Complex sentence: Coryton Refinery is an oil refinery in Essex, England, on the estuary of the River Thames some from the centre of London, between Shell Haven Creek and Hole Haven Creek, which separates Canvey Island from the mainland.
Split into simpler sentences: Coryton Refinery is an oil refinery in Essex, England, situated on the estuary of the River Thames some from the centre of London. The refinery is located between Shell Haven Creek and Hole Haven Creek, which separates Canvey Island from the mainland.