鄂尔多斯盆地姬塬地区长8储层致密与成藏关系研究

发布时间：2018-05-19 05:56

  本文选题：姬塬地区 + 致密砂岩储层　； 参考：《长安大学》2015年博士论文

【摘要】：鄂尔多斯盆地姬塬地区延长组长8储层是典型的致密砂岩储层,储层致密与油气充注成藏关系的研究对认识该区石油富集规律及指导勘探开发部署具有一定的理论和现实意义。论文以岩芯观察为基础,综合应用岩石薄片、铸体薄片、扫描电镜、粒度分析、X衍射、常规压汞、恒速压汞、电子探针、碳氧同位素、油气包裹体等多种分析测试资料,对储层岩石学及储集性能、成岩作用特征以及储层致密与油气充注成藏关系进行研究,揭示相对优质储层的主控因素,建立研究区致密砂岩储层的综合评价标准,对储层进行评价预测。研究表明,姬塬地区长8储层以细粒长石岩屑砂岩和岩屑长石砂岩为主,填隙物含量较高,岩石总体成分成熟度低、结构成熟度中等。储层孔隙度平均为8.67%,渗透率平均为0.46×10-3μm2,物性总体为低孔超低渗。储层孔隙结构可划分为4种类型,以Ⅱ类较低排驱压力—小孔喉型占主导地位。储层孔隙半径主要分布(80~250)μm之间,属于大孔隙的范畴。随着渗透率增加,喉道半径分布范围变宽,而孔喉半径比分布高值比例减小。储层物性与分选系数、最大进汞饱和度、孔隙和喉道进汞饱和度为正相关性,与结构系数为负相关性。研究区长8储层成岩作用类型丰富复杂,主要包括压实、胶结、溶蚀等作用。成岩演化普遍达到中成岩阶段A期。定量计算视压实率平均为0.42,视胶结率平均为0.58,压实和胶结强度均为中等偏强。视溶蚀率平均为0.34,为中等强度溶蚀。确定静水条件下浮力运移的临界喉道半径上限为0.592μm,推算储层致密的孔隙度上限为12%。孔隙演化定量计算表明,压实后剩余孔隙度分布在19.7%~25.56%之间,胶结作用后孔隙度普遍小于12%。压实作用造成原生孔隙大量减少,而晚期胶结作用是造成研究区长8储层致密的根本原因。储层致密与油气充注成藏时序关系研究表明,中侏罗世之后,低熟油气开始逐渐形成并充注,在早白垩早期油气小规模成藏,早白垩世中期油气大规模充注成藏,油气大规模成藏与姬塬地区长8储层致密同时进行。致密砂岩储层在整体低孔、低渗的背景上仍发育部分相对优质储层,其控制因素有沉积作用、成岩储集相及构造裂隙等。在常规储层评价基础上,优选排驱压力、孔隙结构类型、喉道半径等反映致密砂岩储层孔隙结构特征的新参数,建立储层的综合评价标准,预测研究区内优质储层的分布,指导下步的勘探开发部署。
[Abstract]:Yanchang formation 8 reservoir in Jiyuan area of Ordos Basin is a typical tight sandstone reservoir. The study on the relationship between reservoir density and oil and gas accumulation is of theoretical and practical significance in understanding the law of oil enrichment and guiding exploration and development in this area. On the basis of core observation, the paper synthetically applies various analytical and testing data, such as rock thin slice, cast thin piece, scanning electron microscope, particle size analysis X diffraction, conventional mercury injection, constant velocity mercury pressure, electron probe, carbon and oxygen isotope, oil and gas inclusion, etc. The petrology and reservoir properties, diagenesis characteristics and the relationship between reservoir compactness and oil-gas filling and reservoir formation are studied, the main controlling factors of relatively high quality reservoirs are revealed, and the comprehensive evaluation criteria for tight sandstone reservoirs in the study area are established. The reservoir is evaluated and forecasted. The results show that the Chang 8 reservoir in Jiyuan area is dominated by fine feldspar lithic sandstone and lithic feldspathic sandstone with high content of interstitial matter low maturity of the total composition of rock and moderate structural maturity. The average porosity and permeability of the reservoir are 8.67 and 0.46 脳 10 ~ (-3) 渭 m ~ (2), respectively. The pore structure of the reservoir can be divided into four types, and the type 鈪，

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