准噶尔盆地中部4区块侏罗系头屯河组沉积特征

Sedimentary Characteristics of Jurassic Toutunhe Formation in Block 4 Central Junggar Basin

摘要: 利用古地貌、古气候、古生物等分析了中部4区块及周缘侏罗系头屯河组沉积古环境演变，结果表明：头屯河组沉积时期古气候逐渐变干旱，物源供给量逐渐减弱，砂体沉积厚度及规模逐渐变小；利用重矿物成分的变化以及古生物及微量元素变化特征，结合地震相特征明确了侏罗系头屯河组沉积时期主要来自北东方向克拉美丽物源区以及东南方向博格达山物源区，结合单井相及古气候变化研究，头屯河组一段主要发育曲流河三角洲前缘砂体，厚度相对较大，范围较广，头二段沉积时期主要发育水下分支河道砂体，在平面上呈现河道形态，头三段时期砂体不发育。

Abstract: The palaeogeomorphology, palaeoclimate and Palaeontology are used to analyze the evolution of sedimentary palaeoenvironments of the Toutunhe Formation in the central four blocks and the surrounding Jurassic. The results show that the palaeoclimate of the Toutunhe Formation gradually dried up during the sedimentary period, the supply of provenances gradually weakened, and the thickness and scale of sand body gradually decreased. According to the characteristics of Paleontology and trace elements, the sedimentary period of Toutunhe Formation in Jurassic is mainly from the north-east to Kelamei provenance area and the southeast to Bogda Mountain provenance area. Combined with single well facies and paleoclimate change, meandering river delta front sand bodies are mainly developed in the first member of Toutunhe Formation. The sand bodies of the first and second members are mainly underwater branching channels and bodies, showing channel morphology in plane, and the sand bodies of the first and third members are not developed.