Pyrolysis Simulation Experiment and Diagenesis Evolution Pattern of Shale

Key words: 
• shale /
• simulation experiment /
• organic matter evolution /
• reservoir space /
• diagenesis evolution pattern

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.