Nexen, formerly known as Canadian Occidental Petroleum Ltd., is an international oil and gas company with headquarters in Calgary, Alberta. Along with petroleum resources, the company has a chemicals division. The company has offices in Canada, the US, South America, Africa, Asia and the Middle East. It has three core businesses: Conventional Oil and Gas, Synthetic Crude Oil and Chemicals. In its Oil and Gas segment, the Company explores for, develops and produces crude oil, natural gas and rela...