This is not my area of expertise.
Don’t producers pump hot water or steam into old wells to increase production?
Also, doesn’t oil seep into these denuded reservoirs, from below, over time, thus replenishing the reservoir?
“Don’t producers pump hot water or steam into old wells to increase production?”
At times, yes if the conditions are right for secondary or tertiary recovery, which loosens up oil in formation to move toward a producing well. Typically, one does not pump steam or water into a producing well, but into a nearby injection well to move the oil toward the producer. Most stripper wells have no injection nearby, but instead produce by a slow ‘bleeding’ over time.
“Also, doesn’t oil seep into these denuded reservoirs, from below, over time, thus replenishing the reservoir?
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That is one theory that abounds, i.e. - a perpetual recharging. This could take millennia, which may not be long in geologic time, but is very long in human time so as to make it non-existent.
A reservoir is never really ‘denuded’, which I take you to mean the rock is stripped of oil. Most reservoirs average between 30% to 60% recovery of the oil originally in place over its economic life, with some rarities achieving as high as +90% and a lot in single digits. The type of reservoirs developed today(unconventionals) are thought to be able to recover on the low end, 5% up to maybe 35%. The recovery is weak as the rock is so low in permeability.