大牛地气田下石盒子组基准面旋回与储层流动单元的层次性

运用高分辨率层序地层学原理，通过对大牛地气田下石盒子组中、短期基准面旋回的识别及等时地层格架的建立；在等时地层格架内开展了砂体对比及其空间分布特征分析；并在基准面旋回与流动单元层次性分析的基础上选取孔隙度、渗透率和含气饱和度等三个参数，将流动单元划分为A、B、C、D四种类型，分析了隔挡层类型、小尺度流动单元的垂向叠置样式与侧向分割性，探讨了流动单元与基准面旋回的关系。认为:①不同级次基准面旋回与A/S值直接控制砂体与流动单元的垂向叠置与侧向分割样式；②基准面旋回直接控制小尺度流动单元的类型、发育位置、规模及横向连通性；③在LSC2长期旋回内，随着可容空间和A/S值的增加，中期旋回流动单元的类型呈现由劣到优的变化趋势；④在中、短期基准面旋回内，随着可容空间及A/S值的增加，流动单元的发育程度和类型变差，垂向厚度变小、横向延伸距离变短、侧向上的连通性也变差。

Relationship Between Base-Level Cycles and Hiberarchy of Reservoir Flow Units of Lower Shihezi Formation in Daniudi Gas Field

A correlation between sand bodies and analysis of their spatial distribution within an isochronous stratigraphic correlation framework, which is established, based on identification of medium term and short term sase level cycles in Lower Shihezi Formation in Daniudi gas field, according to the high resolution sequence stratigraphy concept. Flow units are subdivided into A, B, C and D types in a downgrade order in terms of porosity, permeability and gas saturation parameters, which are obtained from analyzing the datum cycles and hierarchy of the flow units. In addition, types of barriers separating flow units, vertical superimposition and lateral separation patterns of small sized flow units are analyzed and the relationship between the flow units and base level cycle is discussed. It is believed that: ①the vertical superimposition and lateral separation of sand bodies and flow units are directly controlled by various grades of base level cycles and A/S values; ②The base level cycles have directly controls over types, location, scale and lateral connection of vertical superimposition and lateral separation patterns of small –sized flow units; ③In the long term LSC2 cycle, the types of flow units in a medium-term cycle tend to upgrade with increased accommodations and A/S values; ④In medium term and short term base level cycles, as accommodations and A/S values increase, flow units have deteriorated development and types, with less vertical thickness, shortened lateral extending distance and poor connections.