METHOD AND DEVICE FOR LIQUID INJECTION IN RESERVOIR Russian patent published in 2008 - IPC E21B43/27 E21B33/13 

FIELD: well drilling in underground reservoir for oil and gas obtaining.

SUBSTANCE: device for processing liquid injection in underground reservoir comprises drilling string having at least one plugging means to isolate selected well section from another one. Flow string additionally includes liquid flow passage having inlet communicated with opened area in selected well section. Each plugging means includes inflatable member, which may be shifted between radially retracted state and radially expanded state. Drilling string additionally has means for selectively communicating inflating channel with liquid passage. Said means includes tubular bush located in inner surface of tubular drilling string part and sliding between closed and opened positions relatively orifice made in tubular part wall. Processing liquid injection method involves bringing drilling string into operation in decreased hydrostatic well pressure regime to advance thereof to underground reservoir zone to be treated; stopping drilling operation when said underground reservoir zone reaches predetermined well section selected by sealing means arrangement in drilling string; moving sealing means from radially retracted state to radially expanded state; injecting processing liquid flow via liquid passage and outlet orifice in selected well section and in reservoir zone to be treated, wherein remainder well section is under decreased hydrostatic pressure.

EFFECT: possibility of processing liquid introduction in reservoir under increased hydrostatic pressure in well bore without processing liquid mixing with drilling mud along with decreased hydrostatic pressure outside zone to be treated.

13 cl, 8 dwg