This gas is hydrogen sulfide, risesup and mixes with oxygen in the underground water that sits in the cracks and fissures in the limestone.
这种气体是硫化氢,上升后与石灰岩裂缝中地下水的氧气混合。
2
When the well reaches a pool, oil usually risesup the well because of its density difference with water beneath it or because of the pressure of expanding gas trapped above it.