SMP and Fracture Modeling

Description

The problem of loss circulation in geothermal wells is inherently challenging due to high temperatures, brittle rocks, and presence of abundant fractures. Because of the inherent challenges in geothermal environments, there are limitations in selecting proper lost circulation materials (LCMs). Traditional LCMs such as calcium carbonates that are commonly used in the oil and gas drilling may be softened and prone to failure during geothermal drilling. Moreover, evaluating the performance of different LCMs for geothermal drilling requires unique testing setups, which is expensive, and complicated to run due to harsh environmental conditions of geothermal systems. Herein, we present a numerical approach to simulate LCM transport and bridging through fractures in downhole conditions. By discrete element methods, each individual particle trajectory, and their interactions with the fluid and surrounding particles are incorporated into the analysis. To validate the model, we used experimental results acquired from a high-temperature flow loop system built specifically for this purpose. We took a further step in this work and considered LCM particles that are made from a shape memory polymer (SMP). These particles start expanding and adhering to each other in downhole conditions. The use of SMP is shown to be advantageous in sealing large fractures (3 mm aperture). We demonstrated how numerical modelling may supplement laboratory tests to show initiation of the bridging process, fracture plugging or even its failure. Using the proposed methodology may significantly reduce the number of experiments needed to find an effective LCM recipe, hence drillers can save time and costs by assessing different LCM systems numerically.

Resources

Name Format Description Link
10 We conducted a series of numerical simulations and found the composition of the optimal bimodal distribution by expanding the concept of size mixtures. https://gdr.openei.org/files/1459/SMP%20Modeling_Optimal%20bimodal%20distribution.docx
33 Paper titled "Modelling of cohesive expandable LCMs for fractures with large apertures" associated with these data. The paper was published in Geothermics 104 (2022) 102466. https://gdr.openei.org/files/1459/Geothermics_Modelling%20of%20cohesive%20expandable%20LCMs%20for%20fractures%20with%20large%20apertures.pdf
10 After building the CFD model, the coupled CFD-DEM simulations were used to generate about 100 cases that have different particle size distributions (PSD). We have determined that the best fracture sealing results come from the bimodal distribution designs. https://gdr.openei.org/files/1459/SMP%20Modeling_%20PSD%20and%20effectiveness%20in%20fracture%20sealing.docx
10 The coupled CFD-DEM model is used to simulate the flow of SMP in drilling fluid and modeling of cohesive expandable LCM's for fractures with large apertures. The simulation domain is a wellbore-geometry setup similar to the experimental setup (HT dynamic LCM testing unit). The sealing results show that the SMP accumulate at the fracture entrance, where violent particle collisions occur. A small plug forms and then gradually invade deeper into the fracture. https://gdr.openei.org/files/1459/SMP%20Modeling_Modeling%20of%20Cohesive%20Expandable%20LCMs%20for%20Fractures%20with%20Large%20Apertures.docx

Tags

  • processed-data
  • modeling
  • discrete-element-methods
  • lost-circulation-material
  • dem
  • economic
  • lost-circulation
  • drilling
  • lcm
  • fracture-sealing
  • technology
  • cfd
  • computational-fluid-dynamics
  • shape-memory-polymer
  • smp
  • geothermal
  • energy

Topics

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