How much of the petroleum ever formed has made it into reservoir rocks? I am aware that it's a bit general a question, and petroleum geology (or petrology ;-)) has never been a field of interest to me. A superficial search using related keywords brings up only economic figures about percentages here and there.
From a geoscience point-of-view is there any chance to give an estimate, however rough it may be, of how much was ever produced in the biospehere (and abiogenic if that plays a role and can be set in number), and how much of that made it into reservoirs ?
I am very well aware that there is a lot of uncertainty, concerning formation processes, mobility in the crust, amount of current storage, past conditions favourable for the formation, etc, but maybe petroleum geology has once thought about it, and knows a rough number.
In its 1995 assessment of total world oil supplies, the U.S. Geological Survey (USGS) estimated that about 3 trillion barrels of recoverable oil originally existed on Earth and that about 710 billion barrels of that amount had been consumed by 1995.
Britannica

There may be much larger quantities that are not &quot;recoverable&quot;, depending on technology and economics.
Also, for example, 914 persistent natural seeps across the Gulf of Mexico collectively discharged about 500,000 barrels of oil per year. If that has been seeping for millions of years, that is a lot of oil that is not in reservoirs.