Interpreting Well Logs for Inversion Modeling

Questions and Answers

Match the following actions with their corresponding solutions to dealing with spurious data or non-calibrated data:

Remove the well = If enough wells are available to represent the global trend Review the petrophysical editing and/or the calibration of the well concerned = To deal with spurious data or non-calibrated data

Match the following statements with their correct implications:

Without a low-frequency model, only relative impedances can be determined = Due to the band-limited nature of seismic data Including a low-frequency model allows us to recover the absolute acoustic impedance = Effects of having a low-frequency model

Match the following requirements with their descriptions for filtered elastic logs:

Interpolated within defined structural and stratigraphic grid = Filtering elastic logs requirement Thorough QC of all input information before incorporation within the Low Frequency Model = Quality control requirement for filtered elastic logs

Match the following guidelines with their corresponding objectives for incorporating seismic interval velocity in Low Frequency Model:

Include seismic interval velocity as primary data if no well control available = Objective of incorporating seismic interval velocity in absence of well control Include seismic interval velocity as secondary data to guide interpolation away from wells = Guideline for incorporating seismic interval velocity as secondary data Signup and view all the answers

Match the following interpolation methods with their descriptions:

Kriging = Interpolates well information based on geostatistical variogram Collocated co-kriging = Interpolates a primary property using a secondary variable as a trend Signup and view all the answers

Match the following statements with the correct description:

Isotropic Variogram = Variogram ranges are the same in all directions Anisotropic Variogram = Principal range and secondary range, model, and azimuth need to be defined Signup and view all the answers

Match the following log types with their primary usage in the model filling process:

Vp Log = Seismic velocity integration Vs Log = Used to generate equivalent secondary external drift Signup and view all the answers

Match the following statements with their correct role in quality control:

Coherent vertical variation check = Done through 2D sections in different directions Coherent lateral variation check = Done through maps along or between horizons Signup and view all the answers

Match the following seismic velocity integration benefits with their descriptions:

Primary component if well-logs are missing = Seismic velocities can be used Secondary property (external drift) = Guides the interpolation far from wells Signup and view all the answers

Match the following steps in creating a Low Frequency Model with their descriptions:

Estimating low frequency needed to compensate for what is missing in the seismic = Determining the missing low frequencies from seismic data Interpolating the well log properties within the structural grid = Filling in missing data points between known values Creating a structural framework and honoring the geometry = Establishing the overall layout and design for the model Performing quality control before inversion = Checking for errors or inconsistencies in the data Signup and view all the answers

Match the following statements with their correct reasons for building a low-frequency model:

Without low-frequencies, only relative impedances can be determined. = Explaining the limitation of seismic data's frequency spectrum Including a low-frequency model allows recovery of absolute acoustic impedance. = Highlighting the benefit of incorporating low frequencies The acoustic impedance logs contain the full frequency spectrum. = Comparing the information in well logs versus seismic data limitations Low-frequency model serves as starting point for Model Based inversion process. = Describing the role of low-frequency model in inversion Signup and view all the answers

Match the following components with their roles in seismic inversion preparation:

Well logs = Provide detailed property information Horizons = Indicate boundaries between layers Seismic data = Limited in frequency spectrum Low Frequency Model = Compensates for missing low frequencies Signup and view all the answers

Match the following terms with their meanings related to model building:

Acoustic impedance = Resistance to sound wave propagation Relative impedances = Indicate changes between layers Absolute acoustic impedance = Exact measure of sound wave reflection Model Based inversion process = Utilizes initial model as foundation Signup and view all the answers

Match the following concepts with their descriptions related to interpolation:

Low-frequency trends of properties like Vp, Vs, and Density = Patterns used to fill in missing data points Structural and stratigraphic framework = Reference structure for interpolating property trends Filling in missing data points between known values = Completing the dataset by estimating intermediate values Determining the missing low frequencies from seismic data = Identifying and compensating for absent seismic frequencies Signup and view all the answers

Match the following stages with their objectives in seismic inversion preparation:

Discussing importance of Low Frequency Model = Understanding significance of including low frequencies Building a low frequency model using well logs and horizons = Replacing unrecorded low frequencies from seismic data Performing quality control before inversion = Ensuring accuracy and reliability of data Creating a structural framework and honoring geometry = Establishing basis for model building process Signup and view all the answers

Match the following steps with their descriptions in creating a Low Frequency Model:

Grid Building = Creating the structural or stratigraphic grid framework Minimum frequency estimation = Determining the low frequency needed to compensate for what is missing in the seismic Log filtering = Filtering well logs based on seismic minimum frequency Interpolation = Determining the method of inter-well interpolation to avoid local anomalies Signup and view all the answers

Match the following considerations with their descriptions for building a good low frequency model:

Editing and correlation of wells = Ensuring all selected wells undergo necessary editing and correlation Spatial geological variations = Reflecting spatial geological differences in the choice of wells Extrapolation decisions = Making decisions about extrapolation above the shallowest log point and below the deepest log point Inter-well interpolation method = Determining how to interpolate between multiple wells to avoid local anomalies Signup and view all the answers

Match the following guidelines with their descriptions for defining the structural or stratigraphic grid framework:

Capture large-scale structures = Selecting events with high confidence for the grid framework Prefer reservoir top and base = Preferring to pick the reservoir top and base as horizons for the grid framework Cover entire area = Ensuring that horizons cover the entire area for inversion Maintain smoothness = Maintaining smoothness of horizons to avoid artifacts in the model Signup and view all the answers

Match the following interpolation scenarios with their descriptions:

Conformable interpolation = Proportional interpolation between both top and base horizons Top Lap interpolation = Interpolation following the base horizon, with constant thickness Base Lap interpolation = Interpolation following the top horizon, with constant thickness Onlap modeling = Typically used for modeling when seismic events are parallel to top horizon Signup and view all the answers

Match the following methods with their descriptions for estimating the low frequency in a Low Frequency Model:

Logs filtering based on seismic data = Filtering well logs to retain information not captured by seismic data Amplitude spectrum analysis = Considering amplitude spectrum of seismic or estimated wavelet as a first guess Cut-off frequencies determination = Ensuring cut-off frequencies align with minimum frequencies observed in seismic data Low pass filters application = Applying filters to check consistent amplitudes in seismic sections Signup and view all the answers