鄂尔多斯盆地姬塬油田长8段沉积相研究

摘要

Chang 8 member of Yanchang Formation is the major reservoir in Jiyuan Oilfield.With the development of oil and gas exploration,the areal heterogeneity of the reservoir has become an obstacle for further exploration and development,so the fine sedimentary facies description is particularly significant.Based on the analysis of sediment provenance and facies indicator,it is considered that Chang 8 member of Yanchang Formation is controlled by the provenances from the northwest and northeast,experienced the transformation from delta plain to delta front,and deposited distributary channel sand body which is superimposed vertically and continuous laterally.The physical properties of Chang 81 layer under different subfacies and different sources are contrasted.The result shows that the reservoir property of delta plain in Chang 81 layer is better than that of delta front,and the reservoir property controlled by the provenance from northwest is better than that controlled by the provenance from the northeast.The favorable reservoirs of Chang 8 member are predicted,and it is considered that the reservoir in the northwest of Jiyuan Oilfield has great hydrocarbon potential.%延长组长8段是姬塬油田开发的主力油层,随着油气勘探开发程度的不断加深,其储层的平面非均质性已成为当前勘探开发的制约因素,因此对沉积相展布的精细描述显得非常重要。文中通过物源及相标志分析,认为延长组长8段受西北和东北2个方向物源的控制,经历了三角洲平原向三角洲前缘的过渡,沉积了纵向上叠置、横向上连片的分流河道砂体。在此基础上,对长81层不同亚相及不同物源控制下的砂体物性进行了对比,得出长81层三角洲平原的砂体物性比三角洲前缘的砂体物性好,受西北物源控制的砂体物性比受东北物源控制的砂体物性好。最后,对长8段有利储集相带进行了预测,认为姬塬油田西北方向的储集物性较好,具有较大的油气勘探潜力。