A Case Study on the Importance of Well Surveillance When Evaluating Alternative Barrier Technologies

Abstract

Abstract Recent years have seen accelerated development of alternative barrier technologies to address the limitations of cement well integrity remediation. These technologies have the potential restore well barriers with increased effectiveness and reduced cost. However, industry acceptance of alternative barrier technologies has been slow due to the challenges of demonstrating their effectiveness in field application. Using well surveillance to evaluate the well integrity issue and verify barrier performance is often overlooked leading to poor or inconclusive outcomes. The presented case study is a trial deployment of a chemical isolation solution supported by FiberLine Intervention (FLI) which was deployed to verify the barrier placement and performance. The unique feature of FLI is that it deploys bare optical fibres into the wellbore without requiring any conventional conveyancing methods, such as slickline or wireline. This makes it portable and compact, but with rapid deployment and real time survey capability it permits operations to be performed very quickly. This was critical to the operation due to time sensitivities around the pumping operation. When the chemical isolation trial was not successful post pumping, the distributed sensing survey with FLI was able to diagnose that the chemical had not reached the intended target formation. It also identified that this was due to a loss of well integrity in the casing higher up the well. This provided the operator with information on a previously unknown integrity issue, but crucially without this it would have been assumed the treatment simply had not worked which would ultimately delay acceptance of this technology.