| PDF: | |
| Time: | 2015 |
| Journal: | Acta Petrolei Sinica |
| Volumn: | 34 |
| Issue: | 5 |
| Pages: | 896-904 |
| Type: | EI |
| Author: | Yanquan Wang,Daqian Hu,Guogang Cai,Pujun Wang,Xiaojian Yu |
Abstract: | Four factors including faults, volcanic eruption cycles, lithofacies and lithology were mainly concerned about porosity and permeability in volcanic reservoirs from eastern depression of the Liaohe Basin, NE China. Data base involved in the research include well-logs and corresponding geological description of 21 boreholes, analytical results of porosity and permeability of 193 rock samples, 3D seismic of the region, and structure-lithofacies mapping. 11 types of volcanic rocks were recognized and among them trachyte is the best for reservoirs development. 5 lithofacies and 14 sub-facies were classified and the extrusive facies are the most favorable ones for effective volcanic reservoirs. 5 cycles developed in the volcanic rocks, reservoir formation mainly concentrated in cycle 3, which is in the middle of volcanic cycles. The reservoir spaces can be grouped into 2 types of primary and secondary, which can be subdivided into 9 sub-types and 14 species. Fractures of tectonic origin are the main controlling factor on permeability. Effective reservoirs are actually optimizing combination of the four factors of fracture, eruption cycles, lithofacies and lithology. Volcanic reservoirs concentrated within and around the large-scale strike-slip fault zones, especially in the conjunction of main fault and its conjugate branch. Furthermore, faults control the spatial distribution of the volcanic rocks and the development of secondary fractures. Eruption cycles control the vertical distribution of effective volcanic reservoirs. Lithofacies control reservoirs scale and primary pores development. Lithology determine the types of reservoir spaces and the intensity of alteration resulting in secondary porosity. |