The primary problems have nothing to do with geology or the study of petroleum. You see, oil is so much lighter than water, that there is about a 350 PSI difference between oil and sea water at that depth. It gets worse. I forget how far the well is tapped under the sea bed, but the pressure of the ocean floor over the oil, and extra depth, makes the pressure rather extreme. If I recall correctly, the oil pocket is around 18000 ft. This 350 PSI difference now becomes about 1200 PSI for just the difference between oil and water. However, only the fort 5000 or so feet are sea water. The remaining almost 13000 feet is sea floor, at a greater density than sea water. We are now talking of at least 2000 PSI differential pressure. This is how I understand the sciences. I have been told the pressure is actually about 3000 PSI.
Now tell me. Just how is normal petroleum sciences going to deal with deep underwater problems?