陕北吴起地区延长组储层非均质性特征

延长油田股份有限公司 吴起采油厂,陕西 吴起 717600

储层非均质性; 成岩作用; 旋回; 鄂尔多斯盆地

Heterogeneity of the reservoir in the Yanchang Formation,Wuqi area
BAI Jiang,LIU Xiao-fang

(Wuqi Oil Field,Yanchang oil Field Corporation Limited,Wuqi 717600,China)

reservoir heterogeneity; diagenesis; cycle; Ordos Basin

DOI: 10.13800/j.cnki.xakjdxxb.2017.0315

备注

储层非均质性是造成储层砂体内部渗透率垂向及平面变化的主要因素。通过对砂岩储层中碎屑颗粒、填隙物含量等演示学特征及成岩作用的分析,利用非均质性计算指标分析吴起地区延长组储层非均质性特征。研究表明吴起地区延长组以发育长石砂岩为主,具有分成熟度高、分选好的特征,成岩作用主要表现为压实和压溶、胶结作用、交代作用和溶蚀作用,从层内非均质性、层间非均质性和平面非均质性等非均质性指标分析认为,单砂体粒度特征以正韵律、正韵律叠加和复合韵律较为发育,层理构造的垂向变化引起渗透率的垂向变化,泥质夹层、钙质夹层对油藏进行了分割,储层砂体渗透率值非均质性强的特征明显。储层非均质性差异导致吴起地区延长组砂体在平面上使得渗透率值呈北东-南西向展布,是由于不同沉积环境水动力条件变化的结果。

The heterogeneity of reservoir is the main factors of the vertical and horizontal reservoir sandbody permeability change in reservoir sandbody.Based on the analysis of the detrital grain,interstitial material and diagenesis in the sandstone reservoirs,the heterogeneity of the Yanchang Formation in the Wuqi area is analyzed using the heterogeneity calculation index.Study shows that the reservoir of Yanchang Formation is arkose sandstone in Wuqi area,which is characterized by high maturation and good sorting.The diagenesis mainly includes compaction,pressure solution,cementation,metasomatism and dissolution.The analysis of heterogeneity interlayer heterogeneity and horizontal heterogeneity shows that the characteristics of single sandbody are positive rhythm,positive rhythm superposition and composite rhythm.The vertical variation of bedding structure caused the change of permeability.The oil reservoirs were divided by the muddy interlayer and the calcareous interlayer.The heterogeneity of the permeability of the sand body is obvious.Therefore,the difference of reservoir heterogeneity causes the sandbody of Yanchang Formation in Wuqi area to make the permeability value in the northeast-southwest,which is due to the variation of hydrodynamic conditions in different sedimentary environments.