乌干达K油田扇三角洲沉积正演模拟与应用

乌干达K油田位于Albert盆地,由于钻井数较少,地震资料品质差,沉积储层空间分布预测存在严峻挑战.根据岩心、测井、古生物、重矿物、粒度分析等资料综合分析后认为,乌干达K油田属滨浅湖环境,发育受边界断层控制的近源扇三角洲沉积,物源方向位于油田东南部,以低能长期的水下分流河道牵引流搬运为主.在沉积主控因素定量分析的基础上,将可容纳空间变化、物源供应及沉积物搬运等参数定量表征,并在年代地层框架约束下,通过正演模拟,再现地质历史时期地层沉积演化过程,建立了三维储层砂岩分布概率模型,进一步认识了研究区各层砂体的空间分布特征.将沉积演化模拟的砂岩分布结果转化为三维地质建模的定量控制条件,对沉积相模型进行约束,建立了更符合沉积认识的高精度相控地质模型,实现了扇三角洲储层砂体定量预测与表征.

Sedimentary Forward Simulation and Application of Fan Delta in K Oil Field in Uganda

Due to the poor quality of seismic data and few wells, it is full of challenge to predict reservoir distribution in K oil field which is located at the south of Albert basin in Uganda. According to the comprehensive analyses of core, well logging, paleontology, heavy minerals and grain size, K oil field in Uganda is a shallow lake environment and developed near the source fan delta controlled by bounding fault. The direction of the sediment source located at southeast of this field and it was supplied by predominant distributary channel traction current in low energy and long term. On the basis of quantitative analysis of sedimentary impact factors, the quantified accommodation space variation, sedimentation supply and sediment transportation were put into sedimentary forward simulation under the control of chronostratigraphic framework to reconstruct stratigraphic evolution progress in geological history. Thus a three-dimension reservoir sand proportion distribution model was constructed to facilitate further understanding the spatial distribution characteristic of the sand in each zone. After transforming the results of sedimentary forward simulation into quantitative constraints for 3D geological modeling to control the facies model, a more accurate geological model which is consistent with the high accuracy of the sedimentary concept is established to predict and characterize the fan delta reservoir sand quantitatively.