Curing Packer Leak Riglessly Using Bismuth: Results of the Field Pilot

Abstract

Abstract The concept of the well double barrier envelope is a common industry practice and main philosophy of well integrity discipline. This is well-described in some of the international standards: API RP90 (1 & 2), Norsok D10, ISO 16530 (1 & 2). This double barrier policy applies to wells with positive pressure at surface capable to flow naturally. Primary barrier envelope consists of well equipment which is continuously under pressure and in direct contact with hydrocarbon. In case primary barrier element fails, secondary barrier envelope will be the one exposed to well media and holding the pressure. This content of this paper is related to such kind of wells that can flow naturally and should comply to the double barrier policy. Any failure in the primary barrier envelope (means - completion) normally is addressed during workover by simply re-completing the well with new completion (after retrieval of the old one). This can be done almost unlimited number of times, as long as there is a place to set the packer. Failure in the secondary barrier envelope (means - casing) can be repaired as well, but not that easy and very limited amount of time. In some cases, especially for onshore wells it might be economically more reasonable to drill the new well rather than to deal with complicated workover. Depending on the Company policy, casing integrity can be restored in sections using casing patches or the entire length can renewed by running and cementing casing of smaller diameter. Obviously, in both cases it impacts the size of the completion, further well objectives and cannot be done multiple times.