Diagenesis is an essential aspect, although quite different in processes and effects, of mudrocks, sandstones, and carbonate rocks. Pdf diagenesis and reservoir properties of the permian ecca. The multifarious processes that come under the term diagenesis are chemical, physical, and biological. Purchase of an open document does not constitute license for republication in any form, nor does it allow web posting without prior written permission. Later diagenetic patterns cross facies boundaries and depend on regional fluid migration patterns stonecipher and may, 1992. Composition affects sandstone diagenesis in two ways. Learn vocabulary, terms, and more with flashcards, games, and other study tools.
Combines key papers in sandstone diagenesis published in sedimentology over the last 30 years. Papers were chosen with the aim of giving readers who are unfamiliar with the field of diagenesis a quick primer on basic concepts that are widely applied today in reservoir quality assessment. Diagenesis is considered a relatively lowpressure, lowtemperature alteration process, whereas metamorphism is considered to be a rockalteration process occurring at relatively higher pressures and temperatures. Records the development of diagenesis from the description of grain shapes through provenance, petrography and analytical geochemistry to predictive models of diagenetic process. Pdf diagenesis comprises a broad spectrum of physical, chemical and biological postdepositional processes by which original sedimentary. Diagenesis and reservoir quality of the upper mississippian.
Diagenetic origin of graywacke matrix minerals pages. Dapples department of geoiogy, northwestern university, evanston, in. Based on thin sections, scanning electron microscopy sem, xray diffraction xrd image analysis and cathodoluminescence cl, a comprehensive analysis of the sedimentology, petrography. We compare clay diagenesis in early calcitecemented sandstones with sandstones in which the calcite ce ment was absent during burial diagenesis. Despite the fact that published data gives a vast amount of information on the geology, sedimentology, and lithostratigraphy of the ecca group in the karoo basin of south africa, little is known about the diagenesis of the potentially feasible or economically viable sandstones and mudrocks of the ecca group. Sandstone diagenesis and reservoir quality prediction. For clay mineral investigation, the sandstone diagenesis published in sedimentology over the last 30 years. Variations in the distribution of diagenetic alterations usually accentuate the variations in depositional porosity and permeability. Diagenesis consists of the physical, chemical, andor biological changes that alter sediments during lithification. Impacts of diagenesis on reservoir quality in a sedimentary. Jun 01, 2017 the deep hightemperature, highpressure lower cretaceous bashijiqike sandstone buried to depths as great as 6. This study aims to provide an account of the diagenesis of sandstones and mudstones from the ecca group. As the rock is carried deeper by further deposition above, its organic content is transformed into kerogens and bitumens. Not all of these are equally supported by quantitative data, observations, and rigorous hypothesis testing.
Effectively predicting sandstone quality depends on predicting diagenetic history as a product of depositional environments, sediment. Sandstone porosity lossa big picture view of the importance of compaction. In the early stages, this transformation of sediment into sedimentary rock, is accompanied simply by a reduction in porosity, while its component mineralogy remains unaltered. Sandstone diagenesis wiley online books wiley online library. Within compacting mudstone sequences several depth zones can be recognised in which distinctive diagenetic reactions take place. Most striking are those involving carbonate precipitation or replacement. Deep burial diagenesis and reservoir quality evolution of. Diagenesis and reservoir quality of the upper mississippian aux vases sandstone, illinois basin by janet k. In this lesson we will look at the various diagenetic processes at work. An important diagenetic alteration which is recognized to be instituted immediately following deposition of a sedimentary layer involves oxidation or reduction. The evolution of sand to stone, in burley sd and worden rh eds. Sandstone diagenesis of the neogene surma group from the. Diagenesis and its effect on reservoir quality of silurian sandstones, tabei area, tarim basin, china vol.
Diagenesis is a process by which the sediments and the existing sedimentary rocks undergo physical and chemical change by compaction, cementation, etc. Petrography and diagenesis of the hosston sandstone reservoirs at bassfield, jefferson davis county, mississippi. Issuu is a digital publishing platform that makes it simple to publish magazines, catalogs, newspapers, books, and more online. The diagenetic evolution of these sandstones caused severe deformation in pore space and grain morphology during deposition and burial. The objectives of the study proposed herein are i to give a better insight of the hutton sandstone by compiling, classifying and. Pdf sandstone diagenesis and reservoir quality prediction. With the maturation of organic matter, some locations were charged with some oil and gas. Early diagenetic patterns correlate with environment of deposition and sediment composition.
