Development of Organic Matter Porosity During Thermal Maturation: Study on the Example of the Bazhenov Formation Source Rocks

Abstract

Summary The porosity of shales consists of mineral matrix voids and pores in organic matter. Since organic matter occupies up to 50% of source rock volume and most of the pores are connected, this type of porosity may considerably contribute to saturation of rocks by hydrocarbons. The study is devoted to the investigation of organic matter (kerogen) porosity development during thermal maturation of source rocks using SEM. On the example of the Bazhenov Formation source rocks, we have demonstrated the presence of nano- and micropores in solid organic matter at the beginning of the oil window and a developed porous structure at the end of the oil window with organic matter porosity of more than 50% of kerogen volume. The obtained results expand existing knowledge on void space volume of the Bazhenov formation and show that organic matter porosity of mature kerogen may several times exceed intergranular porosity of rock.