高温高压条件下铁岭灰岩晶包有机质的饱和烃演化特征

Evolution characteristics of the saturated hydrocarbonsin the crystal enclosed organic matter in Tieling limestone under high temperature and high pressure

对铁岭灰岩抽提除去沥青“Ａ”后的残渣进行高温高压模拟实验。模拟实验研究表明，晶包有机质的释放与温度和压力有关，高压有利于晶包有机质释放。晶包有机质和干酪根主要释放出低碳数烷烃，Ｐｒ／ｎＣ１７ 、Ｐｈ／ｎＣ１８ 在热演化过程中变化不大，Ｐｒ／Ｐｈ 则波动较大。７０％ 左右的晶包有机质在Ｒｏ 为２ ．２％ 前释放。干酪根热降解所生成的烃类没有进入到残留的晶包有机质中。高压下晶包有机质的热演化要比低压时慢。

The crystal enclosed organic matter in Tieling limestone chiefly releases lower carbon number alkanes under high temperature and high pressure. The simulating experiments indicate that about 70% of the crystal enclosed organic matter has been released when maturity(Ro) of the limestone is 2.2%, and that those hydrocarbons yielded by the kerogen do not mix into the residual crystal enclosed organic matter in the limestone. Generally, ratios of Pr/nC17 and Ph/nC18 change little, but that of Pr/Ph fluctuates irregularly during the experiments. Thermal evolution of the crystal enclosed organic matter is slower under high pressure than that under lower pressure. That is, the higher pressure deters the crystal enclosed organic matter from releasing, which shows that the crystal enclosed organic matter in carbonate rocks can yield liquid hydrocarbons (oil) and considerable gas hydrocarbons in the deep of basins when the maturity is above 1.8%.