Possible links between sandstone diagenesis and depthrelated. Sandstone diagenesis journal of the geological society. Diagenesis does not include changes that occur as a result of weathering. Sandstone modal composition was determined from all thin sections of medium to coarsegrained sandstones by counting 300 points per thin section. They include compaction, deformation, dissolution, cementation. Diagenesis affects all sediments after their deposition and includes a fundamental suite of physical, chemical and biological processes that control the texture, mineralogy and fluidflow properties of sedimentary rocks. Chapter 2 sandstone diagenesis in relation to preservation, destruction and creation of porosity. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Petrology, diagenesis, and sedimentology of oil reservoirs in upper cretaceous shannon sandstone beds, powder river basin, wyoming by paula l hansley and c. Petrology, diagenesis, and sedimentology of oil reservoirs in. Diagenesis comprises a broad spectrum of phys ical, chemical and biological postdepositional processes by which original sedimentary assemblages and. Dduring the early to middle diagenesis stages, carbonate cements filled the pores, and feldspar overgrowth appeared. Diagenesis is the process that describes physical and chemical changes in sediments caused by increasing temperature and pressure as they get buried in the earths crust.
Unlimited viewing of the articlechapter pdf and any associated supplements and figures. A comprehensive analysis of the sedimentology, petrography. The higher the quartz content, the greater the mechanical stability less compaction occurs. On 9 march 1977, the symposium on sandstone diagenesis organised jointly by the geological society of london, the petroleum exploration society of great britain, and the british sedimentological research group, drew an audience too large to assemble in the geological societys own lecture theatre.
Easily share your publications and get them in front of issuus. Diagenesis is one of the most important factors that affects reservoir rock property. Diagenesis is the name for a wide range of changes that affect sediments during their progress to become sedimentary rocks. The principal diagenetic minerals in the surma group sandstones are quartz overgrowths, fecarbonates mainly fecalcite and authigenic. The limit between diagenesis and metamorphism is not precise in terms of pressure or temperature, nor is there a sharp boundary between diagenesis and weathering. Oct 15, 2018 the sandstone from the oligocene xiaganchaigou formation e3 in the lengdong area, qaidam basin, china, is extensively distributed and acts as an effective regional reservoir for hydrocarbon accumulation. Bassfield field, discovered in 1974, is a gas accumulation in lower cretaceous hosston formation sandstone reservoirs above a deepseated salt structure. Chapter 2 diagenesis of sandstones the coarseness of grain. Reservoir quality is a critical risk factor in the development of these ultradeep reservoirs. The higher the variety of minerals, the lower the chemical stability more cementation or dissolution occurs. Effect of alkaline diagenesis on sandstone reservoir quality. The major carbon source is organic matter which is degraded by various microbiological and inorganic reactions to bicarbonate as one product. Later diagenetic patterns cross facies boundaries and depend on regional fluid migration patterns stonecipher and may.
Diagenesis of sedimentary rocks, characteristics of sedimentary. This chapter concerns the diagenetic modification of sands following deposition, such modifications occurring as progressive stages. Dissolutionprecipitation mechanisms for diagenesis in. Pdf the impact of diagenesis on the heterogeneity of. A b s t r a c t diagenesis exerts a strong control on the quality and heterogeneity of most clastic reservoirs.
An example of diagenesis is the chemical alteration of a feldspar to form a distinctly new mineral in its place, a clay mineral. Wileyblackwell publishing, international association of sedimentologists reprint series, vol. Diagenesis alters the original pore type and geometry of a sandstone and therefore controls its ultimate porosity and permeability. The purpose of this paper is to describe clay diagenesis in a sandstone reservoir of the brent group in the north sea that is heterogeneously cemented by calcite. Whitney a multidisciplinary approach to research studies of sedimentary rocks and their constituents and the evolution of sedimentary basins both ancient and modern. Summary this chapter concerns the diagenetic modification of sands following deposition, such modifications occurring as progressive stages. In its broadest sense, diagenesis encompasses all natural changes in sediments occurring from the moment of deposition, continuing through compaction, lithification and beyondstopping short of the onset of metamorphism. The impact of diagenesis on the heterogeneity of sandstone reservoirs. Cduring the early diagenesis stage, quartz overgrowth developed. Diagenesis comprises a broad spectrum of physical, chemical and biological postdepositional processes by which original sedimentary assemblages and their interstitial pore waters react in an attempt to reach textural and geo chemical equilibrium with their environment curtis. Thus, the nebulous domain of diagenesis lies somewhere between the illdefined borders of weathering at its shallow end and lowgrade metamorphism at its deep end. Pdf diagenesis and reservoir quality semantic scholar.
Petrography and diagenesis of a halfbillionyearold cratonic sandstone. Diagenesis and its effect on reservoir quality of silurian. Pitman,1 mitchell henry,1 and hannes leetaru2 abstract the aux vases sandstone upper mississippian is exten sively cored in the illinois basin and thus offers the opportunity. Cementation is the diagenetic process by which authigenic minerals are precipitated in the pore space of sediments which thereby become lithified. We show how such a realistic model of diagenesis can be included in a compactive model of the sedimentpore water system, and by using the limit of weak solubility also known as solid density asymptotics, we show how an.
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