Positive and negative building
an oil rig

Possible positive consequence:
It will create works and it will develop the area where oil will be brought and treated

Another possible positive consequence it will bring oil to develop industry and transportation to the country which makes the oil rigs.

Negative consequence:
If one country build an oil rig for example China and other country for example Vietnam doesn't agree there maybe fighting or demonstrations and people can be killed.

Another negative consequence is oil spill in case of accident and the pollution of the sea