text: does oil replace its self as fast as it is taken?is it hollow space?   if your question is about how fast oil will come out of the ground, it varies. there are a very few oil reservoirs in the world where the oil is actually in hollow space, previously caverns, and these can be pumped out as fast as the pumps can go. most oil comes out of the ground quite slowly, sometimes a well may only pump a few barrels a day. the most prolific wells can produce several thousand barrels a day. however, to get the most oil from the well, the daily production is often limited because allowing it to come out quickly will damage the reservoir and often result in only producing water from the well after a short period.   if your question is about how oil is created and how long it takes, the answer is millions of years. the real answer is related to how long it takes for the organic material in rock to reach a certain pressure and temperature by burial under other rock. an example is the lower miocene age rock near south padre island. the oil generation took place between 135 degrees celsius and 175 degrees celsius at depths between 3,600 meters and 4,600 meters, while natural gas was generated between 155 degrees to over 200 degrees celsius and at depths of burial ranging from 4,000 meters to 5,000 meters and greater. this burial process is caused by rivers like the mississippi river depositing sediment on river deltas. this is what takes millions of years.