Abstract
<jats:title>Abstract</jats:title> <jats:p>A benchmark testing methodology is developed to evaluate the performance of annular barrier remediation technologies, such as Perf, Wash, and Cement (PWC) systems. The approach establishes a consistent basis for comparing different PWC tool types and operational processes under realistic well conditions. The test design, relevance to field operations, and successful implementation in a full-scale well environment representative of plugging and abandonment scenarios is described. The methodology was developed and validated through a sequence of experimental and field-representative stages. Annular samples of settled barite collected intact from two North Sea wells through casing-in-casing retrieval during well abandonment operations were studied. Laboratory analysis characterized their bulk density, acoustic impedance, surface hardness, erodibility, and mechanical response through push-out testing. Based on these results, an equivalent laboratory material was formulated, consisting primarily of barite with a minor cement fraction to reproduce the physical and mechanical behavior of the downhole samples. This material was successfully mixed in a batch mixer, pumped into a 5in.×7in. annulus, and verified for adequate placement and hardening. Full-scale test fixtures were thereafter manufactured using a 9 ⅝in. casing welded inside a 14in. outer casing. The 9 ⅝in. casing was pre-perforated with a perforation entrance hole size and shot pattern that matched the perforating gun planned to be used based on a typical well candidate. The test fixtures were filled with the laboratory-developed barite-based material and deployed in a P&A test well, where the PWC operations were executed as planned. All fixtures were retrieved intact after testing, enabling direct comparison of the different PWC technologies. The results demonstrate that the developed test methodology provides a reliable, field-representative benchmark for evaluating annular remediation performance and comparing PWC system effectiveness.</jats:p>