Process for passing carbon dioxide through a cased, cemented and perforated well

Claim 1

In a process for completing and operating a well for production of a liquid from a subterranean reservoir in which a casing string is cemented and perforated and a CO 2 -containing fluid is flowed through a plurality of casing perforations and cement tunnels into or out of the reservoir, an improved process for reducing CO 2 -induced damage of the cement, comprising: injecting a first aqueous liquid which is compatible with the liquid in the well and the reservoir into the casing string prior to the flowing of the CO 2 -containing fluid; flowing the first aqueous liquid into and out of contact with the casing perforations and the cement tunnels to displace debris from the casing perforations and the cement tunnels; injecting into the casing string a volume of an oleogenous liquid which contains a plurality of dissolved epoxy resin-forming components and epoxy resin-curing agents capable of subsequently forming and depositing a cured epoxy resin at the reservoir temperature and has a volume which is not significantly more than enough to fill the casing perforations and the cement tunnels; injecting a second aqueous liquid which is compatible with the liquid in the well and reservoir into the casing string; displacing the oleogenous liquid ahead of the second aqueous liquid so that the oleogenous liquid is driven to fill the casing perforations and the cement tunnels; maintaining the oleogenous liquid at least substantially stationary until a deposition of at least substantially cured epoxy resin has occurred substantially selectively within the casing perforations and the cement tunnels; injecting into the casing string a third aqueous liquid which is compatible with the liquid in the well and reservoir; flowing the third aqueous liquid into and out of contact with the casing perforations and the cement tunnels to displace the resin-forming components which are undeposited; and subsequently flowing the CO 2 -containing fluid through the resin coated casing perforations and the cement tunnels.

Claim 9

A method for protecting a well completion having a cemented and perforated casing string from CO 2 degradation in which casing perforations and cement tunnels are coated after well completion by the method comprising: displacing debris from the casing perforations and the cement tunnels by flowing a well compatible aqueous liquid into and out of contact with the casing perforations and cement tunnels; suspending a retrievable packer with a tail pipe run on a tubing above the highest perforation in the casing; filling the casing perforations and the cement tunnels with an oleogenous liquid solution which includes an epoxy resin based on a glycidylether of bisphenol-A, a polyamine and phenol in an organic solvent and which is capable of subsequently forming and depositing a cured epoxy resin at the reservoir temperature, by chasing a volume of the oleogenous liquid solution, which is not significantly more than enough to fill the casing perforations and cement tunnels, with brine; maintaining the oleogenous liquid solution at least substantially stationary until a deposition of at least substantially cured epoxy resin has occurred substantially selectively within the casing perforations and the cement tunnels; releasing the packer and circulating brine into and out of contact with the casing perforations and the cement tunnels to displace undeposited epoxy resin; and removing the packer.

Claim 10

A method for protecting a well completion having a cemented and perforated casing string from CO 2 degradation in which casing perforations and cement tunnels are coated after well completion by the method comprising: displacing debris from the casing perforations and the cement tunnels by flowing a well compatible aqueous liquid into and out of contact with the casing perforations and cement tunnels; suspending a retrievable packer with a tail pipe run on a tubing above the highest perforation in the casing; filling the casing perforations and the cement tunnels with an oleogenous liquid solution which includes an epoxy resin based on a glycidylether of bisphenol-A, a polyamine and phenol in an organic solvent and which is capable of subsequently forming and depositing a cured epoxy resin at the reservoir temperature, by chasing a volume of the oleogenous liquid solution, which is not significantly more than enough to fill the casing perforations and cement tunnels, with brine; maintaining the oleogenous liquid solution at least substantially stationary until a deposition of at least substantially cured epoxy resin has occurred substantially selectively within the casing perforations and the cement tunnels; releasing the packer and circulating brine into and out of contact with the casing perforations and the cement tunnels to displace undeposited epoxy resin; and removing the packer.