Sedimentological Characterization of Carbonate Rocks
More than 60% of the world’s oil and 40% of the world’s gas reserves are held within carbonate rocks. An understanding of these will ultimately help improve sedimentological facies and reservoir quality prediction while reducing uncertainties with respect to reserve estimates and potential oil/gas recovery. The first part of this course provides an understanding of the fundamentals of carbonate sedimentology, together with the skills required to characterize and interpret carbonate rocks, in order to establish an understanding of their depositional environment and implications for reservoir geometry and extents. In detail, the course offers an insight into the environmental, biological, physical, chemical and climatic controls on the carbonate factory, enabling facies analysis. In addition, sequence stratigraphical methods and their application will be covered in the second part of the course to provide all the tools needed to reconstruct the sedimentological architecture at the field scale. These factors help reduce uncertainties associated with the prediction of geometries and lateral heterogeneity within carbonate reservoirs.
Part A: in order to appreciate the evolution and development of carbonate sediments, a basic understanding of the chemical, biological and physical processes involved in their formation is essential. The first part of this course outlines the controls on carbonate production (the carbonate factory), and the impact of carbonate producers on carbonate accumulation and hence implications for carbonate body geometries. It considers the key textural (Dunham classification), mineralogical, compositional and fabric/sedimentary structure observations necessary to help evaluate and interpret carbonate rocks. Carbonate deposition is controlled by a wide range of internal and external factors, including the light, temperature, energy levels, salinity and nutrient availability. Understanding these factors provides a better perspective on the nature and distribution of carbonate sediments, and thus, enhances reservoir description and the subsequent construction of more robust depositional models. The effects of the environmental controls on carbonate production, wherever possible, will be illustrated with observations from modern day analogues.
Part B: To fully understand carbonate systems, it is necessary to appreciate the larger scale depositional settings within which they develop. An understanding of the tectonic setting and the depositional geometry of a carbonate platform is vital in developing accurate depositional models. These aspects, together with the types of carbonate accumulations and their applications, will be fully addressed in this course. Finally, the principles of sequence stratigraphy, its importance in subsurface carbonate reservoir characterisation and the tools and techniques required for the application of sequence stratigraphy will all be covered. Overall, these factors aid in the prediction of the sedimentological heterogeneity expected at the large-scale, and hence, the interpretation of the reservoir architecture.
Upon completion of the course, participants will have:
- A good understanding of a carbonate system, including the major controls on carbonate production;
- An appreciation of the heterogeneous nature of carbonate sediments and how this may impact predictability variations within the subsurface;
- An understanding of the techniques used to apply a sequence stratigraphic framework in a typical carbonate succession, and hence the impact on reservoir quality prediction.
The course will be organised into two sessions:
Part A: The carbonate system - “Carbonates are born not made”
- The mineralogy of carbonates;
- The composition of carbonate rocks: skeletal vs non-skeletal allochems;
- Classification of carbonate rocks;
- The controls on carbonate production;
- The carbonate factory - the impact of carbonate producers on the carbonate accumulation geometry;
- Types of carbonate accumulations;
- Applied carbonate facies analysis;
- Typical carbonate facies observed in core and thin-sections;
- The key to identifying carbonate depositional environments.
Part B: Sequence stratigraphy applied to carbonate reservoirs
- Introduction to the basic concepts of sequence stratigraphy;
- Carbonate record and sea level;
- Methods used to establish a sequence stratigraphic framework;
- Prediction of the sedimentological heterogeneity and interpretation of the sedimentological reservoir architecture.
Each section will be accompanied by example case histories and exercises.
This course is designed for petroleum geologists, geoscientists, petrophysicists and engineers involved in exploration and production of carbonate plays.
Although previous knowledge on carbonate sedimentology is not necessarily required, participants should have some knowledge of geology.
About the Instructor
Laura Galluccio (Ph.D) is one of Badley Ashton’s UK-based senior carbonate reservoir geologists with an interest in carbonate petrography and sedimentology. She specialises in sedimentology, diagenesis and reservoir quality characterization of limestones and dolomites in both conventional and unconventional reservoirs. She has wide experience in the Middle East, the USA, Europe and Africa. The projects she has been involved in cover a wide range of depositional environments from shallow to deeper water carbonates. Laura received his BSc, MSc and PhD at the University of Naples (Italy), with her PhD conducted in conjunction with Shell Italy. As an effective communicator and with a proven track record of excellent client care, past roles include Team Leader of the Carbonate Group, and local Business Manager and Consultant Geologist based in PDO’s offices, Muscat. Since her appointment as Regional Manager in August 2017, Laura oversees business activity in the Middle East, Africa and Asia, supported by regional Operations and Portfolio Managers. Laura’s other research interests include sedimentology and sequence stratigraphy of ancient and recent carbonate platforms and the characterization of diagenetic processes affecting carbonate sediments with integration into the regional framework and influence on the pore system. She is currently involved in research on the diagenesis and pore volume assessment of Hyamm Formation in Oman in collaboration with the Ferrara University and Sultan Quaboos University, as well as a project focused on the role of hydrocarbons emplacement for calcite precipitation, in collaboration with Newcastle University. Laura has undertaken teaching of geological mapping, petroleum geology and reservoir quality evaluation at both BSc and MSc levels, while co-supervising a variety of BSc and MSc carbonate research projects.
Catherine Breislin (Ph.D) is a Reservoir Geologist working in Badley Ashton’s UK-based Carbonate Team. She specialises in carbonate sedimentology, diagenesis and reservoir quality analysis using a range of techniques in both conventional and unconventional reservoirs. Her work to date has focused on investigating the controls of depositional facies, platform architecture, and structural development on basin-scale diagenetic fluid flow and its impact on reservoir quality. Her project work has covered a wide range of depositional environments from shallow to deeper water carbonates.
Catherine received her MESci at the University of Liverpool (UK), and PhD at the University of Manchester (UK), with her PhD conducted in conjunction with Shell and the British Geological Survey. Catherine has a strong background in field geology, core-logging, carbonate sedimentology and geochemistry, and is proficient in conducting spatial integration of multiple data sets. She also has experience in lab-based mineral identification analyses, where she has developed best practice methodologies and workflows. While co-supervising an MSc carbonate research project at Manchester University, Catherine has undertaken teaching of carbonate sedimentology, geological mapping, petroleum geology and reservoir quality evaluation at both BSc and MSc levels.