Patent ID: 9121252
Filing Date: 2015-09-01
Classification: E21B

Abstract:
1. An apparatus to provide time-delayed injection of pressurized fluid from a well casing into a geological formation comprising: a housing with openings that allows fluid to pass through the openings to the formation; a piston configured to cover the openings in a closed position; a pressure activated opening device configured to be in pressure communication with the piston; a restrictive means configured to be connected to the pressure activated opening device; means for moving the piston to an open position leaving the openings uncovered; whereby, as a pressure of the pressurized fluid activates the pressure activated opening device, the restrictive means substantially impedes a flow of the pressurized fluid that moves the piston, and as the piston moves from the closed position into a high pressure chamber comprising a hydraulic fluid, the piston is restrained in movement by a passage of the hydraulic fluid from the high pressure chamber into a low pressure chamber through a liquid flow restrictor, and the movement of the piston from the closed position to the open position is delayed by a predetermined metering time.