In a BP well on the south coast of England, pressure and fluid from the injection tubing were in communication with the annulus because of a leak path formed by corrosion of the tubing. This communication limited the maximum allowable injection pressure, which impaired the flexibility of the operator to manage the recovery program and thus reduced the recovery of hydrocarbons from the reservoir. Remedial treatment possibilities had to be compliant with considerations for the future abandonment plans for the field in that any treatment should not substantially impede or detract from efficient abandonment operations. A recompletion was not considered cost effective, and a mechanical straddle of the correct length was not viable. An annular barrier was chosen as the cost effective option when considering well life. Previously, the material predominately used to form the annular plug in similar situations was oilfield cement placed onto the production packer in the annulus. The alternative, novel rigid setting material, was chosen because of its differing suitable properties, which are (1) a high level of resistance to contamination, (2) expansion, (3) ease of milling, and (4) 100% acid solubility. These properties helped ensure that a uniform plug was achieved though the material was diluted by annular fluid between the production packer and the punched circulation holes in the tubing, and that a good seal was created so that the annular plug was not bypassed. Further, excess material can be easily removed from the tubing to bring the well on line with minimal delay and future abandonment operations are not onerous. In late 2006, the slurry was placed using a coiled tubing (CT) packer arrangement, with displaced fluid returned to surface for environmentally safe disposal. The ease of placement and reliable set of the material, with strength comparable to normal oilfield cement, can provide an effective alternative to commonly used annular sealing materials.

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