Middle Eastern crude and condensate supply losses reached 782 million barrels by May 8 and could approach 1 billion barrels later this month, Kpler said Wednesday.
Regional crude and condensate outages have stabilized near 12.5 million barrels per day in recent weeks as producers adjusted operations to weaker export capacity and lower domestic demand.
Kpler said disruptions intensified during the past two weeks as the US blockade reduced Iran's export capacity and forced producers to scale back domestic operations.
Iran has shifted remaining ballast tankers in the Middle East Gulf into floating storage to limit further production shut-ins, though available storage capacity is rapidly declining, the report said.
Iranian onshore crude inventories continued to rise through May, reaching 66 mmbbls on May 7, up 6 mmbbls from late April, according to Kpler.
Kpler still expects a gradual reopening of the Strait of Hormuz by the end of May despite ongoing disruptions across Middle Eastern crude supply chains.
The report said Middle Eastern outages significantly shifted the global crude balance, after markets had previously expected large oil surpluses in March and April.
Global crude deficits averaged about 2 mmb/d in March and April as weaker refinery activity in Asia and softer fuel demand partly offset supply losses, Kpler said.
Global onshore crude inventories fell by 60 mmbbls since late March to around 3 billion barrels, implying average stock draws of roughly 2 mmb/d, according to the report.