Reservoir-forming characteristics and differential enrichment law of middle-shallow natural gas of Shaximiao Formation in Tianfu gas field in Sichuan Basin
Using the Shaximiao Formation of the Tianfu gas field in Sichuan Basin as an example,this study establishes a natural gas accumulation model by analyzing the origin of natural gas,transport system,and the processes of migration and accumulation.It reveals the mechanisms of natural gas migration and accumulation,along with the key controlling factors for high yields and enrichment.The results show that the natural gas in the Shaximiao Formation is primarily coal-derived gas from the Xujiahe Formation,with oil-type gas from the Lower Jurassic sources present in the northeastern area.The transport of oil and gas by faults is characterized by"dominance,supplementation,and regulation".Four gas migration and accumu-lation modes were identified:strong gas migration and accumulation with external sources via reverse faults,moderate gas mi-gration and accumulation with external sources via reverse faults,moderate gas migration and accumulation with mixed sources via normal and reverse faults,weak gas migration and accumulation with self-sourced gas via normal faults.The rela-tionship between fault-source configurations,fault-sand configurations,paleotectonic structures during critical periods,and variations in channel reservoirs are the main factors controlling natural gas migration,accumulation and differential enrich-ment.These findings deepen the understanding of the accumulation and enrichment of middle-shallow natural gas in Sichuan Basin and provide valuable insights for the exploration and development of middle-shallow natural gas in similar areas.
middle-shallow gasorigin of natural gasnatural gas migrationaccumulation patternmain controlling factors of enrichmentSichuan Basin
万方数据
维普
