what kind of visa do I need for a two(2) weeks professional Training?

Dear Sir/Madam,

Am an employee of an oil and gas company based in port Harcourt and wish to attend a two(2) weeks professional training in Shangai China. what type do I need to apply for.

The training organization has requested me to contact the china embassy in Nigeria with the view knowing type to be stated on the invitation letter.

Also, what are the requirements