Abstract
The paper will present and discuss the reliability of carbon steel tubings installed in dual-completion water injection wells through looking at historical data pertaining to identified leaks and workover frequencies. The durability of carbon steel tubing in this type of water injector will be contrasted with glass reinforced epoxy (GRE) lined and wrapped tubings. Corrosion in downhole tubing results in production/injection loss and the incurrence of additional operational costs through multiple rig interventions. This calls for exploring feasible and prudent solutions to extend downhole tubing life and minimize workover operations.
In field-A, water injection wells have different completions depending on the specific application and use. Well-X has a unique dual-completion design that enables combining water production and water injection in the same well. This was achieved through completing this well in two zones (a water producing zone and a water injecting zone). The water is supplied from one formation through the tubing casing annulus and then injected into the second formation through the tubing using a surface injection pump. The water producing formation is known to be corrosive, and several outside corrosion attacks have been observed in these dual-completion water injection wells. Well-X has been worked over two times in the first 8 years of its life cycle. This was due to external corrosion of tubing, especially below the casing perforations, where the fluids stood stagnant.
Realizing the need to reduce workover frequency on this well by extending the tubing life mandates looking into all alternative options. An innovative solution was applied using GRE lined and GRE wrapped carbon steel tubing all the way from packer to surface. As a result, the well continued to operate for an extended period of time with no integrity issues.
