Borehole Breakout and Sanding During Production
Drilling and production can lead to formation damage and potential borehole breakouts resulting in drill string damage, borehole collapse, sand production or loss of mud. Itasca Consulting Group offers geomechanical modeling services and software that are based on both continuum and discrete element representations of the medium. These tools, along with laboratory and field-testing, can be used effectively to understand and optimize production.
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Dog-ear shaped breakouts
Cusp-shaped breakouts
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When breakout is caused by shear failure and shear banding "dog-ear" shaped breakouts are observed. A continuum analysis modeling approach using Itasca’s FLAC and FLAC3D closely matches field and laboratory observations and helps understand this process.
Reference
Detournay, C., B. Wu and C. Tan (2004) Hydro-mechanical modeling of damage around borehole in laboratory experiments, ARMA/NARMS 04-590
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FLAC results showing dog-ear shaped breakouts in a low permeability sandstone |
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In some sandstones breakouts start in a cusp shape, which could be promoted by damage. In a continuum analysis approach, damage extension is not represented completely. In a distinct element approach using Itasca’s PFC2D/PFC3D software, a large assembly of small (cylindrical or spherical) particles bonded together exhibits rich macroscopic behavior, which can capture the behavior of the formation more accurately. In the adjacent figure a PFC model of a borehole with a cusp-shaped breakout captures observed breakout processes very well.
Reference
Detournay, C., B. Wu and C. Tan (2004) Hydro-mechanical modeling of damage around borehole in laboratory experiments, ARMA/NARMS 04-590
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Cusp-shaped breakout simulated by PFC due to high compressive stresses and particle splitting at the tips |
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