Hydrocarbon accumulation characteristics and enrichment controls of LB block in Llanos Basin

Based on the analysis of hydrocarbon generation, migration and accumulation, the controlling elements and pattern of reservoirs in the LB block of the Llanos Basin were summarized. The influencing factors for local hydrocarbon enrichment were identified, and favorable exploration targets were predicted. The LB block had a good potential for hydrocarbon migration and accumulation. In the major reservoir (the Carbonera Formation), multiple sets of reservoir-cap assemblages developed. Traps included faulted noses and faulted anticlines associa-ted with normal faults. Structure and reservoir were the main controlling factors of hydrocarbon accumulation. Hydrocarbon migrated laterally along massive sandstones in the C7 section of the Carbonera Formation. Firstly, they accumulated in structural traps in the C7 section, and then partially migrated upwards into the C5 section through faults and accumulated in structural and lithologic traps adjacent to the faults at the bottom of C5. Local hydrocarbon enrichment was affected by various factors, such as tectonic background, trap amplitude and reservoir quality.Low-amplitude faulted anticline reservoirs developed far away from faults in the C7 section and lithologic updip pinch-out reservoirs in the downthrown side of faults in the C5 section were predicted.