莱州湾凹陷河流沉积地貌形态对储层物性的影响

Effects of fluvial geomorphology on reservoir characteristics in Laizhouwan Sag

渤海莱州湾凹陷高精度三维地震数据体为其地震地貌学研究提供了可靠数据基础。通过对该区明化镇组下段的地震地貌学迭代研究,不但能在地震切片上识别出河流沉积单元形态,还可预测其储层物性分布。共识别出四个期次河道形态,测量了75处河道宽度。河道宽度的概率累积分布为储层规模评估和井距设计提供了尺度约束。采用地震相约束的多属性分析方法预测出明化镇组下段的砂体厚度、孔隙度、渗透率和含油饱和度等四个主要储层物性参数;再将此四个储层物性参数与河道形态做叠合分析,发现砂体厚度显著受单一河道形态和规模的影响,孔隙度、渗透率和含油饱和度等三参数也与各期次河道形态的分布相关联。从综合评价看,一定规模的河道分布区域,其四个储层物性参数值均优,将是明化镇组下段优先开发区域。

High-quality 3D seismic data provides a reliable base of information for seismic geomorphology study in Laizhouwan Sag.By comprehensive iterated studies of seismic geomorphology,depositional elements were identified,and consequently reservoir distribution in the area is predicted.Channel sand images of four fluvial phases are traced,and channel widths are measured at 75 points alone the channel.These channel widths might control reservoir scale.Using multi-attribute patterns constrained by seismic facies,we calculate four reservoir characteristics including sandstone thickness,porosity,permeability and oil saturation in Minghuazhen Formation.And then,we superimpose reservoir characteristics on channel morphology.We find out that sand thickness is obviously controlled by channel morphology.The porosity,permeability and oil saturation are controlled by the four fluvial phases.In inner channels,channel widths are larger and four reservoir parameter values are higher.Based on the comprehensive evaluation,channel areas are considered as favorable reservoirs for the next step exploration and development in Minghuazhen Formation.