Breakthrough in Fracture Modeling for Ultra-Deep Reservoirs: Enhancing Efficiency in Low-Porosity Sandstone Reservoirs
A study by Tarim Oilfield Company and China University of Petroleum has introduced a groundbreaking fracture modeling technique for ultra-deep, low-permeability sandstone reservoirs. This innovative method combines geological data to improve fracture model accuracy. It offers a crucial advantage for efficiently developing these challenging reservoirs.
Key Highlights of the New Fracture Modeling Method:
Geological Information Fusion: The new method combines deterministic modeling for large-scale fractures with stochastic simulation for medium and small-scale fractures. This dual approach enables a comprehensive and accurate representation of fracture distribution, addressing both large fractures and finer geological structures.
Enhanced Seismic Attribute Utilization: By integrating seismic attribute information with geological data using the Permanence of Ratios (PR) model, researchers have developed a fracture development probability field. This field serves as the foundation for constructing a detailed and discrete fracture network model, improving accuracy and predictability.
Application in X Gas Field: The team applied this method to the X Gas Field, located in western China. This field, which features ultra-deep and low-porosity sandstone reservoirs, benefited from the integration of core samples, imaging well logs, and seismic data. The resulting fracture model is highly reliable and aligns with both geological understanding and production dynamics.
Significant Improvements in Fluid Flow Prediction: The new fracture model significantly enhances the prediction of fluid flow characteristics. This is critical for understanding fracture-controlled permeability, optimizing well placement, and improving overall reservoir management strategies.
Geological Context of Ultra-Deep Reservoirs:
The X Gas Field, located in a basin in western China, is a newly discovered trillion-cubic-meter gas reservoir. Its complex structural geology, marked by an elongated anticline with significant fault development, presents unique challenges for reservoir modeling. The Baskichik Formation’s fine sandstone, which exhibits poor matrix properties due to deep compaction and cementation, relies heavily on structural fractures to enhance permeability. These fractures serve as critical pathways for gas migration and production, making accurate fracture modeling essential for effective reservoir management.
Methodological Advances in Fracture Modeling:
Deterministic Modeling for Large-Scale Fractures: The application of 3D seismic data allows for a precise determination of large-scale fracture distribution and geometry. This approach ensures a detailed understanding of extensive fractures within the reservoir.
Stochastic Simulation for Medium and Small-Scale Fractures: A probability field constrained by multiple geological and seismic factors is used to simulate smaller fractures. This detailed approach ensures that even medium and small fractures are accurately represented, providing a realistic fracture network model.
Integration and Validation: The combination of geological and seismic data ensures that the resulting fracture models are both accurate and reliable. This integrated approach forms the foundation for the development of efficient reservoir management strategies.
Conclusion:
The breakthrough fracture modeling method introduced in this study marks a significant advancement in reservoir engineering, particularly for ultra-deep and low-permeability sandstone reservoirs. By improving the accuracy and reliability of fracture models, this innovative approach provides a powerful tool for the exploration and development of challenging reservoirs, leading to better gas recovery rates and more effective reservoir management.
This success story from the X Gas Field sets a promising precedent for the application of this method in other complex geological settings, potentially revolutionizing the way ultra-deep reservoirs are exploited.
For more detailed insights into fracture modeling and the geology of unconventional reservoirs, explore the following articles:
Hydraulic Fracturing: An Essential Tool in Reservoir Development
The Importance of Reservoir Evaluations for Understanding Reservoir Geology
Safety: Our Commitment to Protecting People and the Environment
This innovative fracture modeling technique is a pivotal step forward in the efficient management and recovery of challenging oil and gas reservoirs, setting the stage for future developments in the industry.
Published by: Frontiers in Earth Science
This article is based on the study “A Fracture Modeling Method for Ultra-Deep Reservoirs Based on Geologic Information Fusion: An Application to Low Porosity Sandstone Reservoirs in the X Gas Field of a Basin in Western China,” by Rujun Wang et al., published in Frontiers in Earth Science.
For more in-depth reading, visit the full study here.
