The challenge was with wells where the casing had lost its barrier/integrity because of casing leakage. There the result was that production wells were closed in. These problems are often caused by cementing failure when the well was drilled and cemented, lost zone, experienced corrosive formation fluid from the formation, treads leakage or other reasons for this integrity failure. There have been tried out serial methods for how this casing leakage can be repaired safely and in a cost-effective manner.
Casing damage/leakage with low or non-injectivity have been squeezed and repaired with Thermal activated resin. Thermal activated resin is a nonreactive polymer with qualities that are resistant to all formation corrosives/hazard fluids. Thermal activated resin will reinstall a good well barrier and integrity to protect casing from future corrosion. Thermal activated resin has been used in serial wells in Saudi Arabia in both onshore and offshore fields. In a small volume, with a controlled setting and short operation time, a high success rate has been achieved.
The solution to these challenges was developed by designing thermal activated resin casing repair liquid plug with a density equal from 64 pcf to 152 pcf. The setting time can also be adjusted accurately. This new treatment slurry was able to be bullheaded and displaced with polymer mud/brine at 64 pcf to 152 pcf. The slurry was easily able to be pumped through the drill pipe. This novel product possesses low elastic modulus and high flexibility in density, viscosity and fast setting time according to requirements. The well barrier elements made of this product have no risk of shrinking, cracking, gas channeling or deterioration upon exposure to harsh reservoir environments.
This paper presents a case history and field application of this novel polymer based casing repair material for successful treatment of full losses or when there is no/low injectivity in formations in most of the critical oil and gas fields in Saudi Arabia. Also, the paper includes a discussion of the methodology, material properties and applications.