When oil wells are drilled, they are lined with metal casings that support the surrounding geology and prevent gas, oil, and water from mixing in the well.
(oil wells; are drilled; ) (they; are lined; with metal casings; T:When oil wells are drilled) (metal casings; support; the surrounding geology) (metal casings; prevent; gas, oil, and water; from mixing in the well)
oil wells they metal casings metal casings
are drilled are lined support prevent
with metal casings T:When oil wells are drilled
the surrounding geology
gas, oil, and water from mixing in the well