关键词: 动力圈闭, 非达西流, 启动压力梯度, 超压, 甜点, 低渗透致密储集层

Abstract:

In low permeability-tight reservoir,fluid filtration belongs to the non-Darcy flow. Only when the pressure gradient comes to the starting pressure gradient, can the filtration occur. Overpressure is a predominant dynamic force for hydrocarbon migration and accumulation in low permeability-tight reservoir, and “dynamic trap” is the most important action for hydrocarbons overpressure-charged into low permeability-tight reservoirs to form accumulations and also a three-dimensional space for hydrocarbons to be relented and accumulated. “Dynamic trap” is quite different from the conventional trap with mid-high permeability reservoir such as structural trap, stratigraphic trap and lithologic trap. The difference shows not only in charging dynamic force, filtration way, but also in oil-gas-water relation, trap shape and distribution. Advantages to form a “dynamic trap” are believed as sources and reservoirs are superimposed or interbedded in large scale, overpressures of hydrocarbon generation can act on reservoirs next to sources and hydrocarbons migrate in short distance in a pore-fracture network, which finally lead to the formation of large-scale continuous hydrocarbon-bearing interval. The “dynamic trap”, located in the superimposition part of the source “sweet point” and the reservoir “sweet point”，is the most easliy to form unconventional reservoirs. The presentation of the “dynamic trap” concept hopes to supply new thinking for enriching petroleum geology theory, deepening hydrocarbon accumulation’s classification and prospecting unconventional hydrocarbon accumulations.

Key words: dynamic trap, non-Darcy flow, starting pressure gradient, overpressure, sweet point, low permeability-tight reservoir