This is the third post on the life of a large oilfield, after first looking at a very idealized outline of how a major field might be developed, in the second post I gave some of the events that happened at Abqaiq, which is one of the great oilfields of Saudi Arabia, and which approximated my model. What I would like to try now is to explain some of the reasons that the reality is quite a bit different from the ideal, and some of the geological factors that make the considerable difference between the two.

To begin, Abqaiq, like most giant fields, has been around for a long time, and when it was first developed, by a relatively small group during the Second World War, there were many other things going on that limited development so that it took 4 years to go from drilling the first well to the fifth. Technology was not nearly as advanced as it is now, and the wells were spaced considerably further apart than the spacing I placed mine at in the model. Further while I had estimated the OIP as being some 62 billion barrels, based on porosity, in reality the number was half that. I am grateful that both westexas and plucky underdog had the reasons for this.