Basin Evaluation and application of various petrophysical logs and interpretation

This powerpoint presentation provides infrormation on application of various petrophysical logs in evaluation and interpretation of sedimentary basins along with their combination



Rabindra Kunwar
[email protected]
KTM,Nepal

1. BASIN ANALYSIS

2. Application of log data in basin evaluation : Petrophysical logs, Borehole logging, log combinations for effective interpretation Submitted by Rabindra Kunwar (7921020) 3 rd Semester Central Department of Geology Submitted To Dr.Narsh Kazi Tamrakar Associate Professor Central Department of Geology

3. TABLE OF CONTENT

4. TABLE OF CONTENT TABLE OF CONTENT

5. TABLE OF CONTENT TABLE OF CONTENT

6. TABLE OF CONTENT 1 BASIN EVALUATION TABLE OF CONTENT 1 BASIN EVALUATION

7. TABLE OF CONTENT 1 BASIN EVALUATION APPLICATION OF BASIN EVALUATION 2 TABLE OF CONTENT 1 BASIN EVALUATION 2 APPLICATION OF BASIN EVALUATION

8. TABLE OF CONTENT 1 BASIN EVALUATION APPLICATION OF BASIN EVALUATION 2 VARIOUS PETROLOGICAL LOGS 3 TABLE OF CONTENT 1 BASIN EVALUATION 2 APPLICATION OF BASIN EVALUATION 3 VARIOUS PETROLOGICAL LOGS

9. TABLE OF CONTENT 1 BASIN EVALUATION APPLICATION OF BASIN EVALUATION 2 VARIOUS PETROLOGICAL LOGS 3 TABLE OF CONTENT 1 BASIN EVALUATION 2 APPLICATION OF BASIN EVALUATION 4 COMBINATION LOGS 3 VARIOUS PETROLOGICAL LOGS 4 COMBINATION LOGS

10. Basin Evaluation/Analysis Basin evaluation is a critical process in geology, geophysics, and hydrogeology that involves analyzing sedimentary basins to understand their formation, evolution, and potential for containing natural resources such as oil, gas, and minerals. Here are the key components and steps typically involved in basin evaluation: 1. Geological Setting Tectonic Setting: Determining the tectonic environment in which the basin formed (e.g., rift, foreland, intracratonic ). Stratigraphy: Analyzing the sequence of rock layers to understand their deposition over time. Structural Geology: Identifying faults, folds, and other structural features that influence the basin's architecture. 2. Basin Architecture Sedimentology: Studying the types of sediments, their source, and depositional environments. Paleogeography: Reconstructing past geographical settings and environments. Sequence Stratigraphy: Dividing the sedimentary sequence into genetically related units bounded by unconformities.

11. Applications of Basin Analysis Basin analysis has a wide range of applications across various fields. Here are some of the primary applications: 1. Hydrocarbon Exploration and Production Oil and Gas Exploration: Identifying and evaluating potential oil and gas reserves within sedimentary basins. Reservoir Characterization: Understanding the properties of rock formations that store hydrocarbons to optimize extraction. Enhanced Oil Recovery: Designing strategies for increasing the amount of extractable oil and gas. Elements and processes of a petroleum system

12. Mineral Exploration Economic Geology: Locating and assessing mineral deposits, such as coal, phosphates, and metallic ores. Strategic Minerals: Identifying basins rich in critical minerals essential for modern technology and industry. The Neuquen Basin is located in central Argentina.

13. Carbon Sequestration CO2 Storage: Identifying suitable geological formations for the storage of carbon dioxide to mitigate climate change. Monitoring and Verification: Ensuring the safety and effectiveness of CO2 sequestration sites.

14. Water Resource Management Aquifer Characterization: Studying the properties and extent of aquifers for groundwater extraction and management. Sustainable Water Use: Evaluating recharge rates and sustainable extraction limits for groundwater resources. Pollution Tracking: Understanding the flow of contaminants in groundwater systems within sedimentary basins. Remediation Planning: Designing strategies to clean up contaminated groundwater resources.

