新疆准噶尔盆地克-乌大逆掩断裂带烃类热成熟作用

本文应用定量方法研究了逆掩断裂带在逆掩发生后,断层上下盘岩石由热传导作用导致的热效应,并将这种逆掩热效应和洛-韦TTI方法结合起来,利用镜煤反射率等成熟度指标,进行该带生油岩热模拟和古地温的恢复;介绍了简单的一次逆掩和较复杂的多次逆掩热效应定量研究方法;通过对逆冲盘厚度不同的克-乌逆掩大断裂、扎伊尔逆掩断裂带对比研究,探讨了逆掩热效应的主要影响因素,最后对上下盘烃类热成熟作用过程进行了讨论。

MATURATION OF HYDROCARBONS IN KLAMAI-ULH OVERTHRUST BELT

This paper applies the mathematics model of the overthrust thermal effect described by Angevine, et al. ( 1983 ) to study the thermal history of the Permian source rocks in the Klamai-Ulh overthrust belt. Based on the thermal maturity indexes, such as the vitrinite reflectance of samples collected from different structure position, the paleotemperature is recovered and thermal maturity evolution of organic matters simulated. The thermal modeling demonstrates that the maturation of the source rock located at the lower part of overthrust stage increased owing to the affection of thermal conduct deriving from high geotemperature of the overthrust-sheet bottom, so the source rock of Permian reached the stage of oil-generation peak at the beginning of Jurassic. Howerer, the velocity of the source-rock maturation of the same age in the upper wall slowed up due to quickly cooling, and the maturity was almost not elevated in the post-overthrust stage. This mold of the overthrust thermal effect canbe applied to not only simple overthrust, but also multiple thrust. In this paper Zayier Overthrust Belt is studied as an example of multiple thrust. As its overthrust sheet is very thick and the overthrust thermal effect rather strong, the velocity ef thermal maturation becomes rather quick and source rocks come into overmaturation quickly.