羌塘盆地第一口油气科学钻探井油气地质成果及勘探意义

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

关键词:  油气地质条件  科探井  羌塘盆地  地震解译

Key words:  Oil and gas conditions  scientific drilling well  Qiangtang Basin  Seismic interpretation

摘要:

羌塘盆地位于青藏高原腹地，是我国陆上面积最大、勘探程度最低的油气勘探新区，长期以来，由于缺乏油气科学钻探井的验证，对盆地油气地质条件认识不清。最近，中国地质调查局成都地质调查中心在北羌塘中北部的半岛湖地区组织实施了第一口深达4696.18米的油气科学钻探井—羌科1井，本文对该科探井的油气地质成果进行了报道。钻遇了从上侏罗统至上三叠统的连续地层，其中下-中侏罗统雀莫错组与下伏上三叠统那底岗日组地层为整合接触，沉积环境为三角洲-局限台地环境。羌科1井在雀莫错组中首次钻遇了烃源岩，并发现13层气测异常，其中，3层为重要含气层，此外还识别出两套重要的区域性盖层和一套直接封盖层。这些成果表明半岛湖地区油气保存条件较好，是盆地油气勘探的有利地区。

Abstract:

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.