Abstract:

 The classical differential accumulation theory describes a process of oil and gas accumulating in a series of correlative traps as that differentially accumulating in a series of traps with better sealed caprocks, or that differentially leaking in a series of traps with bad caprocks. When the new oil or gas recharged into an old reservoir, it should be accumulated by another process of differential accumulation, which is the differential dissolution. The differential dissolution indicates that the new oil and gas would be dissolved as well as entrapped in the preexisting reservoir when they migrate to the traps, i.e., the new oil and gas will accumulate in an old reservoir by a process of dissolution. The hypostasis of differential dissolution is that the molecules of oil and gas dissolve and diffuse differently. The differential dissolution makes oil and gas distributed in the reservoir complicatedly, but with certain regularity: the traps close to the source would be fully filled with dry gas or condensational gas, and those far away from the source would be filled with oil.

Key words: Key words: differential accumulation; differential leaking; differential dissolution; dynamic accumulation