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。
2
Steranes and terpanes exist in saturated hydrocarbon component of oil and source rock, and they are usually identified by gas chromatogram-mass spectrum.
甾萜类化合物存在于原油和生油岩的饱和烃组分中，通常用色谱-质谱法鉴定。
3
The gas cap pools, mainly distributed in Paleogene, are formed by spillover of undissolved gas in high saturatedoil pools.