Repair corrosion of an offshore pre-salt producer, and/or convert it to an injector for CO2 EOR, and maximize recovery of reserves in deepwater wells.
To maximize recovery from pre-salt formations, secondary and tertiary EOR are often planned. Well lives greater than 10 years are usually necessary for offshore operations. Corrosion may develop in production casing over the life of the well, both from sour gas (H2S) and CO2 that are sometimes present in pre-salt reservoirs, and from fluid/particle erosion.
For the EOR phase, to maximize slot usage, it is desirable to convert an existing production well to an injection well, which may often involve sealing off old perforations and re-perforating in a lower interval. Produced CO2 can be used with water for WAG (water-alternating-gas) EOR programs, which can add to existing corrosion. A reliable and efficient means of sealing perforations and repairing corrosion is required.
If production declines to unsustainable levels, a reliable and efficient repair or production enhancement strategy is needed to minimize non-productive time and enable the well to be restored with the required well integrity and production capacity.
To repair production casing and/or to seal off old perforations, Enventure’s expandable cased-hole-liner (CHL) can be used. In most cases standard grade EX-80 CHL can give sufficient performance and lifetime in CO2 environments, but if better corrosion resistance is desired (for instance for sour gas), more corrosion-resistant alloys are available, such as 13Cr. Expandable CHL’s are available for production casing sizes of 5-1/2, 7, 7-5/8, 7-3/4, 9-3/8, 9-5/8-in., and larger if required.
Production enhancement strategies such as sidetracking can be done utilizing expandable open-hole liner (OHL) of the same sizes.
The SET® Chart provides a table of all the standard sizes available or you can use the SET® Designer to configure a system based upon your parameters.
Repairing corroded casing with expandable CHL’s can restore a well's casing integrity and extend its producing life to maximize recovery of its hydrocarbon assets. Covering old perforations with expandable CHL’s provides a reliable and consistent method of zonal isolation to enable EOR to produce economically significant amounts of residual oil and gas from a reservoir, while allowing for future workovers by minimizing hole ID loss. Sidetracking with OHL’s provides access to additional reserves.