15. Geothermal Energy Resource Assessment: Identifying and characterizing geothermal reservoirs for energy production. Development Planning: Designing efficient extraction systems for geothermal energy. Implications of Spatial Variability in Heat Flow for Geothermal Resource Evaluation in Large Foreland Basins: The Case of the Western Canada Sedimentary Basin(Simon Weides,Jacek Majorowicz,2014)

16. Environmental and Geohazard Assessment Environmental Impact Studies: Assessing the potential environmental impacts of resource extraction and other basin activities. Geohazard Evaluation: Identifying risks such as earthquakes, landslides, and subsidence related to basin structures.

17. Urban Planning and Civil Engineering Selection: Evaluating the suitability of areas for infrastructure development, considering geological and hydrogeological factors. Risk Mitigation: Identifying and mitigating risks associated with ground stability and geohazards for construction projects.

18. Paleoclimatology and Paleoenvironmental Studies Climate Reconstruction: Using sedimentary records to reconstruct past climate conditions and environmental changes. Biodiversity Studies: Understanding the evolution and distribution of ancient ecosystems.

19. Waste Disposal Management Basin analysis helps assess the suitability of a basin for safe and secure disposal of waste materials. This can include low-level radioactive waste or industrial waste products. Factors like geological stability, potential for contamination migration, and long-term environmental impact are evaluated. Use of Basin Evaluation in Waste Disposal Mangement Geologic environments for nuclear waste repositories(Evan Paleologos , Abdel-Mohsen Mohamed,Kosmos Pavlopoulos,2017)

20. Geological Research: Advancing the understanding of sedimentary processes, basin evolution, and Earth's history. Marine Geology: Understanding sedimentary processes and resource potential in offshore basins. Coastal Management: Studying sediment dynamics and coastal erosion for sustainable coastal development.

21. Application of Log Data in Basin Evaluation Log data plays a crucial role in the evaluation of sedimentary basins, providing critical insights into the geological formations, reservoir characteristics, and hydrocarbon potential. Various types of logs are employed to gather information about the subsurface, each offering unique perspectives on the basin's geological makeup and resource potential.

22. Also known as well logging, is a process used to record detailed information about the geological formations penetrated by a borehole. This information is crucial for various applications in the oil and gas industry, hydrogeology, mining, and environmental science. Borehole logging Applications Hydrocarbon Exploration and Production Groundwater Exploration Mining Geotechnical Engineering Environmental Monitoring Borehole Logging

23. Gamma Logs Gamma ray logs measure the natural radioactivity of formations, primarily due to the presence of radioactive isotopes like potassium, uranium, and thorium. They are essential in identifying and correlating different lithologies, particularly between shales and sandstones. High gamma ray readings often correspond to shale layers, while lower readings indicate the presence of clean sandstones. This information is vital in understanding the stratigraphy, identifying potential source rocks, and evaluating the overall quality of reservoir rocks. Applications Stratigraphic correlation Source rock identification Shale content determination Lithology identification Advantages Reliable and widely used Provides information on the overall composition of the formation Relatively inexpensive Can be acquired in various logging environments Limitations Sensitivity to variations in mineralogy Can be influenced by borehole conditions Limited information on porosity and permeability

24. Gamma-ray logging Sonic logging

25. Resistivity Logs Resistivity logs measure the resistance of the formation to the flow of electric current. They are crucial in determining the presence of hydrocarbons and evaluating reservoir quality. Low resistivity values generally indicate the presence of conductive fluids like water or hydrocarbons, while high resistivity values suggest the presence of non-conductive formations like shales or carbonates. 1 Reservoir characterization Resistivity logs help in identifying and delineating reservoir layers, distinguishing between water-saturated and hydrocarbon-saturated zones. 2 Hydrocarbon saturation determination By comparing resistivity measurements with other log data, such as porosity logs, the saturation of hydrocarbons in the reservoir can be estimated. 3 Fluid type identification Resistivity logs can assist in differentiating between oil and gas reservoirs based on the resistivity response of these fluids. 4 Formation evaluation Resistivity logs are used in conjunction with other log data to determine porosity, permeability, and other formation parameters.

