地表土壤中物理吸附轻烃的石油地质意义

Petroleum geological significance of physical absorption of hydrocarbon in surface soft

油气藏中的轻烃在和环境进行物质和能量的交换过程中,各赋存状态轻烃在沉积岩表面的作用下构成了一个动态的物理化学平衡。油气藏上方地表土壤中的物理吸附轻烃主要来源于油气藏,其组成和含量上的特征可反映油气藏的性质和特征。根据环境中物理吸附轻烃的含量与组分特征,可追踪出轻烃供给源(即油气藏),并可进一步预测与推断出油气藏的性质和特征。物理吸附轻烃技术是让样品在真空状态下比较完全地释放出所吸附的物理吸附轻烃,用气相色谱仪定性和定量分析其中的轻烃组分,然后根据轻烃的浓度变化来推断油气藏的性质和特征。物理吸附轻烃技术在岩性变化很大的四川盆地新场气田实验剖面上、在地质及地表条件复杂的鄂尔多斯盆地镇原-泾川黄土塬实验区及塔里木盆地柴窝堡戈壁实验区都有很好的油气指示意义。该技术取得了很好的应用效果且有着广泛的应用前景。

During a mass and energy exchange between the light hydrocarbon in reservoirs and its environment, a dynamic equilibrium is formed by the light hydrocarbons of all states under the action of sediment surface. The light hydrocarbon physically absorbed by surface soil mainly comes from the reservoirs below and their composition and content can reflect the nature and features of the associated reservoirs. By tracing the composition and content of absorbed light hydrocarbons, the hydrocarbon source （ i. e. reservoir） can be located and its quality and characteristics can be predicted. The technology of physical absorption of light hydrocarbon is to completely release the physically absorbed light hydrocarbons from soil samples in a vacuum state and qualitative and quantificational analyse the composition of released hydrocarbon with a gas-chromatogram, so as to predict the quality and characteristics of the reservoir through an observation of the concentration change. The application of the technology in the pilots in Xinchang gas field of Sichuan basin, in Zhenyuan-Jinchuan loess tableland of Ordos basin, and in Chaiwopu Gobi of Tarim basin both with complex surface and geologic conditions gains positive resuits and implies a bright future for its further application and development.