Depositional Processes and Reservoir Characteristics of Siltstones, Mudstones and Shales
Erik Scott, Arnold H. Bouma, 2004. "Depositional Processes and Reservoir Characteristics of Siltstones, Mudstones and Shales", Depositional Processes and Reservoir Characteristics of Siltstones, Mudstones and Shales, Erik D. Scott, Arnold H. Bouma
Download citation file:
Siltstones, mudstones and shales have been studied mainly with regard to general transport-deposition processes and clay mineralogy. A small group of investigators, with differing backgrounds, have worked on these fine-grained deposits. While there have been a number of resulting publications, they are spread out over a wide array of geological literature.
Recent studies on deepwater deposits from cores and outcrops indicate that the presence of finer-grained deposits greatly affect the fluid flow properties of deepwater reservoirs. Further analysis indicates that the majority of these finer-grained deposits have a large silt component and are closer to siltstones rather than mudstones, commonly called shales. Studies on these deposits have indicated that they are often comprised of graded fine silt laminae sandwiched between films of clay minerals, quartz dust and organics. Characteristics and rock properties of these deposits, which resulted from a variety of depositional processes, are just beginning to be understood. Depending on the transport-deposition processes, the architecture of the deposit will have different 3D extents and continuity as well as varying rock properties.
Stratigraphic prediction of the position and dimensions of the fine-grained beds can indicate whether the deposits will be a barrier or a baffle to fluid flow or a possible reservoir for natural gas. Minor variations in depositional style and other characteristics can result in more differences than presently assumed.