Complex sentence: Soon after its establishment, NOC signed a "PSA" with Occidental Petroleum, a refining deal with Sincat (Italy) and a joint drilling company was formed with Saipem (an Eni subsidiary) in early 1972.
Split into simpler sentences: Soon after its establishment, NOC signed a "PSA" with Occidental Petroleum. A joint drilling company was formed with Saipem, a subsidiary of ENI, in early 1972.