塔里木盆地海相油藏热稳定性的物理化学条件探讨

塔里木盆地在埋深超过8000米、油藏经历200℃以上高温仍然发现液态烃类流体稳定存在，目前勘探工作正在面向深层-超深层拓展。塔里木盆地原油热稳定性与四川盆地、鄂尔多斯盆地海相油藏比较起来具有特殊性，除开宏观地质构造演化、盆地热史差异等因素外，油藏储层的矿物组成、地层水的发育特征、烃/水/岩相互作用等微观物理化学过程也是重要的影响因素。 本项目结合宏观地质背景演化，从微观过程入手探讨塔里木盆地海相油藏热稳定性的物理化学特征，主要通过模拟实验研究原油组分与不同矿物组分之间的烃/水/岩相互作用特征，重点探讨其微观化学过程中自由基反应和离子反应机理的贡献程度；研究含硫化合物、特别是单质硫对原油稳定性的影响及其机制；利用塔里木盆地实际原油、储层和地层水样品模拟研究烃类流体的热稳定性。预期研究结果可以明晰塔里木盆地海相原油热稳定性的微观物理化学特征及其机制、有助于深化塔里木盆地深层油藏的勘探研究工作。

Some hydrocarbon fluids were found still thermally stable occurred in the Tarim Basin, NW China, even over the burial depth of 8000m or the oil reservoirs experienced high temperature more than 200℃. Therefore recently more exploration studies have been targeted to the deeper strata in order to find more marine crude oils in the Tarim Basin. The thermal stability of crude oil reservoirs in the Tarim Basin may be somewhat special compared to those from Sichuan or Ordos Basins. Besides the tectonic evolution background, the mineral constituents of the reservoirs, the formation water occurrence, and the physiochemical reactions between hydrocarbon, water and rocks are the most important constrained factors to the thermally stable preservation of the crude oils. This project is aimed to probe the physiochemical features of the thermally stable crude oil reservoirs in the Tarim Basin, mainly through the simulation experiments to study the physiochemical reaction mechanisms between the hydrocarbon, water and rocks. Especially to evaluate the relative importance of the radical reaction and the carbon cation mechanisms during the chemical reactions of hydrocarbon/water/rocks, and thus the constrained factors of the thermally stable occurrence of the crude oils in the Tarim Basin will be probed by using the geological reservoir rocks, the formation water and the crude oils. The action of the elemental sulphur to the hydrocarbon fluids will be particularly investigated concerning its role to the thermal stability of the crude oils and the formation of sulphur-containing compounds in the oils from the Tazhong Uplift. Accomplishment of this project will be helpful to the further exploration studies targeted to the marine crude oil reservoirs deposited in the deeper strata in the Tarim Basin, NW China.