四川盆地上三叠统—侏罗系含油气系统特征及油气富集规律

根据烃源岩发育特征和油气藏类型,将四川盆地上三叠统—侏罗系含油气系统进一步划分为上三叠统含气系统和侏罗系含油系统两个子系统。以含油气系统的基本要素研究为基础,分别探讨了上三叠统含气系统和侏罗系含油系统的成藏条件、主控要素和油气富集规律。上三叠统含气系统成藏主控因素为强充注的气源、燕山期古隆起和断裂裂缝,晚侏罗—早白垩世是气藏的主要形成期。侏罗系含油系统在不同区带具有不同的成藏规律及主控因素,川中地区油气藏形成主要受油源区、古隆起、断裂或裂缝、有效储集体展布四个因素控制,主要形成裂缝—岩性油藏;巴中—平昌地区主要受生烃中心和裂缝的控制,形成岩性—裂缝油藏为主;在大巴山前缘成藏主控因素为断裂、有效储集砂体和保存条件,形成裂缝—岩性油气藏。

Characteristics of Upper Triassic-Jurassic Oil and Gas System in Sichuan Basin and Oil and Gas Abundance Law

Based on the characteristics of hydrocarbon source rock development and the types of oil and gas reservoirs, the Upper Triassic-Jurassic oil and gas system in Sichuan Basin is further divided into two sub-systems - Upper Triassic and Jurassic. Taking the fundamental elements of the oil and gas systems as the basis for the study, this article is focused on the migration and accumulation conditions, main controlling factors and the abundance law of Upper Triassic oil and gas system and Jurassic oil and gas system. The main controlling factors for migration and accumulation of Upper Triassic oil and gas system are the strong gas infill sources and the palaeohigh and faulted fractures of Yanshanian Period. Late Jurassic and Early Cretaceous are the main stages for formation the gas reservoirs. Jurassic oil and gas system has the different migration and accumulation laws and main controlling factors in the different zones and belts. The oil and gas reservoirs in Central Sichuan region are formed mainly under the control of four main factors - oil source zone, palaeohigh, fault or fracture, and extension of effective reservoir body, leading to existence of fracture-ligthologic oil reservoirs. The oil and gas reservoirs in Bazhong-Pingchang region are controlled mainly by the hydrocarbon generation center and fracture, leading to existence of lithologic-fracture oil reservoirs. The main controlled factors for the reservoirs in Dabashan frontal area are fracture, effective reservoir sandbody and storage condition, leading to existence of fracture-lithologic oil and gas reservoirs.