GB1452272A - Method and means for controlling kicks during operations in a boreholde penetrating subsurface formations - Google Patents

Abstract

1452272 Wells &c SHELL INTERNATIONALE RESEARCH MAATSOHIPPIJ BV 23 Oct 1973 [25 Oct 1972 4 Jan 1973 10 Sept 1973] 49137/72 564/73 and 42472/73 Heading E1F To prevent blow-outs, kicks are controlled during operations with a tubular string in a borehole penetrating subsurface formations by:- stopping the operations, setting blowout preventers and closing the passage through the string, pumping mud down the string to inflate and set a packer slidably carried by the string, stopping pumping of mud, displacing the string relative to the packer to open communication between the string interior and exterior above the packer, releasing the blowout preventers, pumping mud of increased density through the string into the annulus about the string above the packer, stopping pumping of mud and displacing the string to permit the packer to deflate, and resuming operations. In the drilling apparatus shown in Fig. 1 when the kick occurs the mud pumps are stopped, the string is raised and blowout preventers are set. Fluid from the formation flows through holes 25 and up the bore 2 until a valve 20 seats. A sleeve 16 carrying the bit 17 and a valve 18 falls under gravity to seat the valve 18 so that mud pumped down the bore passes through ducts 10 to set the packer 4. The packer comprises sleeves 5, 6 slidable on the string, and connected by an elastic sleeve 7. After the string is raised relative to the packer, mud passes out through the ducts 10 into the annulus and the density of the mud is increased to balance the formation pressure and control the kick. The mud flow is stopped and the string is lowered to permit the packer to deflate so that drilling may be resumed. In the operation of the modification shown in Fig. 2 a fluid damped sleeve 47 is raised by the upward flowing formation fluid to engage a member 54 fixed to a sleeve 45 controlling the ducts 44. When the pumps are restarted the valve system 47, 54 moves downwardly and mud passing through the ducts 44 sets the packer 35. The string is raised relative to the packer to permit the ducts to supply the annulus with weighter mud to balance the formation pressure. The string is lowered to permit the packer to deflate and drilling may be resumed. In a modification of Fig. 2 (Fig. 3, not shown) the sleeve 47 is also controlled by the pressure of fluid in the packer and the member 54 is connected to a valve arranged to control fluid supply to the packer and to control the flow of fluid from the packer to the annulus. In a further modification, the outlet from the packer to control the sleeve is at the lower end of the packer and may be connected to the annulus to permit draining of sediment from the packer.