Many kinds of reservoir damages have encounteredwhen drilling in the low permeability reservoirs,including solid particle invasion,sensitive damages induced by liquid invasion,liquid entrap in narrow pore throat,plugging by emulsions and so on,in which,the liquid entrap is the main damage type.

The author made a profound analysis about the so-called Shanbei hydrodynamically trapped oil pool according to the theoretical conditions for the formation and preservation of a hydrodynamic trap and the practical hydrodynamic conditions of Shanbei oil pool,and found that even if the sandstone reservoir beds of Huoshaogou Format.