Pressure actuated ported sub for subterranean cement completions

#The field of the invention is a pressure actuated sleeve used in a cementing assembly that is responsive to tubing pressure to open a port and more particularly a sleeve that is associated with a piston where the piston is not referenced to annulus pressure when actuated by selective communication of tubing pressure to one side with the opposed side referenced to a low pressure chamber within the housing.

#Prior sleeves that have been deployed in cementing service have been based on the concept of providing opposed piston areas exposed to tubing pressure that are of different dimensions so that raising the tubing pressure will create a sufficient net force to in theory overcome seal friction and move the sleeve to the open position. One such design is the Halliburton Initiator Sliding Sleeve that has a larger upper seal diameter than a lower seal. Raising tubing pressure creates a net differential force and the piston is allowed to move because there is an atmospheric chamber between the upper and lower seals. The problem is that to get the lower seal to be smaller than the upper seal to create the desired net force in the needed direction, the wall of the sleeve adjacent the lower seal and the atmospheric chamber has to be reduced so that the sleeve can shift while the volume of the atmospheric chamber is reduced.

#The wall of the sleeve in the area of the atmospheric chamber sees substantial differential pressure and can flex or bend. When that happens the sleeve gets stuck and the desired port opening in the housing fails to occur.

#FIG. 1 is a section view of the sleeve in the ports closed position;

#FIG. 2 is the view of FIG. 1 with the sleeve in the ports open position; and

#FIG. 3 is an enlarged view of the rupture disc assembly shown in FIG. 2.

#Referring to FIG. 1, the apparatus has the following components: upper body tubular connection 1; upper ported housing 2; inner shifting sleeve 3; port isolation seals 4; upper internal polished bore 5; fluid communication ports 6; sleeve shear screw shoulder 7; shear screws 8; upper internal bore piston seals 9; intermediate internal polished bore 10; upper pressure testing port 11; upper atmospheric chamber 12; burst disk load nut 13; burst disk load ring 14; burst disk or chemically responsive barrier 15; intermediate internal bore piston seals and piston 16; sleeve lock ring retention groove 17; lower internal polished bore 18; lower atmospheric chamber 19; sleeve lock ring retainer 20; sleeve lock ring 21; body seals 22; body connection 23; body set screws 24; lower sleeve polished bore 25; lower pressure testing port 26; lower external rod piston seals 27; lower body 28; and lower body tubular connection 29.

#The valve is run in open-hole cementable completions just above the float equipment. The valve is connected to the casing through the upper body tubular connection (1) at the top and the lower body tubular connection (29) at the bottom. The structural valve body is made-up of an upper ported housing (2) and lower body (28). Pressure integrity of the valve is maintained with the body seals (22). The body set screws (24) keep the body connection threads (23) from backing out during installation. Between the upper ported housing (2) and the lower body (28) is captured an inner shifting sleeve (3). The inner shifting sleeve (3) has several diameters that create piston areas that generate shifting forces to open the valve. The port isolation seals (4) located on the upper end of the inner shifting sleeve (3) and the upper internal bore piston seals (9) below the fluid communication ports (6) both act to isolate the inside of the valve during and after cementation. The larger intermediate internal bore piston seals (16) are used to drive down the inner shifting sleeve (3) along the lower internal polished bore (18) within the upper ported housing (2), once the burst disk (15) is ruptured. Both sets of seals operate within their respective polished bores (5, 10) within the upper ported housing (2). The lower external rod piston seals (27) located within the lower body (28) act to prevent cement from entering the lower atmospheric chamber (19) and wipe the outside diameter of the lower sleeve polished bore (25) during the opening of the valve. The inner shifting sleeve (3) also has a shoulder (7) that shears the shear screws (8) during the opening shift of the inner sleeve (3). An external sleeve lock ring retention groove (17) is located between the internal bore piston seals (16) and the lower sleeve polished bore (25) diameter. This recess will accept the sleeve lock ring (21) that is retained by the lock ring retainer (20) once the valve had fully opened. The sleeve lock ring (21) will prevent the inner shifting sleeve (3) from closing once the valve has fully opened.

#Between the upper internal bore piston seals (9) and the intermediate internal bore piston seals (16) is created the upper atmospheric chamber (12) which contains air that can be independently tested through the upper pressure test port (11). Between the intermediate internal bore piston seals (16) and the lower external rod piston seals (27) is created a lower atmospheric chamber (19) which also contains air that can be independently tested through a lower pressure testing port (26). A burst disk (15) is held into place within a port located on the outside of the inner shifting sleeve (3) by a load ring (14) and a load nut (13). The burst disk load nut (13) is sized to allow significant torque and load to be transferred into the burst disk (15) prior to installation of the inner shifting sleeve (3) within the valve.