Abstract: On the basis of the real geological model of Pingqiaoblock, Ansai oilfie1d, dozens of heterogeneous simu1ationmodels were estab1ished through scientific abstraction.Westudied in detai1 some basic factors concerning reservoirengineering in integrated horizontal we1l waterflooding inlow permeability reservoirs.They include the relationshipbetween the direction of horizontal we1lbore and that ofartificial fractures, the number and lengthes of artificialfractures and the reasonable well patterns.