摘要:
随着泥页岩油气勘探开发的不断推进,对泥页岩的成岩作用研究越来越受到重视。通过对三种不同干酪根类型的泥页岩样品的热模拟实验发现,随着有机质成熟度的增加,干酪根热解生烃产生的有机质孔及不稳定矿物溶蚀孔增加,是泥页岩储集空间增加的主要原因;泥页岩成岩作用类型主要有黏土矿物转化、不稳定矿物溶蚀作用和重结晶作用;结合镜质体反射率,建立了基于热模拟实验的泥页岩综合成岩演化模式。研究表明:不同类型的干酪根在生烃过程中演化特征不同,Ⅰ型干酪根以"解聚型"的途径生烃,以产生有机质边缘孔为主;Ⅲ型干酪根以"平行脱官能团型"的途径生烃,以产生有机质内部孔为主;Ⅱ型干酪根介于两者之间,既可以产生有机质内部孔,也可以产生有机质边缘孔。
Abstract:
With the extensive exploration and development for the shale hydrocarbon, researchers pay more and more attention to the research of the reservoir characteristics of the shale. This article conducts pyrolysis simulation experiment on shale samples containing three different types of kerogen. It reveals that as the increasing of maturity of organic matters, the organic pores are produced in pyrolysis hydrocarbon generation of kerogen and the dissolved pores are produced in the solution of unstable minerals increased. Both of the two kinds of pores are key to the enhancement in reservoir space of shale. The diagenesis types of shale mainly include clay mineral transformation, dissolution of unstable minerals and recrystallization. The article has described a comprehensive diagenesis evolution pattern based on pyrolysis simulation experiment combined with vitrinite reflectance. The current study shows that different kinds of kerogens have diferent evolution characters in the hydrocarbon generation. At the edge of kerogen type Ⅰ, pore is produced in "dissociative hydrocarbon generation"; whilst inside kerogen type Ⅲ, pore is produced in "paralleled removal of functional group hydrocarbon generation". The characters of kerogen type Ⅱ in hydrocarbon generation are between type Ⅰ and type Ⅲ, and it can produce organic pores both inside and at the edge of the kerogen.