METHOD OF RECOVERY OF PASSABILITY OF OPEN HORIZONTAL WELLBORE Russian patent published in 2015 - IPC E21B21/00 

FIELD: mining.

SUBSTANCE: at implementation of the method on the wellhead with open horizontal wellbore collect the bottom-hole assembly is assembled which consists of (bottom-up) a bit, a right branch pipe 4 m long and a calibrator, the bottom-hole assembly is lowered into the well at the string end to the beginning of open wellbore interval, simultaneous rotation of the string with the rotation frequency 20 rpm and direct washing along the string of drilling pipes are performed with the flow rate 10 l/s, then by axial movement of the string with reference to the open wellbore at a speed no more than 20 m/h the wellbore passability is recovered. Before each jointing of the string of pipes the washing by one and a half volume of the string of drilling pipes is performed with triple working-out in places of screwing and slacking-off with the bottom-hole assembly reciprocation, the string with the bottom-hole assembly is extracted from the well, at the string end the spherical funnel with a gauge is lowered down to the interval of open horizontal wellbore, the backflow with the flow rate 7 l/s is performed, with simultaneous movement of the string with the maximum speed 0.5 m/s with reference to the open wellbore. Before jointing of each drilling pipe the washing by one and a half volume of the string of drilling pipes with the bottom-hole assembly reciprocation to the length of the drilling pipe is performed, avoiding slacking-off of the string of drilling pipes in the well above 5 t from own weight, after washing of an open horizontal wellbore the string of drilling pipes with the spherical funnel and the gauge template is extracted from the well.

EFFECT: improvement of reliability and efficiency of passability recovery.

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