| PDF: | |
| Time: | 2020 |
| Journal: | Acta Petrolei Sinica |
| Volumn: | 41 |
| Issue: | 12 |
| Pages: | 809-820 |
| Type: | EI |
| Author: | Tang Huafeng,Dai Yanlin,Guo Tianchan,Liu Zhao,He Xianpei,Zhang Yichi |
Abstract: | The extrusive volcanic edifice had been revealed as the gas pool in Songliao Basin in recent years. The reservoirs feature has distinguished difference to the explosive and effusive volcanic edifices. This manuscript takes the case study of extrusive volcanic edifices in Yitong volcanoes. Xijian, Dagu and Dongxiao Volcanoes represent the lower part，middle part and upper part of extrusive volcanic edifices respectively. The reservoir distributions partner of extrusive volcanic edifice is analyzed by using methods of field survey, Helium injection and image analysis. Then the relationship between the geometry of columnar joint and the area density, permeability of the fractures are discussed. The results are followings. Firstly, reservoirs of extrusive volcanic edifices belong to fracture-porous type. The shrinkage fracture (columnar joint) is the most common, the vesicular and amygdule is the second most common, and the tectonic fracture is the least common. Second, reservoir is the characteristics of low-medium porosity and high permeability and is controlled by quenching and volatiles released processes. The columnar joints connect the reservoirs in the volcanic edifice. Third, the most of favorable reservoirs is tens meters in thick and locate at the upper part of the volcanic edifice. The reservoir in center belt is better than that of distal belt. The thickness ratio of reservoir to total strata is small. The drilling method of favorable targets in extrusive volcanic edifices is revealing center belt when it kept the proto-shape and is revealing flank belt when it has been undergone serious eroded. Both them only need reveal the upper part of volcanic edifices. |