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Discovery from Exploration of Lower Paleozoic-Sinian System in Central Sichuan Palaeo-uplift and Its Natural Gas Abundance Law

Luo Bing, Zhou Gang, Luo Wenjun, Xia Maolong   

  1. Exploration and Development Research Institute of PetroChina Southwest Oil and Gas Field Company
  • Online:2015-03-15 Published:2015-05-21

Abstract: Fresh breakthrough has been recently made in natural gas exploration of Sinian Dengying Formation and Cambrian Longwangmiao Formation in central Sichuan palaeo-uplift. A giant gas field, with three vertically-distributed producing layers, was found in the eastern segment of the palaeo-uplift. The proven natural gas reserve of Longwangmiao Formation exceeds 4400×108m3 while the controlled gasbearing area of the 4th member of Dengying Formation is 7500 km2. The study indicates that the giant gas field of central Sichuan palaeouplift is characterized in aged production layers, large buried depth, a multiple of gas horizons, a multiple of gas reservoir types and large scale. A number of factors helped development of this gas field, such as superimposition of extensive high-quality source rock and largearea karst reservoirs, existence of large-scale stable palaeo-uplift, and composition of ancient and modern structural traps. The more crucial factor is that successive development of palaeo-uplift matches with various accumulation elements. The high position in the eastern segment of central Sichuan palaeo-uplift is the favorable zone for natural gas abundance, where the marginal area of the south-north ribbon-shaped zone from Gaoshiti to the western part of Moxi is the high-yield natural gas abundance zone of Dengying Formation. The composition area of Moxi-Longnvsi ancient and modern structures is the high-yield natural gas abundance zone of Longwangmiao Formation.