Seismic Identification and Hydrocarbon Accumulation Characteristics of Submarine Fan in offshore Suriname

Abstract

In recent years, oil and gas fields have been continuously discovered in the Suriname-Guyana Basin of South Atlantic, the reservoir of which is submarine turbidite sandstone and become one of the hot exploration objectives in the world. Based on the interpretation and analysis of 2D seismic and well data, this paper presents the integrated geological and geophysical evaluation of the Suriname-Guyana basin within Suriname and describes the identification characteristics and hydrocarbon accumulation process of submarine fan in offshore Suriname. The tectonic evolution of this region can be divided into four stages, breakup of Pangea, intracontinental rift, regional uplift and drifting over the South Atlantic. The Upper Cretaceous marks the transition of a transgressive to a regressive system with increasing sediment input from the south west, creating a broad delta plain environment across the shallow offshore area. It has been confirmed that multi-stage submarine fans have developed from Upper Cretaceous to Neogene in offshore Suriname, with overlapping characteristics of multiple erosive surfaces. It is suggested that erosive surface forming local unconformity is the important identification mark of submarine fan. Among them, the Paleogene and Upper Cretaceous submarine fans are the most widely distributed and have the most obvious characteristics on seismic profiles. The bottom of the Paleogene and Upper Cretaceous fans are identified by the erosive surfaces. The fan root has obvious characteristics of cutting valley, forming inter-bedded with the deep-sea facies toward the outer fan, along with litho-logic granularity thinning and scope expansion. The distal parts of the submarine fan are surrounded by abyssal shale, which can form a good source, reservoir and cap configuration. Therefore, turbidite fan sandstone with good source rock and cap configuration is the favorable reservoir.