I'd also suggest that rate of production is a serious element. How fast and at what volume are they able to process the sludge back into a usable state? On the above linked website, their faq identifies at least three different processes and handling methods determined by the state of the sludge. So this isn't a simple or even expedient process and will be limited by the specific technical and infrastructure demands of the method. If they can start producing a hundred thousand barrels a day from sludge, there remains a significant shortfall to in the refining supply chain which can't operate efficiently or even at all at reduced thresholds.