US 11,933,136 B2
Dissolvable balls for activation and deactivation of a circulating sub apparatus
Jothibasu Ramasamy, Dhahran (SA); Chinthaka Pasan Gooneratne, Dhahran (SA); and Jianhui Xu, Dhahran (SA)
Assigned to Saudi Arabian Oil Company, Dhahran (SA)
Filed by Saudi Arabian Oil Company, Dhahran (SA)
Filed on Dec. 1, 2021, as Appl. No. 17/539,609.
Prior Publication US 2023/0167710 A1, Jun. 1, 2023
Int. Cl. E21B 34/10 (2006.01); E21B 21/10 (2006.01); E21B 34/06 (2006.01)
CPC E21B 34/063 (2013.01) [E21B 21/103 (2013.01); E21B 34/10 (2013.01); E21B 2200/06 (2020.05)] 17 Claims
OG exemplary drawing
 
1. A method for mitigating lost circulation while drilling a well, the method comprising:
opening a port of a circulating sub, including:
dropping a ball into a drill pipe containing a downhole fluid, in which the port is defined in a wall of the drill pipe; and
seating the ball on an actuator slidably disposed concentrically within the drill pipe, in which seating the ball on the actuator causes motion of the actuator relative to the drill pipe to open the port; establishing circulation by pumping a lost circulation material slurry through the drill pipe, out of the port, and into an annulus of a wellbore exterior to the drill pipe, bypassing a bottom hole assembly comprising a drill bit;
in response to establishing circulation, closing the port of the circulating sub, including:
introducing a solvent different from the downhole fluid and the lost circulation material slurry into the drill pipe, in which a solubility of the ball in the solvent is greater than a solubility of the ball in the downhole fluid and the lost circulation material slurry; and
degrading the ball in the solvent, in which the degrading of the ball deactivates the circulating sub causing the port to close.