text: in oil fields, why do the pipes have a raised 'upside down u' every so often? driving through bakersfield, california, we notice white pipes in the oilfields that we presume are transporting the oil.   every so often, the pipe rises off the ground in an upside down u shape and then continues. it seems that would make it hard for the oil to flow through, and we wonder what it's purpose is. the gas that also comes up in the pipes is lighter than the oil so it rises as far as it can and then gets trapped in the "u" in order to avoid explosions.