鄂尔多斯盆地苏里格中部水平井开发区盒8段沉积微相和砂体展布

为满足鄂尔多斯盆地苏里格气田水平井部署、水平井地质导向及跟踪分析的需求,作者运用岩心观察、薄片鉴定、垂向层序和测井相分析等手段,以辫状河沉积模式为指南,汲取有关的露头和现代沉积定量储集层沉积学成果,对苏里格中部水平井开发区盒8下亚段沉积微相和砂体展布进行了精细描述。在相标志、微相特征和沉积层序研究基础上,以研究区密集井区剖面详细对比、砂体储集层厚度统计为依据,并运用水平井水平段录井资料,综合分析估算出研究区盒8下亚段储集砂体规模参数。作者拟定了沉积亚相、微相划分的3项指标(砂/地比、测井曲线、储渗砂体)。精心编制的砂层组沉积微相和砂体展布图,为水平井部署和地质导向提供了有力支撑。

Sedimentary microfacies and sandbody distribution of the Member 8 of Xiashihezi Formation in horizontal well zone,central Sulige area,Ordos Basin

In order to meet the demand of arrangement,geosteering and track of the horizontal wells in Sulige Gasfield,Ordos Basin, the core survey,thin section appraisal,and analysis of vertical sequences and electrofacies were employed. Guided by depositional models of braided river,and based on the previous research results of the outcrops and modern quantitative reservoir sedimentology, the sedimentary microfacies and sandbody distribution in the horizontal well zone of the central Sulige area has been described finely. By analyzing the facies markers, sedimentary microfacies and depositional sequences of the lower Member 8of Xiashihezi Formation,as well as the detailed comparing of crowd well zone section, the statistics of reservoir sandbody thickness,and logging date of horizontal section in horizontal wells, the size parameters of reservoir sandbody are estimated. Three indexes(sand/stratum ratio,logging curve,reservoir sandbody) were studied out used to subdivide the sedimentary facies subfacies and microfaices. A map of sedimentary micro facies and sandbody distribution,which provides strong support for the horizontal well arrangement and geosteering.