Basin Modeling
Overview
GeoMark Research has the knowledge and experience to provide bespoke 1D and map-based basin modeling services. Projects can range from international bid round screening to hydrocarbon phase modeling for development plans. With GeoMark’s talented staff of geologists, geochemists, and engineers as well as access to proprietary datasets and studies, clients can reach the answers they need without even submitting a sample for analysis.
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Additionally, models can be refined by integrating client specific data and providing updates as projects advance, always staying relevant to the questions at hand. GeoMark is a single stop for fully integrated geoscience solutions, from our lab to your field.
Petroleum Systems Modeling Overview
What is Basin Modeling?
Basin modeling is the integration of geology and geochemical data with the basin history to understand and predict the occurrence of petroleum system elements required for a successful play or prospect. Specifically, basin models are critical for characterizing source rock maturity, hydrocarbon generation and phase, migration, and accumulated volume. Basin models can also be designed to target unconventional project needs, such as quantifying the difference between generated and retained hydrocarbons and showing the consequence of gas sorption.
How Do I Use it?
Properly designed and constrained Basin Models provide critical scenario testing to de-risk opportunities across your investment portfolio. GeoMark basin modeling provides not only the maps and data related to source, charge, and preservation risks of your play/prospect, but will help you run scenarios to determine the best course of action to mitigate the uncertainty associated with certain conditions. Use the results from preliminary models to help you risk opportunity areas or landing zone yields. As your project progresses, you can integrate your own specific well and production data into the same model, resulting in business continuity and retained data value. All data generated from the basin model can be delivered to your team for integration into your proprietary subsurface and reservoir models.
What Data Do I Need to Get Started?
GeoMark has an extensive set of pre-existing studies and proprietary data that can be used to start a basin modelling project with very little additional input. However, the best models are those that are built using client generated geologic data such as structure maps, stratigraphic/depositional models and calibration data from wells and other regional sources. Figure 1 below highlights key subsurface elements required for a successful petroleum opportunity and how a basin model address them. The critical processes of source rock maturity and migration are then illustrated after the definitions of the elements are described in the model. The flexibility of this workflow allows for the input parameters to be refined and replaced as additional knowledge and data is captured for the project.
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GeoMark executes our Geochemical Consulting services as an active member of your project the team. We collaborate closely with you to understand the critical scope and goals of the project, and provide a truly integrated product. From our vast experience, we are able to adapt to challenging asset requirements and evolving changes. Nothing is too big or too small—from Pre-Screening Acreage Assessment to Exploration-Exploitation (Appraisal) and Development focused projects.
Petroleum Systems Modeling – Detailed Workflow
GeoMark will generate property maps such as reservoir pressure and temperature, generated oil volume, source rock maturity, etc., and provide them to your team as ready to use inputs for risk assessment and reservoir models. Figure 2 below shows example Maturity, Pressure and Temperature Maps from a recent study completed in a United States Resource Play. GeoMark can also provide the calibration data that was used in the models to constrain these property maps. GeoMark never provides a “black box” product and will openly disclose all data used in the models.
Databasing
Collation and organization of inputs and calibration data is a key step in any petroleum system project. Through access to GeoMark’s proprietary database, RFDbase, information pertaining to hydrocarbon source rock type, source maturity, and source age is already available. RFDbase also contains additional information that can constrain the presence and quality of seal and reservoir rocks. Building off the RFDbase structure, additional client and public data can be added and reviewed to ensure a consistent data model. This project database can then be maintained throughout the life of the project, conquering the constant issue of time spent in collecting and organizing data. Organizing this key information in one place also ensures the longevity of the petroleum system model. It is critical that project teams recognize that the model should be referred to repeatedly and at all key decision points. The model should be designed to test key uncertainties for a given opportunity and these uncertainties will change and evolve as more data is obtained. Project teams should recognize that these uncertainties are not all equal, and the model will focus priorities on those uncertainties that impact economic value and not just geologic variability.
