6X: Using the full stress tensor to predict stress shadowing

Contact: info@ridgewaykite.com | ridgewaykite.com

Extracted from: StressShadowing.pdf

Stress shadowing - modelling the effect of well and stage spacing on the induced stress field

Stress shadowing occurs when the induced stress field from the hydraulic fracturing of one stage influences subsequent stages. Stages must be close enough for the induced stress field to reach the next stage; the closer the stages, the stronger the effect.

To model stress shadowing the simulator needs a geomechanics model that solves at least for the normal stress tensor components, not only hydrostatic mean stress. 6X supports this.

Solving only for mean stress

The simplest 6X geomechanics model uses only the average of the normal stress tensor components (mean stress). In a single-well study with close stage spacing, this shows no stress shadowing. The PDF figure shows dynamic permeability for eight consecutive stages: each stage repeats the same SRV pattern regardless of prior stages.

Plotting mean stress along the well just before stage 2 injection shows mean stress (red) tracks fracture pressure (blue) and matrix pressure (green). Neither has significant values at the second stage (dotted blue), so no shadowing appears.

Solving for the full stress tensor

The advanced 6X model solves each stress tensor component for more detailed rock breakage. Normal components along the well before stage 2 are non-zero at the next stage even when they sum to zero mean stress - so shadowing can appear. The PDF shows dynamic permeability reflecting stress influence on later stages.

Figures (see original PDF)

Plots include dynamic permeability (eight stages, mean-stress model), pressures and mean stress along the well before stage 2, and permeability with the full tensor model.

Figures are not reproduced in this export.

Use the 6X full stress tensor option to understand the effect of previous stages and nearby wells on SRV development.