WELL BOTTOM PREVENTER Russian patent published in 1996 - IPC

FIELD: well drilling. SUBSTANCE: well bottom PREVENTER includes hollow casing 1 with by-pass channel 2 and flush channel 3 related to pipe string, sealing gland 4 forming chamber 5 together with the casing. The chamber is related to pressure source. Pipe 6 related through cutting member 7 to casing 1 and hollow slide valve 8 with seat 9 for isolating valve and flush channels 10. The pipe has flush channels 12 aligned with flush channels 10 of the slide valve that forms ring cavity 15 with pipe 6. Annular piston 16 and valve sleeve 17 are placed in the annular cavity 15 so as to be moved along the axis. Valve sleeve 17 is related through cutting member 18 to the casing. Pressure source is placed in the annular cavity between piston 16 and sleeve 17 and made in the form of a charge of slowly burning substance 19 with electric detonator 20. Inflammation of the charge and initiating substance 19 occurs when magnetic sleeve 31 takes casing 1 port opposite magnetically controlled contacts 23. Sealing gland is expanded under liquid pressure being displaced by piston 16 that moves down under the pressure of gases generating as a result of burning charge 19. With gas pressure kept growing pins 18 are cut off and sleeve 17 comes up to open flush channels of casing 3, pipes 12 and slide valve 10. As a result drilling mud is replaced over pipe driver. Isolating valve 32 is installed to flush space under the pipe driver. The valve takes seat 9 of the slide valve and moves it down. Pipe string space is open through channel 13 below isolating valve. By-pass channel 2 is open to the space beyond one under the pipe driver. EFFECT: high efficiency. 2 cl, 4 dwg