关键词: 非达西渗流, 滞留油藏, 向斜成藏理论, 低超低渗透储层, 非常规, 致密油, 成藏新理论

Abstract:

 The conventional petroleum geology theory is suitable for the reservoirs with high permeability and fluid flows obeying Darcy law with buoyancy effect mechanism, and oil and gas are situated at the high position of structure and sand body, and they are always structural reservoirs. But this theory does not apply to the reservoirs with low and ultralow permeability or tight reservoirs where fluid flows obey non-Darcy law, and oil and gas cannot be separated by gravitation. On the condition of overpressure expulsion, flow primarily migrates as episodic expulsion manner, the oil droplets gradually deform and pass through the pore throats as nonDarcy flow. This low speed migration must lead to the stagnant mechanism that oil stagnates and accumulates in the lower area and form continuous reservoirs. This stagnation accumulation reservoirs will cause the phenomenon that oil accumulates in anticline area, or oil accumulates at low position of slope but water accumulates at high position, which is the oil-gas inversion. The stagnation accumulation reservoirs which have no structure, no lithology traps, no unified temperaturepressure systems and oilwater contacts have changed the traditional trap exploration method, expanded the concept of reservoir, and formed the fundamental theory for the research field such as reservoirs with low and ultralow permeability and unconventional and tight reservoirs. Theory of petroleum accumulation in syncline is an important supplement to traditional petroleum geology. This theory expands the exploration area, changes the exploration target from high position of structure to low position, extremely increases the petroleum source and is regarded as important guiding principle for the petroleum exploration and development.

Key words: non-Darcy flow, stagnation accumulation reservoir, petroleum accumulation theory in syncline, reservoirs with low and ultralow permeability, unconventional reservoirs, tight reservoirs, new petroleum accumulation theory