I've discovered a search technique that, if you don't already know it, is helpful in searching this China-Cuba drilling issue.
Use "CUPET" in a Google news search or a Google web search. Then refine, or search within those results, for China.
Having done all that, it appears to me that Cuba contracted with the China company to, in 2005, drill/explore shallow water off the western province for heavy/high sulpher oil. When the rush began(2006) in the northern basin, China leased some equipment to those other companies.
I keep a watch at http://www.rigzone.com/news/
They track all of the offshore drilling rigs in world and report on related news. They even have average rental rates. More information is available for a subscription but much is available free.