[thackney]

However, if the gas found in a particular oil drilling site is too low of a concentration, say 550 but/ cu ft, it is unsuitable for blending because far too much expensive gas would be required to make the end product burnability acceptable.

For natural gas to have such a low BTU rate, it must have significant contamination with non-combustibles like CO2.

Even blended with higher BTU natural gas liquids, it is not going to be accepted as pipeline quality gas. The standards require more than just BTU rate.

Just like a gas with too high a BTU rate, that low quality gas will needed to be cleaned up at a gas processing plant.

For example:
http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_009b/0901b8038009bf53.pdf

[cartoonistx]

I was assuming the gas was scrubbed at one point (plant lab) in order to get an accurate BTU assessment.