Study of Modern Gravelly Braided River Deposits with Special Reference to Spatial Variations in Porosity and Permeability

现代砾石辫状河沉积物的研究，特别考虑孔隙度和渗透率的空间变化

• 批准号: 9902894
• 负责人: John Bridge
• 金额: $ 30.01万
• 依托单位: SUNY at Binghamton
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9902894&HistoricalAwards=false
• 关键词: Study; Modern; Gravelly; Braided; River

9902894BridgeThe nature and origin of gravelly braided-river deposits will be studied, with specific emphasis on spatial variations in porosity and permeability. Channel-belt deposits will be studied in 3-D using closely spaced ground-penetrating radar profiles tied to trenches, cores and wireline logs. An innovative aspect of this study is that the river and sediment will be frozen during some of the sampling (being on the North Slope of Alaska), thus minimizing disturbance during coring, and enabling easy access to all parts of the channel belt. This sampling strategy will allow description of the 3-D variation of the different types and scales of stratification, grain-size distributions, porosity and permeability, and related geophysical properties of the deposits. Particular attention will be paid to zones of high permeability (open-framework gravels) and low permeability (muds). Interpretation of these patterns of deposition will be attempted using: (1) knowledge of the mode of channel cutting, migration and filling, obtainable from sequential aerial photographs, and; (2) inferences about the geometry, sediment textures and bed forms of the channel bed during major erosional-depositional events. An ultimate objective is construction of a detailed, 3-D depositional model for gravelly braided rivers that is a major improvement over existing models, particularly in the description of the large-scale stratification patterns. Also, prediction of porosity and permeability in relation to sedimentary facies is important for modeling of fluid flow through aquifers and hydrocarbon reservoirs in analogous ancient deposits. However, there is a critical lack of poroperm data from gravelly braided rivers to support such modeling. The results of a pilot study indicate that the objectives of this project can be realized.

9902894桥砾石辫状河沉积的性质和起源将进行研究，特别强调孔隙度和渗透率的空间变化。将利用与沟槽、岩心和电缆测井相联系的密集的探地雷达剖面图，以三维方式研究带状矿床。这项研究的一个创新方面是，河流和沉积物将在一些采样期间冻结（在阿拉斯加北坡），从而最大限度地减少了取芯期间的干扰，并使通道带的所有部分都易于进入。这一取样战略将能够描述矿床不同类型和层次、粒度分布、孔隙度和渗透率以及相关地球物理特性的三维变化。将特别注意高渗透性（开放式骨架砾石）和低渗透性（泥浆）区域。这些沉积模式的解释将尝试使用：（1）知识的渠道切割，迁移和填充的模式，可从连续的航空照片，和（2）的几何形状，沉积物结构和河床的形式在主要的侵蚀-沉积事件的推断。一个最终的目标是建设一个详细的，3-D的砾石辫状河的沉积模型，这是一个重大的改进现有的模型，特别是在大规模的分层模式的描述。此外，与沉积相相关的孔隙度和渗透率预测对于模拟类似古代沉积物中含水层和碳氢化合物储层的流体流动非常重要。然而，有一个关键缺乏poroperm数据砾石编织河流，以支持这样的建模。试点研究的结果表明，该项目的目标能够实现。