Abstract: A method for sealing a wellbore around a pipe placed within it is disclosed. The method includes providing to a wellbore site a pre-mixed pre-polymer sealant solution and storing the sealant until use. The sealant material may be injected into wellbore in the space exterior to the pipe so that the sealant material contacts at least some portion of the pipe exterior surface and the wellbore interior surface. Upon injection, the sealant material may begin to cure from contact with moisture in the ground, the curing causing the sealant material to release a gas and form a sealing foam into the extra-pipe space. The sealing foam may then be permitted to cure to form a flexible and stable seal.