高分辨率层序地层学在储层宏观非均质性研究中的应用——以松辽盆地朝阳沟油田朝1—朝气3区块扶余油层为例

运用高分辨率层序地层学原理和方法,在朝阳沟油田朝1—朝气3区块扶余油层识别出41个短期、7个中期基准面旋回及2个长期基准面半旋回。通过不同级次基准面旋回成因的沉积动力学分析和表征储层宏观非均质性的各项岩心化验、统计学数据定量分析,指出随着长期基准面的上升,各短期基准面旋回层内非均质性变强、各中期基准面旋回层间非均质性变弱、各短期基准面旋回平面非均质变强;随着长期基准面的下降,各变化趋势正好相反。指出基准面旋回及其伴随的可容纳空间变化所引起的沉积环境的变化是储层宏观非均质特征差异的决定因素。     

惠州凹陷古近系珠海组-恩平组高分辨率层序格架与储层分布规律

利用高分辨率层序地层学理论和技术方法,综合测井、地震和岩芯资料对惠州凹陷深层储层——珠海组和恩平组进行高分辨率层序地层学分析,从中识别出短期、中期、长期3个级别的基准面旋回层序,进一步分析短期旋回层序结构,划分出向上"变深"非对称型、向上变浅非对称型、对称型3种基本结构类型。依据等时地层对比法则并利用地震资料约束进行不同级次基准面旋回层序的联井对比,建立了珠海组和恩平组的等时地层格架,在等时地层格架内进行了单砂体的对比,并在等时地层格架内分析了储层的时空展布规律。     

高分辨率层序地层学在陆相地层研究中若干问题的讨论

高分辨率层序地层学在实际应用中尚存在若干值得注意的问题。理论上要深刻理解基准面概念的涵义,认识到基准面的相对性属性;注意区分地层记录中存在着自旋回和异旋回两种不同成因机制的沉积旋回。在基准面旋回的划分和识别上,原有的短期、中期和长期旋回三级划分方案在定义上过于含糊,易产生歧义,建议以多数学者比较认同的旋回时限进行五级划分为宜。在应用上,以相组合和相序特征为依据划分基准面旋回,避免以粒序特征为凭识别基准面旋回,结合实践提出陆相沉积环境中从冲积平原→深湖相的五级基准面旋回识别模式和实例。     

流水下切的动力学机制、物理侵蚀过程和影响因素:评述和展望

流水下切是指河流河道在基岩中的垂直切割。自20世纪90年代以来,由于对全球尺度的气候、地表过程和构造之间相互作用的认识,以及工程建设和天然资源管理决策的需要,流水下切成为构造地貌学的理论研究前缘。文章从动力学机制、物理侵蚀过程、三大外来变量构造、气候和基准面变化的影响,以及区分这些变量影响的可能性等方面,对流水下切研究的最新进展予以评述。未来流水下切研究要在流水动力学和地球动力学两方面探索更多的科学问题     

长期基准面旋回内河口坝构型的演化规律--以胜坨油田坨7断块沙二段下油组为例

综合应用高分辨率层序地层学理论和储层构型分析方法,以渤海湾盆地东营凹陷胜坨油田坨七断块沙二段下油组为例,研究长期基准面旋回背景下河口坝构型的演化规律。研究表明,研究区沙二段下油组对应一个长期基准面下降半旋回,并可进一步划分为8个中期基准面旋回及若干短期和超短期旋回。随着长期基准面的下降,河口坝越来越连片,坝体上分流河道的规模变大,延伸距离变长;在长期基准面下降早期,河口坝的侧向拼接样式以河口坝侧缘相互交错及河口坝之间被泥岩隔开样式居多,在长期基准面下降晚期,河口坝的侧向拼接样式主要为河口坝坝主体与侧缘的侧向叠置和河口坝侧缘与侧缘的侧向叠置;同时,随着长期基准面的下降,垂向上河口坝砂体间的连通性逐渐变好,河口坝前积的角度逐渐变小。长期基准面旋回对河口坝构型的控制主要通过可容空间的增减,沉积物供给速率的变化起作用。该研究对同类型油气田的砂体预测和剩余油分布的预测均具有重要的指导意义。     

Correlation methods of base-level cycle based on wavelet neural network

The authors discussed the method of wavelet neural network (WNN) for correlation of base-level cycle. A new vectored method of well log data was proposed. Through the training with the known data set, the WNN can remenber the cycle pattern characteristic of the well log curves. By the trained WNN to identify the cycle pattern in the vectored log data, the ocrrelation process among the well cycles was completed. The application indicates that it is highly efficient and reliable in base-level cycle correlation.     