Generation of 1D basin models
One Dimensional models are typically a starting place for petroleum systems models because they are a very tangible product. The final model will provide temperature and maturity estimates related to a well location that can be used to rank source rock and reservoir conditions that are critical to understand the economic potential of a play. They are built around wells or pseudo wells that geologic teams have already recognized as key data locations in their area of interest. The 1-D petroleum system model will use the stratigraphic information confirmed from drilling, including geologic ages, lithologies and depths. In addition, the section encountered during drilling can be extended, ideally to basement, by either collating regional information or inferring seismic data. Thus, the drilling information provides significant constraints to the model, but it will also test various geologic conditions that are not so easily measured such as missing section, thermal history and deposition rate. The project team describes the test conditions to the petroleum system modeler and several iterations can be run so that the team will fully understand the range of potential outcomes. This iterative step is an effective way to test the importance of certain elements. For example, often the source rock of a given play is not directly tested in a well but it might be projected on seismic. This source interval can be added onto known well information, but different depths/burial rates can be tested based on different seismic velocities. The result might be that regardless of seismic velocity, the projected source rock is clearly in the gas window. The project team now knows that the depth range of the source rock does not affect the outcome of its present day maturity window.
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While the individual models are important useful in and of themselves, they are also important elements of further petroleum system work. The results of the 1-D models will be incorporated in future map based, 2-D and full 3D models.
Mapping of Model Properties
Additional basin modeling inputs can come from gridding measured properties across the area of interest. These sorts of maps can include parameters such as direct maturity indicators such as Tmax or vitrinite, source quality indicators from pyrolysis, and even observed hydrocarbon shows that describe migration pathways (See Figure 3 for examples). Gridding these properties correctly requires an understanding of the geologic trends in the basin and the burial history. Appropriate gridding algorithms must be guided by the interpreter so as not to bias the data away from known natural processes. Often, the data available to create these maps is biased by the nature of our own operations: we have more data in shallow location than deep, we drill more highs than lows, etc. This needs to be understood to correct for sampling bias affects. The 1D models can aid in extending the coverage of these parameter maps by being used to create pseudo wells to infill location and extend trends. While these pseudo wells should not be considered “real” data, they are geological valid and constrained modeled locations that are an improvement to simply extrapolation.
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Petroleum Systems Modeling – Detailed Workflow
The last phase of the project is the final integration of all the previously described inputs and calibrated 1-D models with the depositional and history heat flow of the basin. The result is the final petroleum system interpretation and includes a description of identified organofacies, present day maturity of source rocks, likely migration pathways and relationship of hydrocarbon accumulations to source kitchens, and a discussion of PVT conditions and expected hydrocarbon phases (See Figure 4 for example migration map). Additionally, an estimate of volume of hydrocarbon generated and expelled can also be provided, as well as a high-level ranking of identified opportunities.
How is the basin model different than just gridded maps of data sets as described above? Measured properties describe the present-day condition of the sample but does not describe the history that resulted in that outcome. If we rely on present day maturity measurements, our assumptions about fluid properties and things such as kerogen conversion may be inaccurate. A case in point is the modern resource play in the Bakken Formation of the Williston Basin. Direct maturity estimates indicate that the source rock is immature, causing many investors to look elsewhere in the early days of resource plays. Petroleum System modelling that can account for varied kerogen types, depositional history and the potential for charge focus confirm what is known today through decades of production: the Bakken source rock generated significant hydrocarbons and is clearly not immature. A calibrated petroleum system model confirms this and highlights the best places to operate in the basin. Properties that are affected by change over time, such as maturity, overpressure, fetch, and erosion are best captured through petroleum system modeling.
A key aspect of petroleum system modeling is understanding the heat flow history of the source rocks in the basin of interest. When there is limited calibration data available, as is the case in many exploration projects, GeoMark believes in “bottoms up” temperature modelling, starting at the base of the lithosphere and initial formation of the basement, followed by an understanding of the depositional history up to present day, including key geologic events related to erosion, uplift, and thermal anomalies. Fortunately, in many of the most prolific basins, there is ample calibration data and more of a “top down” approach to temperature and pressure modeling can be applied. Integrating available PVT and fluid phase data when available is critical to understanding and predicting fluid at reservoir conditions.
Based on previous experience, it’s important to note that the best petroleum system models come from integrating of the modeling team with the subsurface interpretation team. GeoMark excels in open communication with to ensure that all available data and ranges are best captured in the model and that the end-user fully understands the model content and results. Prior to the final report and project conclusion, GeoMark will submit a draft review that should allow for additional feedback and improvement. The final report should not only address the project goals of completing a geochemical evaluation of the petroleum system but also provide the project team with confidence in its understanding of how to use the report to develop and pursue petroleum opportunities in the region. The most successful project will be a living project that the can referenced and expanded for years to come.