flare gas is easier, because you have already got it out of the ground and you are flaring it because there is no infrastructure of gas pipelines to transport it. Pipelines are expensive and requires complicated permitting and therefore politically challenged.
Two problems here, both solvable:
Collect the flare gas with a gas pipeline
Transport all that gas to a gas turbine
As you can see both are investment heavy before you even produce a single kilowatt of electricity. The economics of this at any kind of small project scale is negative. So unless you like to burn a lot of cash, there is no point of doing this.