晚古生代构造—沉积分异对四川盆地二叠系多类型气藏的控制作用

基于晚古生代全球构造背景和上扬子地区构造环境、盆地原型及四川盆地二叠纪岩相古地理的分析，结合二叠系气藏特征和成藏条件认识，探讨了晚古生代构造—沉积分异对四川盆地二叠系多类型气藏的控制作用。结果表明，伸展背景下构造差异隆升或沉降形成隆凹相间的古地貌，导致四川盆地中二叠世—晚二叠世经历早期台地与台凹相间，晚期台地与裂陷槽(陆棚)相间的沉积格局的演化，台凹、潮坪—潟湖、斜坡、陆棚—盆地等相区(亚相—微相)控制发育的多套、多类型烃源岩，与受台地边缘礁滩、台内浅滩控制及后期成岩作用改造形成的多套、多类型储层构成下生上储、旁生侧储、自生自储等多种高效源储组合，构建了二叠系成藏的基本条件；多套、多类型储层是二叠系含气层系多、气藏类型多的根本原因。二叠系具备多领域、多类型、多层系综合、立体勘探的有利条件。

Controlling effect of Late Paleozoic tectonic and sedimentary differentiation on multi-type gas reservoirs in Permian,Sichuan Basin

Based on the analysis of the Late Paleozoic global tectonic background and the tectonic environment of the Upper Yangtze area, the basin prototype and the Permian lithofacies paleogeography of the Sichuan Basin, combined with the understanding of the Permian gas reservoir characteristics and accumulation conditions, the controlling effect of the Late Paleozoic tectonic and sedimentary differentiation on the Permian multi-type gas reservoirs in the Sichuan Basin is discussed. Results showed that the tectonic differential uplift or subsidence under the extensional background formed the palaeogeomorphology of alternating uplift and depression, which led to the evolution of the sedimentary pattern from the Middle Permian to the Late Permian: platform alternating with platform and depression in the early stage, and platform alternating with rift trough (shelf) in the late stage. Multiple sets and types of source rocks formed in the platform sag, tidal plane-lagoon, slope, shelf-basin and other facies, sub-facies or micro-facies, and multiple sets and types of reservoirs controlled by beaches, platform edge sand and later diagenesis transformation constituted a variety of source-reservoir combinations such as lower generation and upper storage, side generation and side storage, self-generation and self-storage etc. These source-reservoir combinations constitute the basic conditions for hydrocarbon accumulations in Permian. Multiple sets and types of reservoirs are the fundamental reasons for the wide distribution of Permian gas-bearing strata and various gas reservoir types. The Permian strata has favorable conditions for comprehensive and three-dimensional exploration owing to multi-domain, multi-type and multi-layer.