DEVICE FOR SECONDARY DRILLING-IN OF PRODUCTIVE STRATUM Russian patent published in 2004 - IPC

FIELD: oil-and-gas production industry; secondary drilling-in of productive stratum to depth of penetration of filter of drilling mud, plugging-back and other technological fluids.

SUBSTANCE: proposed device includes tubular housing with drilling unit inside it, drill, drill flushing unit, mechanism for securing housing to wall of well bore, cassette with drill and drilling bushes for adding the length of drill and suspension of housing in form of logging cable. Drill is made in form of hollow rod with mill at the end. Drilling unit is provided with elastic diaphragm having central hole whose diameter is lesser than diameter of drilling bush rotating in synchronism with bush during its operation. Mechanisms for securing the housing are mounted above and under drilling unit symmetrically to it. Drill and drilling bushes are pressed from below by means of spring. Cassette is built in lower portion of device and partially located in drilling unit for alignment of axes of drill and spindle of drilling unit. Mill has ellipsoid section.

EFFECT: simplified construction; enhanced reliability.

2 cl, 3 dwg