Evaluation methodology of lithologic exploration areas in rift basins: A case from the Bohai Bay Basin

Abstract

Based on the analysis about the main controlling factors of the formation and enrichment of lithologic hydrocarbon reservoirs of sandy conglomerate in the Bohai Bay Basin, and combined with qualitative and quantitative analysis, a classified evaluation mode was established including four factors that are tectonic setting, sedimentary environment, reservoirs and hydrocarbon source rocks. In the evaluation of geologic settings of one rift basin, the authors analyzed and compared the geologic conditions, hydrocarbon bearing and exploratory results of five types of structural zones and three types of sedimentary systems. In the reservoir evaluation, an evaluation item of the reservoir structure was added including six styles and evaluation grades. Combining the classified evaluation of the four factors with the routine analysis of exploration target areas, an evaluation standard of lithologic traps in rift basins was constructed, which is useful to evaluate lithologic targets in rift basins of eastern China. Key words: Bohai Bay Basin, rift basin, lithologic reservoir, sedimentary facies, reservoir structure, target area evaluation