NGLs value in the Marcellus Region

How is a royalty owner compansated for the high btu content gas versus dry gas?

I need a thorough explanation of how the NGLs go through the system.

What is the value of the NGLs at the well head in comparison to other points in the system?

If they are enhanced for increased market value, what does this mean? is this fractionation? what other process?

Are they sold and royaty based on the actual value of the products like ethylene, pentane, and others?

Is there a published value for these products similar to crude oil or natural gas?

What type of company are the products sold to?

Please Advise!