such reservoir recognition, for it depends on the relationship between oils in the trap and microbial concentration in soil above it for exploration of hydrocarbon fluid. The successful application of MOST to Qaidam basin, Fort Worth basin and Osage county in Oklahoma shows that high-yielding lithologic and structural reservoirs have been discovered. This paper points out that there is a great need for modification or perfection in such four aspects as light hydrocarbon micro-percolation principle, affecting factor and detecting technology of microbe as well as related geological interpretation.

Key words: Microbial oil survey technique, subtle reservoir, non-structural reservoir, lithologic gas reservoir, synclinal reservoir