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- Title
川西南地区二叠纪火山岩储层类型及其主控因素分析.
- Authors
熊绍云; 史志伟; 王尉; 张豪; 刘冉; 苏旺; 李亚; 姚倩颖; 张建勇; 江青春
- Abstract
As an important reservoir type in Southwest Sichuan, Permian volcanic rocks have become one of the research hotspots in recent years. Through the analysis of the porosity and permeability from Permian volcanic rocks in Southwest Sichuan, it is found that the trachyte andesitic pyroclastic rock reservoir of explosive facies pyroclastic flow subfacies is the best, followed by the self broken breccia of the upper subfacies in overflow facies and the trachyte basaltic fused pyroclastic rock of explosive facies. The porosity and permeability of lava reservoirs are poor. Through core, outcrops and microscopic observation, the reservoir space of volcanic rock is mainly dissolution holes and fractures, and the intergranular micropores of albite make a great contribution to the reservoir of trachy and esitic fused tuff. Volcanic rock facies are the basis of reservoir development. The upper subfacies of overflow facies and explosive facies are similar. Pyroclastic flow sub-middle source accumulation is a favorable facies belt for reservoir development. The reservoir heterogeneity of pyroclastic flow sub-middle source accumulation is strong, and the reservoir physical properties in the upper and lower parts of each eruption unit are better than those in the middle. Through condensation consolidation diagenesis and hydrothermal process, the porosity of trachytic basaltic fusion breccia and self broken breccia in the upper subfacies of overflow facies decreases rapidly from 25%-30% to 5%-10%; Due to the formation of a large number of intergranular micropores of albite offsetting part of the pores lost in this diagenetic process, the porosity of trachytic andesitic fused tuff lost about 10% during this diagenesis. Low temperature and low salinity inclusions reveal that the first stage calcite and quartz cements in the reservoir pores were formed in shallow to medium burial after the volcanic eruption stopped, the organic matter was immature to low mature, there was no large-scale hydrocarbon expulsion, and the dissolution of organic acids to the reservoir was limited; It shows that weathering and leaching in the early epigenetic rock stage is the key to reservoir improvement and preservation. The burial stage is the stage of continuous hole filling, and the improvement of reservoir by organic acid dissolution is limited.
- Subjects
ANDESITE; VOLCANIC ash, tuff, etc.; TRACHYTE; VOLCANIC eruptions; ORGANIC acids; BRECCIA; QUARTZ; WATER salinization
- Publication
Natural Gas Geoscience, 2022, Vol 33, Issue 6, p899
- ISSN
1672-1926
- Publication type
Article
- DOI
10.11764/j.issn.1672-1926.2022.02.001