GB545271A - Improvements relating to devices for clearing obstructions from wells or bore holes - Google Patents

Abstract

545,271. Borehole apparatus. CUTHILL, J., and . OIL WELL ENGINEERING CO., Ltd. March 10, 1941, No. 3228. [Class 85] Means for clearing obstructions, such as mud rings left adjacent porous strata, from boreholes comprise a pair of relatively movable parts adapted to be inserted in a drill string and having one or more outwardly directed ports for discharge of fluid, and means for controlling such discharge by relative movement of the parts,.such movement simultaneously permitting a valve to close and thereby stop the flow of fluid to the drill. The device comprises a part 9 having a reduced lower end 10 threaded at 11 to a valve casing 12 containing a ball valve 13; the part 9 fits within a socket part 16 so that splines 20, 20a, normally engage to convey rotation to the drill, the parts being held together by shear pins 2.9 engaging the valve casing. The ends of splines 20 are formed by the V-tips of set screws 21 to facilitate engagement. Threaded to the socket 16 is a holder 32 carrying a stem 35 which normally projects into the valve casing to hold valve 13 from its seat 13a to permit circulating fluid to pass to the drill. If an obstruction is to be removed, an upward pull is applied to part 9 to break shear pins 29 and to expose radial ports 15 therein as in Fig. 3, the ball simultaneously engaging seat 13a to close the passage to the drill, the circulating fluid, acid or oil then discharging through ports 15 on to the obstruction while the part 9 is rotated and reciprocated. If the drill bit cannot be withdrawn, the upper part of the drill string is raises until V-ended splines 23 on the valve casing mesh with splines 20, rotation then breaking the threaded joint 11 to permit removal of the upper part of the string. In another form, Fig. 5, the shear pins 29 are replaced by composite flat springs 37 held by set screws 37a and having turned over upper ends 38 yieldably engaging a groove in the valve casing 12.