Most if not all of the OPEC countries goosed up [sorry hardly a technical term ... but descriptive] their reserves circa 1990. This was done because production quotas were set based on reported reserves. More “reserves” = bigger quotas. A lot of production has occurred since. With no truly major finds since 1969 Saudi Arabia continues to report the same reserves. Ghawar [the granddaddy of all oil fields] is about half of Saudi production and a large portion of reported reserves when the western oil companies managed ARAMCO. With the exception of a of little [Khuff — spelling] natural gas production, production in Ghawar comes from one zone the Arab D. That zone was well mapped, explored and had been in production for a long time before the Saudis took over ARAMCO. The western oil companies knew what was there and most of that isn’t there any more. The numbers don’t add up.
Kuwait is another example. A rather small patch of desert. Quite well explored. Two million barrels of oil per day for decades and the reported reserves are basically unchanged.
Reserve growth also occurs as secondary and tertiary production techniques improve. No doubt about it. We will extract additional amounts from existing and sometimes previously abandoned oil fields. The problem once again is the rate of extraction. These fields will almost never be what they once were. We will however manage the decline by doing intelligent and aggressive things to extract more oil from existing fields. Having written that, the decline curves are nasty in the remote and offshore locations. I can make money with an existing two or three barrel a day onshore well in TX or OK if I don’t have to handle a lot of water. I have no direct knowledge of offshore costs but it is obvious that the operating costs are staggering. When well managed offshore fields go down, they often go down hard and with apparent finality. The North Sea is a classic example.
The other reserve growth category is even more slippery. Resources like the Alberta or Orinoco [spelling] tar sands / ultra heavy oils become economic at some price. At some price the US oil shales may become truly economic. When that point is reach a very large bump in reported reserves occurs. However, the means to produce those reserves don’t magically appear. By comparison, conventional oil production is easy. These require massive investment, that go way beyond a few thousand feet of 8 inch hole, casing, tubing, separators, pumps, tanks, etc.In addition, resource constraints mean that although the Alberta tar sands reserves are almost unimaginably large, extraction rates probably will never exceed two or three million barrels of oil a day. A lot of oil for sure, but the yearly decline in existing wells may higher than that hoped for five million per day number.
To keep the age of [at least relatively] cheap oil going, we are going to need something like the Brazil find or better every few months, not every seven year years. Hope that answered your question.
Thank you for your most informative explanations. Another question if you don’t mind: have all the world’s continents truly been well explored for potential oil & gas deposits? if ocean deposits are being found 23,000 - 35,000 below the surface of the sea might there not be a lot of land deposits/oil and gas fields at similar depths below solid ground? Have all the promising places on planet earth already been tested to such depths, or is there a way to know in geological terms that there are no more major finds to be had on land?
My original main point was that nothing will replace petroleum as the primary fuel of civilization until it's economically spent though. When that will be is up in the air even by your very well informed calculations IMO. I simply see no alternative edging petroleum out until it's effectively gone.