准噶尔盆地乌尔禾油田百口泉组冲积扇沉积特征及油气勘探意义

Characteristics of Alluvial Fan in Baikouquan Formation of Wuerhe Oil Field in Junggar Basin and Petroleum Prospecting Significance

通过分析岩心、铸体薄片及测井等资料,认为准噶尔盆地乌尔禾油田百口泉组发育一套典型的退积型冲积扇沉积。百口泉组中下部发育扇中亚相,上部发育扇缘亚相,反映研究区在三叠纪早期,湖平面逐渐升高,可容空间与沉积物补给速率比值(A/S比值)逐渐增大的沉积特征。沉积微相类型包括辫状河道充填、筛状沉积、泥石流沉积及片流沉积。综合构造、测试及试油等资料,认为扇中亚相辫状河道充填为油气富集的有利储集相带,控制了油气富集的规模与油藏边界。在有利相带控制油藏分布的结论指导下部署钻探的多口评价井在百口泉组均获得工业油流,有效地指导油田现场生产。

Through the analysis of core,cast thin slice and wireline logging data,a typical retrograding sequence alluvial fan is found in Baikouquan Formation of Wuerhe Oilfield which is located in the Junggar Basin.Mid-fan intrafacies is developed in the lower-middle part of affuvial fan and end-fan intrafacies is developed in the upper part which remark the sedimentary environment that A/S（the ratio of available accommodation and sediment flux rate） increased under a transgression of the lake water body at early Trias.Microfacies include braided channel filling,sieve deposit,mud-rock flow deposit and sheet deposit.Integrated with regional structure style,well testing data and production rate,braided channel filling in mid-fan intrafacies is the most favorable facies which controls hydrocarbon＇s accumulation and reservoir boundary.After the study,more appraisal wells were designed and drilled according to the distribution of favorable facies,and considerable hydrocarbon output in Baikouquan formation proved the accuracy of the conclusions.The laws summarized in this study will play an important role in the development of the reservoir for other oilfields.