How do we know that the mega-giant oil field in Saudi Arabia is depleting?
Do we need to know beyond the shadow of a doubt? Even small kids know that when you are in a pasture and you hear hooves, it’s time to run.
An article at the Oil Drum presents a movie on the drilling of Uthmaniyah.
Using a set of wells in a productive (but now rather depleted) slice of this part of the Saudi oil field of Ghawar, it is possible to deduce to drilling sequence of these wells using the identifiers assigned to the wells as they are drilled. Given a few known dates for well placement, a timeline for overall development can be constructed and displayed as an animation.
The Making of the Movie
Until the early 1990s, all wells (oil, water injectors, gas, etc.) in Saudi Arabia were assigned a numerical ID with the same sequence of numbers for a given field or area. The Ghawar areas are all numbered independently, such that the discovery well in Uthmaniyah is UTMN-1 and the tenth well in ‘Ain Dar is ANDR-10, etc. Under this assumption, a map showing both the locations and IDs of the various wells also gives the drilling sequence. Furthermore, if the drilling of a given well (by ID) can be independently attributed to a specific date, the drilling sequence can be anchored at that date. For example, the first well was placed in Uthmaniyah in around 1951 — thus providing the lower anchor for the sequence. Of course, this depends on the wells used being representative of the entire Uthmaniyah area. Fortunately, this appears to be true in this case. I will discuss below the sources of information and the assumptions made when assigning dates for the various wells.