Modelling of Time-Dependent Wellbore Collapse in Hard Brittle Shale Formation under Underbalanced Drilling Condition

<table class="figure-group"><tr class="fig-image" id="a"><td><object data="https://static.hindawi.com/articles/geofluids/volume-2019/1201958/figures/1201958.fig.0014a.svgz" name="1201958.fig.0014a" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(a) </b>Equivalent plastic strain distribution after excavation</td></tr><tr class="fig-image" id="b"><td><object data="https://static.hindawi.com/articles/geofluids/volume-2019/1201958/figures/1201958.fig.0014b.svgz" name="1201958.fig.0014b" type="image/svg+xml"></object></td></tr><tr class="fig-caption"><td><b>(b) </b>Equivalent plastic strain distribution after 5 days</td></tr></table>

<div>Progressive failure process of the wellbore with a drilling fluid density of 1.1.</div>

Geofluids

fig14

Figure 14

Figure 14: Modelling of Time-Dependent Wellbore Collapse in Hard Brittle Shale Formation under Underbalanced Drilling Condition 