Venezuelan/US joint venture oil company Petropiar experienced two separate incidents on 14 November.
In Caracas the floating roof of tank number four collapsed at its 180,000 barrel-per-day oil upgrader facility.
Four hours earlier two workers were burned in an accident at the coke unit.
Venezuela's four upgraders turn the Orinoco belt's tar-like crude into up to a total of 620,000bpd of exportable oil but they are frequently interrupted by accidents and planned stoppages.
Petropiar is a joint venture between Venezuela's PDVSA state oil company and Chevron.