Why do we have "stranded natural gas" if NGL is relatively easy to produce?

easy to produce (relatively) but at a cost (compression) and not necessarily easy to transport (facilities not in place to load or unload). natural gas is not easy to transport either. this is the reason for the price differential between the rockies (us) and gulf coast

If you check oil & gas company press releases you might find that some natural gas wells also produce a number of barrels of condensate per day, these natural gas wells were in gasfields (not oilfields). This natural gas was called non-associated gas. Associated gas was in solution with oil in oilfields and seperated out by GOSP's during the production process. Gas caps are the top portions of oil fields below the cap rock that contain natural gas. They also contained condensates (lighter petroleum molecules). Natural gas liquids or NGL's were stripped out of natural gas at surface facilities, these included butane and ethane. After the oil from an oilfield was pumped out, the gas caps were tapped for natural gas, condensates, and NGL's.

EIA definition of NGL's:

Natural gas liquids (NGL): Those hydrocarbons in natural gas that are separated from the gas as liquids through the process of absorption, condensation, adsorption, or other methods in gas processing or cycling plants. Generally such liquids consist of propane and heavier hydrocarbons and are commonly referred to as lease condensate, natural gasoline, and liquefied petroleum gases. Natural gas liquids include natural gas plant liquids (primarily ethane, propane, butane, and isobutane; see Natural Gas Plant Liquids) and lease condensate (primarily pentanes produced from natural gas at lease separators and field facilities; see Lease Condensate).

http://www.eia.doe.gov/glossary/glossary_n.htm

You appear to be making the same error that PartyGuy made - NGLs are not LNG. NGLs are liquid anyway. LNG is gas that has to be compressed, cooled, and liquified in order to be transported in special transports, the warmed, decompressed, and returned to naturally gaseous state in order to be used. We strand natural gas because it is costly to convert to LNG. We don't strand NGLs because they are already liquid and will come out of the well just like oil (and if you are not careful even more easily than the oil). As Bob Ebersole notes, these are very light hydrocarbons but in liquid form already. There is no work to do to capture them and transport them aside from what is already done to capture and transport the oil. Don't get confused thinking NGLs are LNG. They are not the same thing at all. What Simmons and others are saying is that as old wells go down, we are getting the benefit of the NGLs in place coming out. That has nothing to do with saving any natural gas (in gaseous form). Whether the natural gas itself gets saved is dependent on other factors. In many places in the world, even at today's prices, natural gas still gets flared off. Check Nigeria for some stunning and ugly examples.

"The greatest shortcoming of the human race is our inability to understand the exponential function." -- Dr. Albert Bartlett
Into the Grey Zone