Patent ID: 7735556

Claim:
A method for building a plug in a horizontal wellbore, the method comprising the steps of: (a) pumping a fracturing fluid into the horizontal wellbore; (b) suspending ultra lightweight proppant within a fluid pill, the ultra lightweight proppant being capable of remaining suspended in various types of fluids; (c) pumping a displacement fluid down the wellbore to displace the fluid pill; (d) varying a pumping rate of the displacement fluid such that at least one fracture in a zone of the horizontal wellbore is allowed to partially close, the ultra lightweight proppant remaining suspended within the fluid pill; (e) pumping the fluid down the horizontal wellbore to slowly displace the fluid pill after the at least one fracture in the zone has partially closed; and (f) at least partially preventing the ultra lightweight proppant from entering the at least one fracture in the zone, wherein the ultra lightweight proppant bridges off forming a plug within the wellbore.