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

Key words: 
• baselevel cycle /
• reservoir flow unit /
• hiberarchy /
• Lower Shihezi Formation /
• Daniudi gas field

Abstract: 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 sma
ll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.