Gamma ray logs for multiple wells drilled into a sand body (semi-transparent orange) with seismic amplitude shown. Data used by permission of owner.
Accurate analysis of geological and geophysical data is the basis for understanding reservoir characteristics in oil and gas production. An accurate interpretation is essential in determining the economical possibility of the project or any missed opportunity in drilling. To explore the opportunity further, the different geoscientific data including seismic data and well logs can be integrated for deriving the correlation between diverse subsurface properties. This type of integration and analysis can be facilitated within a single 3D geospatial volume which can make multidisciplinary data coordination much more convenient, allowing asset teams to easily access and analyze the data and models essential in making informed decisions regarding hydrocarbon production.
The Importance of Seismic Data and Well Log Data Analysis
Reservoir characterization in hydrocarbon exploration heavily depends on intensive seismic and well log data. The well logs measure the subsurface porosity, permeability, density, and wave velocity along the depths of the borehole through measurement using various logging tools. The measurements, however, can be prone to drilling irregularities. When collecting data from multiple wells, different drilling companies and tool types can skew logs values higher or lower. The time elapsed during the drilling and logging of each can also create variability in the analysis.
Seismic data, on the other hand, indicates various stratigraphic, lithologic, and structural characteristics within the subsurface. The 3D seismic data allows for the analysis of rock properties including thickness, density, porosity, faults, and fractures for hydrocarbon flow within the reservoir. This data aids in the creation of a 3D model of the reservoir which can be analyzed to make informed decisions regarding well location. The accuracy of this data can also be influenced by velocity modelling, seismic bandwidth limitation, and noise error.
The limitations of both seismic and well log data provide an incomplete interpretation of reservoir increasing risks associated with drilling or leading to missed exploration opportunities. The associated risk can be minimized when these geological and geophysical data are integrated and used as a supplement to one another. The proper visualization of this integrated dataset in a 3D geospatial environment further acts to enhance the analysis.
Data Integration for Informed Decision Making
The process of integrating disparate data formats including well logs and seismic surveys can be a challenging task for petroleum engineers and geologists. The difficult integration and multiple cross-interpretational iterations can be alleviated with the help of platforms like CoViz 4D and EarthVision.
The efficient integration of seismic data and well logs into a single 3D geospatial volume allows asset teams to easily access the various datasets and interpretations, identify interpretational variations, and develop interdisciplinary coordination to derive an accurate final analysis. The integration allows:
- Seismic well tie analysis for time and depth correlation measurements
- Property back-interpolation between 2D/ 3D seismic data and well logs for examining property attributes
- Regional context analysis with data correlation throughout the hydrocarbon field for horizon and fault detection
The provision of these interpretations allows for convenient and accurate analysis for estimation and targeting of the project.
Cross plot of seismic amplitude and gamma ray showing low amplitudes (negative values) generally corresponding to lower gamma ray values that indicate sand in a particular field.
CoViz 4D and EarthVision: Facilitating Interpretation with Integration
CoViz 4D and EarthVision are single discipline platforms for efficient integration and visualization of geological and geophysical modules. EarthVision effectively imports and integrates the various datasets and models to create a 3D simulation model facilitating complex correlation analysis between various subsurface characteristics. This analysis aids asset teams in accurately identifying optimal drilling locations for well planning.
CoViz 4D allows asset teams to easily import, integrate, and interpolate seismic data to well logs. The integration offers team members the ability to analyze seismic attributes through seismic cubes and 2D grids to determine location of oil-bearing bodies. From here, the production volume, design, and economic viability of the project can be analyzed. The extensive integration and robust visualization technology reduces uncertainty and facilitates expedited interdisciplinary analysis for efficient decision-making.