26. Density Logs Density logs measure the bulk density of the formation by emitting gamma rays and measuring the amount of radiation that is backscattered to the detector. This backscattered radiation is directly related to the density of the formation. Application Description Porosity Determination Density logs are used to calculate the porosity of the formation by comparing the measured bulk density to the density of the matrix material. Lithology Identification Different lithologies have distinct density values, allowing for the identification of various rock types. Fluid Identification Density logs can differentiate between water-saturated and hydrocarbon-saturated zones based on the density differences between water and hydrocarbons. Reservoir Characterization Density logs provide crucial information for reservoir characterization, including porosity, permeability, and fluid content.

27. Density log: bulk density Photoelectric factor data from a density log

28. Neutron Logs Neutron logs work by bombarding the formation with neutrons and measuring the number of neutrons that return to the detector. They are primarily used to determine the hydrogen content of a formation, which is directly related to the presence of water, oil, and gas. Hydrogen Content Neutron logs are highly sensitive to the presence of hydrogen, which is abundant in water, oil, and gas. Porosity Determination The hydrogen content is closely tied to porosity, enabling the determination of pore space within the formation. Fluid Identification Neutron logs help differentiate between water-saturated and hydrocarbon-saturated zones based on the hydrogen content variations.

29. The log responses for halite, anhydrite, and gypsum This log was recorded of part of the Nippewalla Group Blaine Formation evaporites in a well located in Hamilton County, Kansas.

30. Sonic, or Acoustic, Log Sonic logging Also known as acoustic logging, is a well-logging technique that measures the travel time of acoustic waves through subsurface formations to provide information about the geological and physical properties of these formations. This method involves lowering a tool equipped with acoustic transmitters and receivers into a borehole. The tool generates acoustic waves that travel through the formation and are detected by receivers. Uses Formation Evaluation Hydrocarbon Exploration and Production Geothermal Energy Exploration Mining Sansstone =low Δ t Shales= Δ t Anhydrite=low Δ t Coal=high Δ t

31. Wireline Logging Wireline logging involves lowering logging tools down the borehole on a cable called a wireline. This method is widely used in the oil and gas industry for various applications, including formation evaluation, well completion, and production monitoring. Formation Evaluation Wireline logging provides detailed information about the geological formations, including lithology, porosity, permeability, and fluid content. Well Completion Wireline logging is used to evaluate the effectiveness of well completion operations, ensuring proper wellbore integrity and productivity. Production Monitoring Wireline logging can be employed to monitor production performance, identify potential issues, and optimize well performance. Data Acquisition Wireline logging tools are designed to acquire various types of log data, including resistivity, gamma ray, density, neutron, and sonic logs.

32. Wireline logging traces produced by geophysical logging tools.

33. Several descriptive properties can be derived from the dipmeter survey: Lamination thickness and regularity Layering contrast and frequency Layering continuity Flasering and load structures Dipmeter Logging Dipmeter Log

34. This dipmeter example was run in an offshore well on the east coast Canadian continental shelf. Dipmeter profile and strurcutre determination

35. Continuous dipmeter log and interpretation for part of the Yeso Formation in the Texaco (Steven M. Cather,2009) Tectonics of the Chupadera Mesa region, central New Mexico Steven M. Cather, 2009, pp. 127-138 R. Nurmi, 1984

