河流相储层刻画与垂向非均质性分析——以西湖凹陷C油田柳浪组为例

Fluvial reservoir characterization and vertical heterogeneity analysis:taking Liulang Formation of C Oilfield in Xihu Depression as example

西湖凹陷C油田浅层柳浪组河流相储层叠置样式复杂,非均质性强,海上油田钻井少,井间距较大,井间砂体分布预测难度大。基于三维地震和钻井岩心、测井资料,在建立等时地层格架的基础上,利用岩心相—测井相分析、等波形层位解释、有色反演、地震属性分析、河道砂体叠置正演分析等技术,对柳浪组储层进行精细刻画。结果表明:柳浪组为近南北向的辫状河—曲流河沉积体系,可划分为1个长期旋回、2个中期旋回、5个短期旋回;辫状河宽度为1.5~2.2 km,曲流河宽度为0.5~1.5 km;其中LL5段早期河道和晚期河道在开发靶区相互叠置,建议沿晚期河道布置水平井开发。该结果对研究区储层评价具有指导意义,可为其他地区河流相储层刻画提供参考。

The fluvial facies reservoirs in the shallow Liulang Formation of C Oilfield in Xihu Depression are characterized by complex superposition pattern and strong heterogeneity.There are few wells in offshore oil fields and well spacing is large.It is difficult to predict the distribution of sand bodies between wells.In order to reveal the sand body distribution of Liulang Formation,based on 3D seismic data,core data and log,combined with the sequence stratigraphy,core-logging facies and seismic facies analysis,stepwise spectral inversion,equal-waveform horizon interpretation,seismic attribute analysis,and cutting and laminated forward modeling were studied in detail.The results showed that Liulang Formation were fluvial depositional environment.The sequence stratigraphy was divided into 1 long-term cycle,3 middle-term cycles and 5 short-term cycles.Braided rivers were 1.5 to 2.2 km wide and meandering rivers were 0.5 to 1.5 km wide.The early channel's sand body and the late channel's sand body superimposed in the development area.It is suggestive to design horizontal wells along the late channel to development the reservoirs.The research results have guiding significance for reservoir evaluation in the study area.And it can provide reference for characterization of fluvial reservoir in other areas.