Depends on the view the Tribunal takes as to the lack of support given by the State and local courts to international investors and assets they acquire in Kazakhstan, supposedly protected by the 1992 treaty.
Looking at earlier cases such as Stati, Cartatube 2 etc., one could quite reasonably formulate a claim including interest of up to $1bn. BSKO's fields such as Morskoe etc., were in production, and have continued so to the current reported level of 17k bbls/day plus. Remember also the local company was sold to Geo-Jade in 2014 at variously reported amounts of between $340-$400m, so it has a recent merited factual significant market valuation figure.
The Kazakhstan government has been trying also to hide offshore assets of the State from the risk of appropriation by successful litigations. That aside they will no doubt in addition try to appeal any judgement made by the Tribunal not in their favor. Jmo..
https://
www.prnewswire.com/news-releases/dutch-court-upholds-5-2-billion-asset-freeze-on-major-kazakhstan-oil-field-300845372.html