Petroleumgeological achievements and exploration significance of the first oil and gas scientific drilling well in the Qiangtang Basin

The Qiangtang Basin is located in central Qinghai-Tibet Plateau, which is a new oil and gas exploration area with the largest area and the lowest level of exploration in China. Oil and gas geological conditions are unclear in this basin due to lack of validation of oil and gas scientific drilling wells. Recently, QTKT1 well was drilled by Chengdu Center, China Geological Survey in the Northern Qiangtang Depression with a depth of 4696.18 m. This paper reports the petroleum geological achievements of the well. The Quemo Co Formation conformably overlies the Upper Triassic Nadi Kangri Formation in the Badao Lake area suggesting an early-middle Jurassic age. Mudstones and gypsum were well developed in the Quemo Co Formation, suggesting delta-restricted platform environments. The QTKT1 well penetrated the Quemo Co Formation source rocks firstly, although they are poor source rocks. Shoal on edge of platform was identified on the southwest of the QTKT1 well with an area of 42.4 km², where is a favorable target for oil and gas exploration in the future. Thirteen gas logging abnormal zones and two important regional caps were identified in the QTKT1 well. These data suggest that the Bandao Lake area exhibit good oil and gas preservation conditions and is a favorable area for oil and gas exploration in the basin.