Clay mineral diagenesis and quartz cementation in mudstones: The effects of smectite to illite reaction on rock properties   总被引：1，自引：0，他引：1  

Christer Peltonen  Øyvind MarcussenKnut Bjørlykke  Jens Jahren 《Marine and Petroleum Geology》2009

The Late Cretaceous to Early Tertiary sequence of the Vøring and Møre Basins from the Norwegian Sea has been examined with respect to mineralogy based on 319 cutting samples from five wells. A clear relationship between mineralogy and well log data is demonstrated. A significant change with respect to velocity, porosity and density occurs within the depth interval corresponding to 80–90 °C. At shallow depths/temperatures (<2.0 km/70 °C), compaction is mainly mechanical and the physical properties are similar to what has been measured by experimental compaction of mudstones. At greater depths, however, the log derived velocities and densities are higher than those produced by experimental compaction indicating significant chemical compaction. XRD analyses show a progressive alteration of smectite to illite (S–I) within this depth/temperature interval which results in the release of significant amounts of silica into solution. Detrital silt and fine-grained quartz showed no secondary quartz overgrowths. These grains are isolated within a clay matrix and surrounded by clay minerals, thus limiting the available surface area and pore space for quartz overgrowths. Chemical analyses (XRF) indicate that silica is conserved within this depth interval, and the amount released from S–I alteration was locally precipitated. Field emission gun-scanning electron microscopy (FEG-SEM) and cathode luminescence (CL) identified authigenic micro-crystalline quartz cement within the clay matrix at temperatures above ∼85 °C. This is accompanied by an increase in velocity and density indicating that the S–I reaction and the precipitation of authigenic quartz caused a significant change in the rock stiffness.  相似文献   

水泥搅拌桩快—慢静荷载法承载力对比试验回归分析     

程俊贤  黄文通 《浙江国土资源》2000,(1)

水泥搅拌桩快速荷载法与慢速荷载维持法对比试验回归分析的数学模型 ,目前尚未有文献专门报导。该文通过多组同一桩上的单桩和单桩复合地基承载力的快、慢荷载法对比试验 ,应用数学回归分析方法 ,建立数学模型 ,使快速法取代慢速法荷载试验成为可能。且在工程实践中已取得明显的效果  相似文献   

Systematic sequence-scale controls on carbonate cementation in a siliciclastic sedimentary basin: Examples from Upper Cretaceous shallow marine deposits of Utah and Coloradao,USA     

Kevin G. Taylor  Philip G. Machent 《Marine and Petroleum Geology》2010

Whilst the relationship between stratigraphic development and carbonate cementation within siliciclastic succession has been documented through a number case studies, these studies have been generally restricted to observations upon individual sequences and/or limited sub-surface data. In this paper, long-term (5 million years), large-scale (>200 km) stratigraphic controls on carbonate cementation patterns are documented from the Upper Cretaceous Panther Tongue Member, Blackhawk Formation and Castlegate Sandstone exposed in the Book Cliffs in Utah and Colorado, USA. Together, these comprise eight progradational wedges of sandstones, which interfinger with the Mancos Shale, deposited within the Western Interior Seaway foreland basin. Petrographic analyses of ferroan dolomite cement bodies within these sandstone wedges show that the ferroan dolomite cements are all early, relative to burial diagenesis within the host sandstones. Stable isotope analyses indicates that a significant meteoric component was present in precipitating fluids and this is consistent with the observation that cements, are always present down-dip of sequence boundaries and/or leached whitecaps beneath coals. In addition, the lateral distribution of cement bodies increases consistently up-succession from less than 5 km in extent in the older sequences, to 30 km in extent in the youngest sequences. These changes in distribution are in response to the increased progradation and increased and more aerially extensive sequence-boundary development in younger sequences. The implications of these data are that whilst localized spatial patterns of diagenesis, and in particular carbonate cementation, are predictable and controlled by the nature and presence of individual stratal surfaces, systematic diagenetic alteration patterns are also present at the sedimentary basin scale and controlled by the nature of larger-scale stratigraphic development and basin evolution. This evolution may be driven by eustatic shifts, or through tectonic or climatic driven base-level shifts. These observations allow an improved insight into the basin-scale processes that control the macroscopic diagenetic properties of sedimentary successions and sub-surface hydrocarbon reservoirs.  相似文献   

Quartz cementation in Late Cretaceous mudstones,northern North Sea: Changes in rock properties due to dissolution of smectite and precipitation of micro-quartz crystals     

Brit Thyberg  Jens JahrenTurid Winje  Knut BjørlykkeJan Inge Faleide  Øyvind Marcussen 《Marine and Petroleum Geology》2010

Late Cretaceous mudstones from two wells located in the northern North Sea and the Norwegian Sea have been examined with respect to quartz cement. Two different types of quartz cement (Type 1 and Type 2) have been identified using SEM/EDS/CL-analysis of drill-bit cuttings at depths 2370–2670 m (80–85 °C). Type 1 appears as relatively large aggregates (30–100 μm) of depth/temperature related crypto- or microcrystalline to macrocrystalline irregular quartz cement formed by local re-crystallization of biogenic silica. The CL-responses of Type 1 quartz cement give a clear indication of an authigenic origin. Type 2 quartz cement represents relatively high amounts of extremely fine-grained micro-sized (1–3 μm) crystals embedded as discrete, short chains or small clusters/nests within the illitized clay matrix. The CL-responses of micro-quartz crystals indicate an authigenic origin. The micro-quartz is most probably sourced from silica released during the smectite to illite dissolution–precipitation reaction. The petrographic evidence indicates that most of the silica released by the smectite to illite reaction has not been exported out of the mudstones. The silica released produce a subtle inter-connected micro-quartz network interlocked with aggregates of micro-quartz and authigenic clay crystals. This micro-quartz cementation process causes a significant and sharp change in the mudstone stiffness at the onset of the chemical compaction regime. This is indicated by an abrupt increase in well log velocity (Vp) and change in seismic facies close to 2500 m (80/85 °C).  相似文献   

外掺Cl对磷酸镁水泥离子溶出和孔结构的影响          下载免费PDF全文

董飞  周永全  董金美  文静 《盐湖研究》2021,29(2):20-28

通过测试不同Cl-(NaCl)掺量磷酸镁水泥(MPC)浸取液中离子浓度及MPC硬化体的孔结构和吸水率,研究了Cl-掺量和浸取时间对MPC硬化体平均孔径、孔隙率、孔径分布、孔体积分布、吸水率、MPC浸取液中Cl-、Na+、OH-、Mg2+、PO43-和K+浓度的影响,结果表明外掺Cl-对MPC孔结构、离子溶出及吸水率有显...  相似文献   

氯氧镁胶凝材料中总氯离子的测定:(Ⅱ)分析方法的比较与评价          下载免费PDF全文

李颖  余红发  董金美  王梅娟 《盐湖研究》2011,19(4):38-42

氯氧镁胶凝材料中的总Cl-含量是衡量产品吸潮、返卤和泛霜性能的关键指标之一。分别用重量法、CNS14164方法以及用甘油保护沉淀和过滤分离沉淀的Volhard法测定了5个MOC样品中的总Cl-含量;并以重量法的测定结果为基准,比较和评价了其余3种分析方法。结果表明,CNS 14164方法主要由沉淀转化引起负误差,该方法受随机误差的影响较大;用甘油保护沉淀后,测定的精密度和准确度提高,测定结果的相对误差为-0.24%,该方法可替代CNS14164方法;过滤分离沉淀后,分析结果受随机误差的影响较小,但该方法存在较大的系统误差,测定结果的相对误差为1.43%。  相似文献