They drilled through several layers of rock to reach the oil.

他们钻透了几层岩石寻找石油。

《牛津词典》

Below the water table and rock is oil.

地下水和岩石下面是石油。

youdao

Both oil and gas are less dense than water, so they generally tend to rise upward through water-saturated rock and sediment.

石油和天然气的密度都比水小，所以二者通常会浮在被水浸泡的岩石和沉积物的表层。

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Australian rock heavyweight Midnight Oil has been reformed for the occasion.

VOA: standard.2009.03.14

Oil shale is sedimentary rock with oil in it that has historically been considered too expensive to process.

CNN: GOP lawmakers want special session on energy crisis

Bissell found out that some rock oil was a by-product obtained by drilling for salt.

FORBES: Magazine Article

In 1853 one George Bissell happened to notice a bottle of rock oil in a Dartmouth professor's office.

FORBES: Magazine Article