浅水三角洲分流水道储层构型表征与完井方式选择

Architecture characterization and completion mode selection for the reservoirs of distributary channel of shallow-water delta

为了提高BZ19-4油田单井产量和油藏采收率,开展了浅水三角洲水下分流河道储层构型剖析以及水平井完井方式研究。利用地震、岩心和测录井资料,在构型模式指导下,以垂向分期为重点,分层次对研究区明下段浅水三角洲分流河道进行构型表征;依据构型特征,建立起水平井轨迹与填积层的配置关系模式,结合窄厚条带状砂体特点,进而优化完井方式。结果表明:浅水三角洲水下分流河道可分为复合水道、单一水道和河道内部填积体3个构型层次;复合水道可靠地震资料识别,其宽度为400~1 100 m,厚度为10~40 m;单一水道层次通过组合模式分析及边界识别,得出其宽度为250~350 m,厚度为2~9 m;单一水道内部构型单元通过岩电特征研究及模式认知识别出填积体和填积层2个构型单元。采用水平井深穿透射孔方式完井能有效沟通浅水三角洲填积层上部与下伏的厚储层,为油井增加产量提供了建议。

To increase the single-well production rate and oil reservoir recovery factor of BZ19-4Oilfield,the reservoir architectures of underwater distributary channel of shallow-water delta were dissected and the completion modes of horizontal wells were investigated in this paper.Based on the seismic,core,mud log and logging data,the architecture of distributary channel of shallow-water delta in the Lower Member of Minghuazhen Formation in the study area was characterized layer by layer with the vertical stage as the focus according to the architecture mode.Then,the allocation relationship model between the horizontal well trajectory and the aggradation layer was established on the basis of the architecture characteristics.And finally,combined with the characteristics of narrow and thick banded sandbody,the well completion mode was optimized.It is indicated that underwater distributary channel of shallow-water delta can be divided into three architecture layers,i.e.,complex channel,single channel and aggradation body inside the channel.The complex channel can be identified on the basis of seismic data,and it is400-1100m wide and10-40m thick.The single channel can be identified by using combination mode analysis and boundary identification,and it is250-350m wide and2-9m thick.The internal architecture unit of the single channel can be identified by means of rock electric characteristic investigation and mode cognition,and two architecture units are identified,including aggradation body and aggradation layer.The upper part of shallow-water delta aggradation layer is connected effectively with its underlying thick reservoir in the completion mode of horizontal well with deep-penetration perforation.It provides the suggestions for the stimulation of oil wells.