They are looking for something better than water injection. Since the super light crudes were pumped out first, and then the light crudes, we're turning to the med, heavy & sour crudes. In Saudi Arabia, @ their largest oil field, @ the north end, the sweeter crude (API 35-40) was found in the more porous rock, most of that is gone. The API 31-34 med crude is found in less porous rock. So its slower to flow.scareduck wrote: Some of the secondary recovery approaches they had been looking into (high-pressure CO2 injection, in particular)
The 164 mile Gharwar oil field, north is @ top. Purple, blue and grean are water, the oil is red and yellow, natural gas white.
Water injection has flushed out a lot of oil, but tends to leave the injection site and follow the path of least resistance. By putting the water at the bottom of the crude formation, the intent is to force all the oil to oil rigs waiting to pump it out. Things like cracks in the rock can screw your oil flow up. Areas of varying rock porousity too. CO2 couldt be better than water