Developmental characteristics and oil control of Indosinian paleo-uplifts in West Sichuan Depression, Sichuan Basin

The paleo-uplift of a basin is of great significance for the positioning of oil and gas fields. In this paper, the characteristics of the Indosinian paleo-highs in the West Sichuan Depression of the Sichuan Basin were studied in combination with the newly completed 3D seismic and drilling data. The study showed that in the Indosinian epoch in the western Sichuan area, not only the east-westward prototype of the uplift in the Xiaoquan-Xinchang-Fenggu area, but also the north-eastward "beaded" paleohighs in front of the Longmen Mountain and in the West Sichuan Depression developed. Seismic attributes revealed that the Indosinian paleo-uplift had significant control over the distribution of fractures on the top of Leikoupo Formation and the development of karst reservoirs. Considering reservoir distribution characteristics, paleo uplift and reservoir overlap, hydrocarbon source conditions and fracture migration channels, it was concluded that in addition to large tectonic uplift zones and slope zones, the Indosinian paleo-uplifts in the West Sichuan Depression might be favorable for hydrocarbon exploration.