Abstract: Methods of mitigating lost circulation while drilling a wellbore. The methods include circulating a drilling mud to a downhole end of the wellbore via a drill string and, during the circulating, drilling the wellbore with a drill bit of the drill string. The methods also include detecting lost circulation within the wellbore while drilling the wellbore and include providing a monomer solution to the wellbore. The methods further include providing a catalyst to the wellbore responsive to detecting the lost circulation event and combining the monomer solution and the catalyst to polymerize a monomer from the monomer solution, within the wellbore, and forming a viscous plug within the wellbore. Subsequent to the combining, the methods include flowing at least a portion of the viscous plug within the wellbore and into a zone of lost circulation that extends within a subsurface region.

Abstract: Methods of mitigating lost circulation while drilling a wellbore. The methods include circulating a drilling mud to a downhole end of the wellbore via a drill string and, during the circulating, drilling the wellbore with a drill bit of the drill string. The methods also include detecting lost circulation within the wellbore while drilling the wellbore and include providing a monomer solution to the wellbore. The methods further include providing a catalyst to the wellbore responsive to detecting the lost circulation event and combining the monomer solution and the catalyst to polymerize a monomer from the monomer solution, within the wellbore, and forming a viscous plug within the wellbore. Subsequent to the combining, the methods include flowing at least a portion of the viscous plug within the wellbore and into a zone of lost circulation that extends within a subsurface region.

Abstract: Apparatus, compositions, and methods for creating polymer plugs in wellbores and/or for enhancing wellbore stability, comprising: a flow control device such as a blowout preventer on a wellbore; a control fluid aperture fluidly connected with the wellbore for introducing a control fluid and/or a plug-forming agent such as a polymer, monomer, resinous, and/or crosslinkable material, through a control fluid aperture and into the primary throughbore while wellbore blowout fluid flows through the wellbore; and optionally, a weighted fluid aperture positioned in the wellbore conduit below the control fluid aperture for introducing a weighted fluid or another fluid or plug-forming agent into the wellbore. Exemplary plug-forming agents include dicyclopentadiene and norborene, and exemplary catalysts include Grubbs catalysts. The polymer plugs also may be utilized to hydraulic sealing within wellbores, such as during P&A and drilling operations for providing wellbore stability.