Analysis of application effect of hydrocarbon differential accumulation theory——Taking Huanghekou Depression as an example

Huanghekou depression is one of the hydrocarbon enriched depressions in Bohai Bay Basin, in which over 20×10⁸ m³ crude oil and over 100×10⁸ m³ gas were found in recent years. The exploration effect is remarkable, but we also have some doubt such as a well drilled in a trap with excellent geological factors turned out to be dry, oil layers mainly existed in some wells and others have more gas layers at similar structures with the same source rocks and oil density at the same depth was different in different wells. This paper tried to solve these questions by using hydrocarbon differential accumulation theory. Firstly, the forming reasons of BZ28-2E empty trap in Huanghekou depression were analyzed and a model of migration was founded, by which BZ29-4 structure was evaluated. Secondly, the distribution area of oil and gas were predicted exactly. It is proved that the petroleum migration in Huanghekou depression was in accord with hydrocarbon differential accumulation theory and it could provide direction for next step exploration.