油井 is read as ゆせい (yusei) and means oil well.
ゆせい
yusei
ゆせいかん
oil well pipe
あぶらげ
aburaage
ゆさい
oil painting
あぶらやし
oil palm (esp. the African oil palm, Elaeis guineensis)
あぶらしょうじ
shoji with an oil-treated screen (for increased water resistance)
ゆうてぃあお
youtiao
ゆだんたいてき
don't let your guard down
ゆでんくっさくしせつ
oil rig
てんじょう
ceiling
いちい
the street
い
well
つつい
round well