Hi everyone,
I am working on a 2D XFEM-CZM based hydraulic fracturing simulation in Abaqus for a 100 m × 100 m domain with a wellbore at the center. I am using coupled pore pressure–displacement elements (CPE4P) and applying fluid injection to simulate fracture propagation.My model setup is as follows:
I created a 100 m × 100 m rectangular domain.
At the center of the domain, I created a wellbore.
I defined a predefined crack near the wellbore region.
I assigned the required material properties.
In the Boundary Conditions, I applied pore pressure to the entire domain.
In the Predefined Fields, I assigned:
Initial stress
Void ratio
Saturation
In the Load module, I applied surface pore fluid pressure at the wellbore boundary.
For fracture modeling, I enabled XFEM with special crack.
For analysis steps, I used:
Geostatic step (to establish in-situ stress condition)
Soils step (for hydraulic fracturing simulation)
However, I am facing the following issues:
Pore Pressure Issue:
When I apply pore pressure over the entire domain, the fracture propagates, but the pore pressure contour shows almost no variation (appears constant).
When I try to apply it only at the wellbore, I am unsure about the correct way to define the boundary condition
Time Step Issue:
The analysis time step becomes extremely small (on the order of 1e-10), whereas in research papers, the total injection time is typically around 1000–2000 seconds. My simulation struggles to progress due to very small increments.MY STEP TIME IS TWO LOW STARTS WITH 1E-10
My Questions:
Should pore pressure be applied over the entire domain or only at the wellbore boundary for hydraulic fracturing simulations?
What is the correct way to model THIS?
Why does the pore pressure field not evolve even though fracture propagation occurs?
How can I avoid extremely small time increments and reach realistic simulation times (e.g., ~1000 s)?
Any guidance or suggestions would be greatly appreciated.
thank you!
