| PDF: | |
| Time: | 2007 |
| Journal: | Journal of Jilin University (Earth Science Edition) |
| Volumn: | 37 |
| Issue: | 6 |
| Pages: | 1232-1243 |
| Type: | Other |
| Author: | Bin Zhang,Pujun Wang,Rixin Ding,Zhongjie Xu |
Abstract: | Here reservoir geologic model refers to the spatial distribution characteristics of lithology, lithofacies and porosity & permeability for reservoir volcanic rocks. Field sections and two drilling wells are studied in detail here, reservoir units are divided and compared, and thus the volcanic reservoirs of the area are finally quantified and characterized. Volcanic facies sequence in the area under study is mainly effusive facies→ explosive facies→ effusive facies & extrusive facies→ volcanic sedimentary facies→ explosive facies→ volcanic conduit facies & effusive facies. Explosive facies and effusive facies are of the largest scales, with lateral ranging of some subfacies from 400 m to 4 000 m and thickness of a single layer ranging from 2 m to 130 m. Volcanic conduit facies, extrusive facies and volcanic sedimentary facies are smaller, lateral range is from 110 m to 1 500 m and thickness of single layer is from 3m to 85 m. According to volcanic reservoir classifying standards, the lower member of the Yingcheng Formation is the first and third grade, the 1st member is the first and second grade, with the fourth grade, the 2nd member is the first grade, and the 3rd member is interbedded by the first, second and third grades with thin layers of the fourth grade. The upper subfacies, volcanic neck subfacies and inner subfacies are the best volcanic reservoirs. The lower subfacies and hydrothermal breccias subfacies are better volcanic reservoirs, the explosive facies is middle, and the middle subfacies and volcanic sedimentary facies are bad volcanic reservoirs. Porosity and permeability of volcanic lavas would be slightly affected by their buried depth, while pyroclastic rocks would be getting worse with increasing buried depth. Volcanic rocks with low porosity and low permeability would be affected little by their buried depth. |