Carbonate Diagenesis

Over the years, many papers on carbonate diagenesis have been published in Sedimentology, the journal of the International Association of Sedimentologists. This volume presents a collection of these papers with a commentary. The emphasis of the book is on the diagenesis of shallow-marine carbonate sediments and the editors have chosen 12 papers which are reproduced in full. To widen the scope of this volume the abstracts for another 16 papers are presented. These provide further examples of diagenetic studies and help to extend the coverage of the book. The reprints and abstracts are divided into three groups, dealing with marine, meteoric and burial diagenesis respectively. Each collection is preceded by a commentary which briefly summarizes the topic and introduces the reprints and abstracts to come

The Nature of Carbonate Depositional Systems: Comparison of Carbonates and Siliciclastics. The Classification and Nature of Carbonate Porosity. Diagenetic Environments of Porosity Modification and Tools for their Recognition in the Geologic Record. Normal Marine Diagenetic Environments. Evaporative Marine Diagenetic Environments. Introduction to Diagenesis in the Meteoric Environment. Meteoric Diagenesis Environments. Dolomitization Associated with Meteoric and Mixed Meteoric and Marine Waters. Burial Diagenetic Environment. References. Index.

Carbonate Sediments and Their Diagenesis

Carbonate diagenesis is a subject of enormous complexity because of the basic chemical reactivity of carbonate minerals. These carbonate minerals react quickly with natural waters that either dissolve the carbonates, or precipitate new carbonates to bring the water into equilibrium with the host carbonate sediments and rocks. These rock-water interactions either create porosity by dissolution, or destroy porosity by the precipitation of carbonate cements into pore spaces. Carbonate Diagenesis and Porosity examines these important relationships in detail. This volume is published in co-operation with OGCI, and is based on training courses organised by OGCI and taught by Dr. Moore. It is intended to give the working geologist and university graduate student a reasonable overview of carbonate diagenesis and its influence on the evolution of carbonate porosity. It starts with a discussion of the major differences between carbonates and siliciclastics so that the novice will have an appreciation of the basic nature of the carbonate system. Carbonate porosity, its nature and its classification is then discussed so that the relationship between diagenesis and porosity can be established. Environments of diagenesis and their characteristics are outlined, stressing the nature of pore fluids found in each environment. Tools for the recognition of these environments are then discussed with stress on the constraints suffered by each technique. Each major diagenetic environment is then discussed in detail with petrographic, geochemical characteristics outlined, and an in depth discussion of the impact of the environment's diagenetic processes on porosity development and evolution. Diagenetic models are developed where appropriate and criteria for recognition listed. Case histories illustrating these concepts and models are presented for each major diagenetic environment and sub-environment. Over 160 line drawings illustrate the book. Petrographic characteristics of porosity and diagenetic fabrics and textures are illustrated using numerous photomicrographs taken specifically for the book by the author. The book has been extensively indexed, and includes a large, current reference section. This book should be useful to any geologist interested in, or working with, carbonate sediments and rocks. It will be particularly useful to the industrial geologist concerned with the exploration or exploitation of hydrocarbons from carbonate rock sequences where an understanding of porosity development, evolution, and prediction are important. In addition, this book will be a good text for advanced carbonate courses at graduate level, and an appropriate reference book for graduate students working in, or interested in, carbonate rock sequences and sediments.

Diagenesis research is the foundation of hydrocarbon reservoir characterization and exploration. Reactive transport modeling (RTM) is an emerging approach for diagenesis research, with unique capability of quantification and forward modeling of the coupled thermo-hydro-chemical processes of diagenesis. Using TOUGHREACT simulator, this thesis investigates the two most important fluid-rock interactions in carbonate rocks, i.e., dolomitization and karstification, based on generic model analyses and a case study in the Ordos Basin, China. In particular, this study attempts to quantitatively characterize the diagenetic processes and to reconstruct the diagenesis-porosity evolution of carbonate reservoirs. Some controversies in carbonate diagenesis research, which cannot be well explained by classical geological methods, have also been discussed. The results are helpful to better understand the spatial-temporal distribution and co-evolution of diagenesis-mineral-porosity during the complicated diagenetic processes with their potential controlling factors, and to reduce the uncertainty of reservoir quality prediction.

The 2nd Edition of Carbonate Reservoirs aims to educate graduate students and industry professionals on the complexities of porosity evolution in carbonate reservoirs. In the intervening 12 years since the first edition, there have been numerous studies of value published that need to be recognized and incorporated in the topics discussed. A chapter on the impact of global tectonics and biological evolution on the carbonate system has been added to emphasize the effects of global earth processes and the changing nature of life on earth through Phanerozoic time on all aspects of the carbonate system. The centerpiece of this chapter—and easily the most important synthesis of carbonate concepts developed since the 2001 edition—is the discussion of the CATT hypothesis, an integrated global database bringing together stratigraphy, tectonics, global climate, oceanic geochemistry, carbonate platform characteristics, and biologic evolution in a common time framework. Another new chapter concerns naturally fractured carbonates, a subject of increasing importance, given recent technological developments in 3D seismic, reservoir modeling, and reservoir production techniques. Detailed porosity classifications schemes for easy comparison Overview of the carbonate sedimentologic system Case studies to blend theory and practice

Diagenesis of carbonates and clastic sediments encompasses the biochemical, mechanical, and chemical changes that occur in sediments subsequent to deposition and prior to low-grade metamorphism. These parameters which, to a large extent, control diagenesis in carbonates and clastic sediments include primary composition of the sediments, depositional facies, pore water chemistry, burial–thermal and tectonic evolution of the basin, and paleo-climatic conditions. Diagenetic processes involve widespread chemical, mineralogical, and isotopic modifications affected by the original mineralogy of carbonate and clastic sediments. These diagenetic alterations will impose a major control on porosity and permeability and hence on hydrocarbon reservoirs, water aquifers, and the presence of other important economic minerals. In this Special Issue, we have submissions focusing on understanding the interplay between the mineralogical and chemical changes in carbonates and clastic sediments and the diagenetic processes, fluid flow, tectonics, and mineral reactions at variable scales and environments from a verity of sedimentary basins. Quantitative analyses of diagenetic reactions in these sediments using a variety of techniques are essential for understanding the pathways of these reactions in different diagenetic environments.

The present volume is an intellectual agglomeration covering a variety of topics in diagenesis. It starts with the diagenesis of marine pore waters and soft-sediment deformations, followed by two chapters on sandstones - one on climatic influence in terrestrial sandstone diagenesis and the other on the deep-sea volcaniclastic sandstones. Diagenesis of carbonates is treated next, with one chapter on compactional diagenesis and another devoted to a case study (Aymestry Limestone Beds, UK). There are two chapters on the origin and migration of oil: (a) maturation of organic matter, and (b) relation of diagenesis to mineralization and hydrocarbon reservoir development, followed by a chapter on sedimentary ore genesis - banded iron-formation. In conclusion there are two chapters on paleosols. This book will be of interest to geologists, geochemists and petroleum engineers.