East Texas Oil Field (1930) • • Largest “lower-48” field Unconformity Unconformity T T rap rap W W est est East East Sea Level Sea Level Reservoir Reservoir 1,000 1,000 2,000 2,000 Seal Seal 3,000 unconformity 3,000 unconformity 120°F Discovered in 1930, the East Texas oil field was located first from surface mapping.  It is a combined structural/stratigraphic trap with an erosional unconformity on one limb of folded strata. Kitchen Kitchen • • Largest “lower-48” field Largest “lower-48” field • • More than 5 billion barrels recoverable More than 5 billion barrels recoverable American Association of Petroleum Geologists, 1990