Correlation methods based on wavelet of base-level cycle neural network

The authors discussed the method of wavelet neural network （WNN） for correlation of base-level cycle. A new vectored method of well log data was proposed. Through the training with the known data set, the WNN can remenber the cycle pattern characteristic of the well log curves. By the trained WNN to identify the cycle pattern in the vectored log data, the ocrrdation process among the well cycles was completed. The application indicates that it is highly efficient and reliable in base-level cycle correlation.     

From straight to deeply incised meandering channels: Slope impact on sinuosity of confined streams

Meandering channels and valleys are dominant landscape features on Earth. Their morphology and remnants potentially indicate past base-level fluctuations and changing regional slopes. The prevailing presence of meandering segments in low-slope areas somewhat confuses the physically based relationships between slope and channel meandering. This relationship underlies a fundamental debate: do incised sinuous channels actively develop during steepening of a regional slope, or do they inherit the planform of a preexisting sinuous channel through vertical incision? This question was previously explored through reconstructed evolution of meandering rivers, numerical simulations, and controlled, scaled-down laboratory experiments. Here, we study a rare, field-scale set of a dozen adjacent perennial channels, evolving in recent decades in a homogeneous erodible substrate in response to the Dead Sea level fall (> 30 m over 40 years). These channels are fed by perennial springs and have no drainage basin or previous fluvial history; they initiated straight and transformed into incising meandering channels following the emergence of the preexisting lake bathymetry, which resulted in increased channel lengths and regional slopes at different rates for each channel. This field setting allows testing the impact of changing regional slope on the sinuosity of a stream in the following cases: (a) relatively long and low-gradient shelf-like margins, (b) a sharp increase in the basinward gradient at the shelf-slope transition, and (c) gradually steepening slopes. Under a stable and low valley slope, the channels mainly incise vertically, inheriting a preexisting sinuous pattern. When the regional slope steepens, the channels start to meander, accompanying the vertical incision. The highest sinuosity evolved in the steepest channel, which also developed the deepest and widest valley. These results emphasize the amplifying impact of steepening regional slope on sinuosity. This holds when the flow is confined and chute cutoffs are scarce.     

基准面旋回与A/S比值的函数关系及地质意义

应用高分辨率层序地层学中的基准面旋回原理,对基准面变化进行了详细地分析。由于基准面的升降变化引起了可容纳空间与沉积物供给量的相对变化,相对应的可容纳空间变化率和沉积物供给率同时也发生变化,因而导致了在不同时期同一地区的地层在相序、保存程度和叠加样式上的差异,以及在同一时期内不同地区在相域上的差别。结合Cross提出的地层基准面原理以及沉积物供给量、可容纳空间变化率、沉积物供给率和沉积通量的物理属性,建立了相应的函数模型,推导说明了其函数关系式,阐述了它们之间的相互关系,总结了各自的变化规律和所代表的地质意义。本文的研究成果有助于进一步加深理解高分辨率地层层序的形成和演化,并且对于高分辨率地层层序的划分与对比,也有一定的借鉴意义。     

鄂尔多斯盆地中部延安地区中侏罗统延安组高分辨率层序地层研究

利用高分辨率层序地层学方法,以延水河剖面研究为重点,详细剖析了中侏罗统延安组不同级次基准面旋回划分,建立了鄂尔多斯盆地延安地区延安组高分辨率层序地层格架。共识别出了36个短期、8个中期和3个长期基准面旋回。讨论了不同级次基准面旋回叠加式样与沉积相、沉积作用和构造作用等的响应关系,进一步通过基准面旋回层序研究了盆地的充填演化史。