• Kontis, Paraskevas
• Sangesland, Sigbjørn
• Manataki, Andriani

Abstract

<jats:title>Abstract</jats:title><jats:p>Well-plugging and abandonment (P&amp;A) of oil and gas wells involve the placement of barrier plugs at critical intervals in order to prevent leak paths between the reservoir and the surface. As per the Oil and Gas UK Well decommissioning Guidelines a barrier material, among all the prerequisites, should also provide an interface seal or bond, preventing flow around the barrier plug at the interfaces with adjacent casing steel or formation rock. So far, the most well-known barrier material is cement. It is well-qualified, but since it has also some limitations, other materials, such as bismuth-based alloys, have been investigated as an alternative to cement. This study focuses on the use of the eutectic BiSn alloy for well plugging, with 58% bismuth (Bi) and 42% tin (Sn). Like all bismuth-based alloys, this alloy expands on solidification, which is considered an important property for improving its sealing capability in a well. In addition, the microstructure resulting from the interactions between the BiSn alloy, cement, and steel casing, will affect the sealing performance. For this purpose, lab tests have been carried out using a small-scale test set-up. By scanning electron microscopy, various microstructures, in the BiSn alloy were observed and correlated with the interaction of the alloy with the steel casing and the presence of cement.</jats:p>

Topics

• impedance spectroscopy
• microstructure
• surface
• scanning electron microscopy
• steel
• cement
• tin
• solidification
• Bismuth