Study On Basin-Range Coupling & Petroleum Accumulation In The East Region Of Tarim Basin

Tarim Basin is a huge and superimposed basin, which was formed by the polymerization of cratonic basin, rift basin and foreland basin. From the Sinian Period to the Quaternary Period, many different tectonic settings had been undergone, and paleohigh, as well as extensional, thrust and strike-slip structures had developed. Various types of prototype basins filled in different sedimentary sequences, forming various types of hydrocarbon systems and evaluation units. In the eastern Tarim Basin, there is a Mesozoic ~ Cenozoic basin held between Tianshan Mountain and Altun Mountain, constituting the mountain-basin coupling; and the pericratonic basin environment existed during the early Paleozoic Era, which should be the strategic superseding area for hydrocarbon exploration in Tarim Basin for the near future. Aiming at the geodynamic environment, this paper further analyzes the sequence framework and hydrocarbon systems of prototype basins in the east Tarim region. In addition to regarding the hydrocarbon basin –hydrocarbon system –hydrocarbon block –hydrocarbon trap as one complete system for study, it classifies the exploration strategy and evaluation into four levels. Based on lots of actual data and in combination with the exploration practices within the region, this paper presents the following 12 main progress and understanding points concerning 4 aspects: 1. Establishment of a formation sequence framework for the eastern Tarim region 1) the rift basin sequence was formed during the early stretching period (South China Period ~ Sinian Period); 2) the cratonic basin sequence was formed during the mid-stable development period (Paleozoic Era); 3) in the late alternative period of tectonic superimposed and stretching, the alternative foreland sequence and the post-orogenic sequence was formed, accompanied with strike-slip basin sequence (Mesozoic Era, and Cenozoic Era). Since the Sinian Period, Tarim Basin has experienced different types of basin evolution stages. Hence, the sequence infill established on different tectonic background can be used as the basis for various types of hydrocarbon systems. However, the Cambrian ~ Ordovician sedimentation in the east Tarim region is different from the central and west Tarim regions. The latter is featured by intra-cratonic basin platform-facies carbonate deposit, while the former is characterized by peri-cratonic basin shelf-slope facies turbidite deposit. 2. Basin evolution and basin-mountain coupling The evolution of Tarim Basin is controlled by the development of oceanic cycle and continental cycle: 4) Divergent stage: Tarim plate was separated from the supercontinent, forming the South China Period ~ Sinian rift; 5) Drifting stage: the Paleozoic cratonic basin was formed through drifting –...