鄂尔多斯盆地华池地区长6油层组湖底扇内深水重力流沉积特征

以岩心的详细观察与测井录井资料综合分析为基础,通过岩石学特征和原生沉积构造等沉积相标志分析,确定鄂尔多斯盆地华池地区长6油层组厚层块状砂体属于半深湖内的深水重力流沉积体系。划分出内扇、中扇和外扇3个亚相,该区主要以中扇亚相最为发育;在深水重力流中识别出液化沉积物流、砂质碎屑流、近源浊流和远源浊流等沉积类型,建立了湖盆深水重力流沉积模式。砂质碎屑流沉积最为广泛,砂体厚度大,连片发育,具有最好的储集层物性,含油性好,是华池地区长6油层组最有利的储集层。

Characteristics of deep water gravity flows sediments in sublacustrine fan of the Chang 6 interval of Yanchang Formation in Huachi area,Ordos Basin

Base on core observations, well logging and logging, and analyses of sedimentary facies such as petrologic characteristics and primary sedimentary structures,the thick-bedded massive sand bodies of the Chang 6 interval of Yanchang Formation in the Huachi area belong to gravity flow sediments in deep lake. Three types of subfacies are recognized, i.e., inner fan,middle fan and outer fan facies, with the middle fan mainly developed in huachi area. Four sedimentary types, i.e., fluidized sedimentary flows,sandy debris flows,proximal and distal turbidity currents are identified, while the mode of deep water gravity flow in sublacustrine is reconstructed. The deposition of sandy debris flow is the most widely distributed in local area. The sand bodies of sandy debris flow always have the best reservoir physical properties and are the most favorable reservoirs in the Chang 6 interval of Yanchang Formation in Huachi area.