The Montney Formation remains one of North America's most important unconventional resource plays, but its geological complexity continues to challenge geoscientists and engineers tasked with building reliable geomechanical models. Variations in lithology, burial depth, and regional heterogeneity can significantly influence wellbore stability, completion design, and long-term field development decisions.
To help address these challenges, Ikon Science researchers Dr. Rashad Gulmammadov and Jakob Heller consolidated and analyzed an extensive regional rock mechanics database spanning approximately 50 wells across the Montney play. The objective was straightforward: develop practical, Montney-specific relationships that allow static rock mechanical properties to be predicted from routine sonic and density logs where core measurements are limited or unavailable.
Ikon Science authors Dr. Rashad Gulmammadov and Jakob Heller were Published in the June 2026 American Rock Mechanics Association (ARMA) 60th U.S. Rock Mechanics Geomechanics Symposium.
Reliable geomechanical models require static rock properties such as Young's modulus, Poisson's ratio, unconfined compressive strength (UCS), friction angle, and tensile strength. However, these properties are typically measured from laboratory testing of core samples, which are often sparse and expensive to acquire.
By contrast, sonic and density logs are routinely available and provide continuous subsurface coverage. The challenge is that these measurements yield dynamic properties, which can differ significantly from the static properties required for geomechanical workflows due to strain-rate and frequency effects.
This study demonstrates how a regionally calibrated dataset can bridge that gap and support more consistent geomechanical characterization across the Montney.
The study compiled laboratory and log-derived data from approximately 50 wells distributed across the Montney play and selected adjacent formations. The resulting database contains more than 500 elastic property measurements and approximately 100 strength-related measurements. Laboratory measurements were integrated with matched sonic and density log data to support direct comparison between core-derived and log-derived rock properties.
Regional coverage and summary statistics for the compiled Montney rock mechanics database.
The database included:
The inclusion of adjacent non-Montney formations provided valuable regional context while maintaining a primary focus on developing Montney-specific predictive relationships.
One of the clearest trends observed in the study was the systematic difference between static and dynamic Young's modulus. Across the dataset, static modulus values were consistently lower than dynamic measurements, although the relationship remained strongly correlated.
For practical geomechanical applications, the most important workflow is converting log-derived dynamic modulus into static modulus suitable for mechanical earth models, wellbore stability analysis, and completion design. The study found that an exponential transform provided the most representative fit for this relationship.
Static Young's modulus exhibits a strong but non-linear relationship with dynamic modulus, enabling log-based prediction of static stiffness.
The resulting transform allows operators to generate continuous static Young's modulus profiles directly from routine well log data, supporting geomechanical workflows in wells without extensive core coverage.
Unlike Young's modulus, Poisson's ratio showed remarkably consistent agreement between static and dynamic measurements. The compiled dataset demonstrated that static and dynamic values cluster closely around a 1:1 relationship, with no significant systematic bias observed.
This finding supports a practical simplification for Montney geomechanics: dynamic Poisson's ratio derived from sonic logs can generally be used directly as the static input parameter without requiring a separate calibration or correction transform.
Dynamic and static Poisson's ratio measurements cluster near the 1:1 line across the regional dataset.
Unconfined compressive strength (UCS) is a critical parameter for wellbore stability assessment, drilling performance analysis, and hydraulic fracturing design. Yet UCS measurements are frequently unavailable outside cored intervals.
The regional database revealed a clear positive relationship between compressional wave velocity and UCS. Both linear and power-law models were evaluated; however, the linear relationship provided the most stable and practical predictor for the current dataset.
UCS increases systematically with compressional velocity, enabling continuous strength estimation from sonic logs.
This relationship enables geoscientists and engineers to generate continuous UCS profiles directly from sonic logs, improving mechanical characterization in uncored wells and supporting more robust predictive geomechanical models.
While UCS and Young's modulus showed useful predictive relationships, friction angle behaved differently.
The study found only weak correlations between friction angle and compressional velocity. Significant scatter across the dataset indicates that velocity alone does not adequately capture the geological and mechanical controls influencing friction angle. Factors such as grain fabric, mineralogy, cementation, bedding characteristics, and testing methodology are likely contributors. [Manuscript | PDF]
Across the regional database, Montney friction angles clustered around approximately 44 degrees, supporting the use of friction angle as a formation-level parameter combined with uncertainty bounds rather than a deterministic log-derived property.
Friction angle displays substantial variability and weak dependence on compressional velocity.
Tensile strength plays an important role in fracture initiation and hydraulic fracturing workflows, but direct laboratory measurements remain relatively limited.
The study observed a proportional relationship between UCS and tensile strength. Analysis of the dataset indicated that tensile strength can be approximated as roughly one-fifteenth of UCS when using the log-based workflow developed in this study.
Tensile strength exhibits a proportional relationship with UCS across the compiled dataset.
This provides a practical method for populating tensile strength logs and hydraulic fracturing models in areas lacking direct laboratory testing.
The most important outcome of this work is not a single correlation, but a complete, integrated framework for deriving rock mechanical properties from routine well logs. The study provides guidance on which properties can be predicted reliably from logs, which require calibration transforms, and which should be treated as formation-level parameters with uncertainty ranges.
The recommended Montney workflow can be summarized as follows:
The authors note several opportunities for future refinement, including expansion of the database, evaluation of stratigraphic subzone-specific relationships, and investigation of anisotropic mechanical behavior within the Montney. As additional laboratory measurements become available, predictive relationships may be further improved and validated against field performance and post-drill geomechanical models.
For operators seeking reliable geomechanical inputs in data-limited environments, this regional synthesis demonstrates the value of combining historical laboratory measurements with routine well logs to build scalable, predictive geomechanical workflows across the Montney play.
Gulmammadov, R. and Heller, J., Regional Synthesis of Rock Mechanical Properties for Predictive Geomechanics in the Montney Unconventional Play, ARMA 26-81, American Rock Mechanics Association Symposium, 2026.