Abstract:
Deepwater basins in the continental margin of the Neotethys tectonic domain are one of the important gas rich regions in the world. However, the exploration degree of deepwater oil and gas in the region is relatively low, and the main controlling factors for reservoir formation are unclear, which restricted the exploration of deepwater oil-gas resources in this region. Based on the basic geological data such as structure and stratum, progresses in deepwater gas exploration and exploitation, and the latest data of gas fields in the study area, we comprehensively analyzed the distribution of gas-ich basins and geological conditions for gas reservoir generation in deep water areas, and discussed the frontier of deepwater natural gas exploration in this region. Results show that the deepwater basins in continental margin of the Neotethys tectonic domain can be divided into three segments: east, middle, and west. The gas source rocks in the deep water area are mainly coal-bearing strata, followed by marine mudstone. The reservoirs are mainly composed of clastic rocks such as shallow marine deltaic sandstone and deep-sea turbidite sandstone. The caprocks are mainly composed of the Lower Cretaceous marine shale and Miocene-Pliocene marine mudstone. Traps are mainly structural traps. With the gradual closing-up of the Neotethys Ocean from east to west, in the Northwest Australian Shelf of the eastern segment, oil and gas are generated-stored in rifting stage and capped in passive continental margin stage, while in the Eastern Mediterranean region of the western segment, oil and gas are generated in rifting stage and stored-capped in passive continental margin stage. For those in the middle segment including the eastern and western continental margins of India, the scenarios are in-between. Controlled by the degree of oil and gas exploration in the deep-water area of the Neotethys tectonic domain, existing oil and gas discoveries, and oil and gas geological conditions, there are three major exploration zones in the continental margin deepwater area of the Neotethys tectonic domain: mature zone, semi-mature zone, and new zone.