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Integrating Salinity of Flowback Fluid and Flow Data for Fracture Characterization and Production Forecast in Unconventional Reservoirs
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- Author / Creator
- Zhang, Ganxing
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The complexity inherent in hydraulic fracturing for oil and gas reservoirs demands sophisticated analytical tools for optimal performance and sustainability. The research presented in this study adopts a multi-faceted approach that synergistically combines flow-geochemical models for fracture characterization.
In the initial phase of the research, a coupled flow-geochemical model using commercial simulation software is developed. This model emphasizes the intricate interactions between key components such as oil, original formation water, injected water, and rocks. The model is validated through coreflood experimental data. It provides valuable insights into the complex mechanisms affecting oil recovery during water injection processes with varying salinity. For instance, the model reveals that while ion exchange plays a critical role in high-salinity water flooding, mineral dissolution/precipitation reactions are more dominant in low-salinity scenarios.
Then, the coupled flow-geochemical model is extended to a hydraulically fractured horizontal well model. The modelling results are analyzed to explore the temporal changes in the salinity of flowback fluid and production time. The simulation results are then used to train a set of regression models using Response Surface Modelling (RSM) to predict gas rate and total salinity as a function time for a variety of primary and secondary fracture properties and configurations. Validation exercises demonstrate its robust predictive capabilities, with R2 values consistently above 0.95, confirming the model's reliability and applicability.
In the next phase, the regression models are integrated into an optimization workflow: Genetic Algorithm (RSM-GA) for fracture characterization. Its novelty lies in the integration of salinity in the analysis. The methodology's versatility is assessed across different reservoir and well configurations, including both homogeneous and heterogeneous contexts. It examines the application in different scenarios such as uniform and non-uniform secondary fracture scenarios, heterogeneous fracture patterns, and advanced multi-stage horizontal well frameworks.
Finally, it is found that incorporating fracture parameters estimated from both salinity and rate data, even in the case of multi-stage horizontal wells with non-uniform primary fracture length and spacing or heterogeneous secondary fracture distributions, results in a more accurate representation of the reservoir's behaviour and production history match. -
- Subjects / Keywords
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- Graduation date
- Spring 2024
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.