Sedimentary characteristics and model of shallow sea sandy debrisflow: A case study of Ying Ⅱ Member in the Dongfang 1-1 Gas Field, Yinggehai Basin

Abstract

There is shallow sea sandy debris flow in Ying Ⅱ Member in Dongfang 1-1 Gas Field, Yinggehai Basin.Based on the detailed description of cores, combined with well logs, seismic section, geochemical experiments and the research progress of gravity flow, the core, logging and seismic facies characteristics of shallow sea sandy debris flow in the study area are determined.By analyzing the sedimentary background of the study area, the sedimentary mechanism of shallow sea sandy clastic flow in ⅡL and ⅢU gas groups of Ying Ⅱ Member in Dongfang Gas Field is further discussed.It is found that it is characterized massive sandstone rich in mudstone floating debris and "mud-coated intraclasts", which are typical sandy clastic flow characteristics, in core facies, funnel type and bell-funnel type which jugged acutely in logging facies, medium amplitude parallel sheet reflection and low frequency parallel sub parallel blank reflection in seismic facies, sheet and flat lenticular distribution on the section.The results show that the sandy debris flow in the study area is the sedimentary mechanism of the shallow sea sandy debris flow formed by the combined action of the west delta front sediment collapse and re-transportation caused by the storm and the Red River flood gravity flow on the north side.

Keywords

• shallow sea sandy debris flow
• sedimentary characteristics
• "mud-coated intraclasts"
• yinggehai basin
• dongfang 1-1 gas field
• ying ⅱ member