| Abstrakt: |
Pore structure is a significant factor affecting reserves and recovery ratio of tight oil reservoirs. We should use experimental methods, such as scanning electron microscope, to study on occurrence characteristics of Ordos’s tight oil by high pressure mercury intrusion and CO2 and N2 gas, targeting shale samples from the Late Triassic seven period and Late Silurian Yanchang Formation. We researched on porosity, pore types, property and pore size distribution, and we probed into the key factor affecting pore structure of shale. The results showed that: 1Shale porosity in late Triassic in Ordos is during 1.30- 13.37%, with an average of 4.56%; 2Micropore type of shale are intergranular pores, organic pores, granular inner pores and so on; 3Organic pores are common, which are able to offer space to store dense oil; Micropores (< 2nm) and mesopores (2-50nm) were used in Late Triassic tight oil in Ordos area). Total surface area accounted specific surface area for 94.3%, and volume of two pores accounted for 59.1% in total pore volume. The pore size is mainly distributed in three parts: 0.4-0.7 nm, 3-10 nm and > 50 nm. Porosity and aperture of extension layer are diffirent from the seventh floor of Changsha. Yanchang Formation’s average shale porosity is 6.4%, and its average aperture is 4.71nm. The Triassic tight oil reservoir’s average aperture of is 5.3%, and its average aperture is 4.23nm, which is subject to organic matter maturity and mineral content. As the number of porosity and pore volume of shale rose, maturity increased. With the increase of clay mineral content, porosity and shale pore volume tend to decrease. [ABSTRACT FROM AUTHOR] |
