A method for stimulating a formation comprising: providing a tubular member in a wellbore of a subterranean formation, the tubular member being capable of fluid flow therethrough and having at least one burst disk assembly, each burst disk assembly comprising: a burstable disk (20a,148) positioned within a port in a wall of the tubular member, the port remaining closed prior to rupture of the burstable disk (20a,148) at a burst pressure threshold; and a cap positioned within the wall between the burstable disk (20a,148) and the wellbore, spaced from the burstable disk (20a,148) for forming a chamber therebetween, the chamber containing air and having a pressure, the cap preventing pressure outside the tubular member from bursting the burstable disk (20a,148); flowing fluid through the tubular member so as to reach a burst pressure threshold for rupturing the burstable disk (20a,148) of the at least one burst disk assembly; flowing fluid through the chamber for displacing the cap toward the wellbore for flowing fluids therethrough to the wellbore; the method characterized by: locating a treatment tubing in the tubular member for delivery of the fluid to the burstable disk (20a,148), and thereby forming an annulus between the treatment tubing and the tubular member; isolating the annulus to thereby isolate an interval which straddles the or each burst disk assembly; pumping fluid through the treatment tubing to the isolated interval for increasing the pressure in the isolated interval until the pressure reaches the burst pressure threshold; rupturing the burstable disk (20a,148) of the at least one burst disk assembly in the isolated interval; and flowing treatment fluid through the ruptured burst disk assembly for treating the formation at the isolated interval. providing a tubular member in a wellbore of a subterranean formation, the tubular member being capable of fluid flow therethrough and having at least one burst disk assembly, each burst disk assembly comprising: a burstable disk (20a,148) positioned within a port in a wall of the tubular member, the port remaining closed prior to rupture of the burstable disk (20a,148) at a burst pressure threshold; and a cap positioned within the wall between the burstable disk (20a,148) and the wellbore, spaced from the burstable disk (20a,148) for forming a chamber therebetween, the chamber containing air and having a pressure, the cap preventing pressure outside the tubular member from bursting the burstable disk (20a,148); a burstable disk (20a,148) positioned within a port in a wall of the tubular member, the port remaining closed prior to rupture of the burstable disk (20a,148) at a burst pressure threshold; and a cap positioned within the wall between the burstable disk (20a,148) and the wellbore, spaced from the burstable disk (20a,148) for forming a chamber therebetween, the chamber containing air and having a pressure, the cap preventing pressure outside the tubular member from bursting the burstable disk (20a,148); flowing fluid through the tubular member so as to reach a burst pressure threshold for rupturing the burstable disk (20a,148) of the at least one burst disk assembly; flowing fluid through the chamber for displacing the cap toward the wellbore for flowing fluids therethrough to the wellbore; the method characterized by: locating a treatment tubing in the tubular member for delivery of the fluid to the burstable disk (20a,148), and thereby forming an annulus between the treatment tubing and the tubular member; isolating the annulus to thereby isolate an interval which straddles the or each burst disk assembly; pumping fluid through the treatment tubing to the isolated interval for increasing the pressure in the isolated interval until the pressure reaches the burst pressure threshold; rupturing the burstable disk (20a,148) of the at least one burst disk assembly in the isolated interval; and flowing treatment fluid through the ruptured burst disk assembly for treating the formation at the isolated interval. locating a treatment tubing in the tubular member for delivery of the fluid to the burstable disk (20a,148), and thereby forming an annulus between the treatment tubing and the tubular member; isolating the annulus to thereby isolate an interval which straddles the or each burst disk assembly; pumping fluid through the treatment tubing to the isolated interval for increasing the pressure in the isolated interval until the pressure reaches the burst pressure threshold; rupturing the burstable disk (20a,148) of the at least one burst disk assembly in the isolated interval; and flowing treatment fluid through the ruptured burst disk assembly for treating the formation at the isolated interval.