Rig can have more than one meaning.
In the first sentence it is referring to 'oil rigs', which are the facilities used to drill, extract and process crude oil.
The verb 'to rig' means to 'to fix' or 'to tamper' i.e. they are trying to manipulate the situation so that the oil prices are favourable for them.
Yes shale beds refers to the shale formations in the Earth, from which they will get the oil.