Abstract
Zonal isolation is pivotal for the well lifecycle and sustainability of well production. Zonal isolation has been achieved by designing and selecting a casing setting strategy, preparation of the well for the cementing process, selecting of cementing system, optimized cement placement and evaluating by wireline tools or by indirect indicators. Historically, we have relied on wireline cased hole logging to loop the process and give feedback on cement quality that is supposed to "mirror" zonal isolation. Lack of zonal isolation is normally addressed via revision on cementing process by changing the chemistry, placement technique or enhancement related to borehole preparation, improving the flow of cement across the zone of interest or way to evaluate the quality of cement.
Operator companies are constantly in search for the New Technologies, Best Practices and Approaches that will deliver adequate zonal isolation. All the above mentioned will improve Zonal isolation but there is a certain limit to the level of improvement (how much improved) and the period to get a substantial impact (how fast improved). Sometimes these improvements could be marginal and do not deliver the optimal ratio between efforts and expenditure spend and improvement.
Many operators demand significant improvements that could be delivered through changing the well design approach. Our analysis and lessons learned on the application of different well designs and their impact to zonal isolation are presented below.
