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

<table class="table-group" id="tab4"><tr><td><table class="table"><tr><td class="thead-hr" colspan="4"><hr/></td></tr><tr class="thead"><td class="align_left">Layer</td><td class="align_center">Formation pressure coefficient</td><td class="align_center">Collapse pressure coefficient</td><td class="align_center">Fracture pressure coefficient</td></tr><tr><td class="thead-hr" colspan="4"><hr/></td></tr><tr><td class="align_left">Es1</td><td class="align_center">1.31</td><td class="align_center">1.32</td><td class="align_center">1.8</td></tr><tr><td class="align_left">Es2, Es3</td><td class="align_center">1.30</td><td class="align_center">1.33</td><td class="align_center">1.93</td></tr><tr class="table-tr"><td colspan="4"><hr class="tbody-hr"/></td></tr></table></td></tr></table>

<div>Pressure tests of the Shahejie Formation.</div>

Geofluids

tab4

Table 4

Table 4: Modelling of Time-Dependent Wellbore Collapse in Hard Brittle Shale Formation under Underbalanced Drilling Condition 