36. Nuclear magnetic resonance (NMR) logging NMR logs provide information about the quantities of fluids present, the properties of these fluids, and the sizes of the pores containing these fluids. From this information, it is possible to infer or estimate . The volume (porosity) and distribution (permeability) of the rock pore space Rock composition Type and quantity of fluid hydrocarbons Hydrocarbon producibility NMR logging-tool response compared to conventional logging tools. EVALUATION OF LOW RESISTIVITY LOW CONTRAST RESERVOIR(Muhammad Amin Nizar Bin Che Abd Razak,2012 ) Electrical intereferences Low vertical resolution(0.8 ft-3ft) Low logging speed Costly Limited by shell diameter

37. Electrical imaging Assisting sedimentological interpretation Determining the boundaries and thickness of depositional sequence and formations Identifying sedimentary structures, structural features, and lithofacies Determining the geometry and density of fractures and faults Determining the presence of permeability paths and potentially impermeable barriers Distinguishing natural from anthropogenic fractures Planning well completion, perforation, fracturing, or drilling locations

38. Mud Logging  Mud logging (or Wellsite Geology) is a well logging process in which drilling mud and drill bit cuttings from the formation are evaluated during drilling and their properties recorded on a strip chart as a visual analytical tool and stratigraphic cross sectional representation of the well . Provide continuous record of penetration rate, lithology and hydrocarbon shows . These information supports wireline log data . From the cuttings, an oil stains or odor of oil may be detected, become an excellent qualitative indicator .   Example of Mud Logging

39. Seismic logs These are interpretations of seismic reflection data. Seismic surveys emit sound waves that travel through the Earth's layers and reflect back based on acoustic impedance contrasts (differences in density and velocity). By analyzing these reflections, geophysicists create seismic sections that depict the subsurface layering. Uses in Basin Evaluation Identification of basin’s structural history Delineateing the over all shape Stratigraphy Segmentation of megathrust rupture zones from fore-arc deformation patterns over hundreds to millions of years, Arauco Peninsula, Chile(Daniel Melnick,Bodo Bookhagen,Helmut Echtler,2009)

40. Spontaneous Potential (SP) Logs Measures natural electrical voltage differences between a borehole and the surface (without applying any current). Works because of variations in salinity between formation fluids and drilling mud. Helps identify permeable zones (like sand) and impermeable zones (like shale). Indicates the salinity of formation water. Can be used to estimate the amount of clay (shale) in a formation. Requires conductive drilling mud (oil-based mud won't work). Often displayed as a continuous curve with deflections based on formation properties. Limited resolution - may not show thin formation

41. Spontaneous potential (SP) log acquisition schematic SP log and lithology

42. Self Potential Logging

43. The Photoelectric Absorption (PEF) log measures the photoelectric absorption cross-section index of the formations surrounding the borehole. This index is primarily influenced by the atomic number of the elements in the formation, making the PEF log useful for identifying rock types and determining mineral composition. Photoelectric Absorption (PEF) Log Tools used for photo electric data

44. Combination Logs for Interpreting Lithologies Density-Neutron Crossplot Density-neutron crossplot ,  ρ b  versus  ϕ N Photoelectric Factor Versus Bulk Density Crossplot Photoelectric factor versus bulk density crossplot ,  ρ e  versus  Δ t  

45. Sonic-neutron crossplot as a lithology indicator Sonic Versus Neutron Porosity Crossplot Photoelectric Factor From Density Log in Conjunction With Density and Neutron Porosity

46. Combination of gamma ray log,SP log and density log for lithology determination

47. Case Study Permeability and porosity images based on NMR, sonic, and seismic reflectivity: Application to a carbonate aquifer VP and VS plotted against porosity Permeability and porosity images based on NMR, sonic, and seismic reflectivity: Application to a carbonate aquifer(Jorge O Parra,Chris Hackert,2003)

48. Lithology intercepted by well PBF-10 showing VP, VS, bulk density, log-derived porosity and NMR bound volume logs

49. NMR derived permeability and facies evaluation

50. Lithology determination based on porosity and permeability

51. Do You Have Any Questions ?