Reflekt has been requested by the Petroleum Safety Authority (PSA) to review current knowledge on Bismuth alloy applications for permanent plug and abandonment (PP&A operations).
The purpose of this report is knowledge acquisition.
The main intention is to give a status on where the industry is and where the industry is going with respect to development, testing and use of Bismuth alloy as a well barrier material for offshore wells in Norway.
Reflekt has not been asked to, nor intends to provide any opinion on the different technologies and the suitability of Bismuth alloy as a well barrier material. The descriptions of the suppliers’ technologies in this report should not be interpreted as any view on the technology or the quality of the ongoing qualification processes.
The PSA’s regulations on securing of wells (Activity Regulations 88) include assurance that there will be no leakage of hydrocarbon to the environment once the well has been abandoned. The conventional way of plugging wells is using Portland cement, and the industry has long experience with cement for drilling & well applications, including PP&A.
One of the new technologies currently being pursued is the use of Bismuth alloys as a well barrier material. Bismuth alloy can be deployed using wireline/electric line and is therefore feasible without use of a drilling rig.
At this time, Bismuth alloy has been qualified and used by one Operator on the NCS as a well barrier material in wells with low differential pressure and low ambient temperature.
The following companies have provided knowledge and input to this report; Aker BP, Total Energies, BiSn, Interwell, ISOL8 and Wellstrøm. SWIPA (Subsurface Well Integrity and Plug & Abandonment, a consortium of SINTEF, NORCE, NTNU. IFE and UiS, has also contributed.