Summary
Sand production is a critical issue in the oil and gas industry. During the
production of a well, sand production may have negative consequences, such as
risk of well failure, erosion of pipelines and surface facilities, and the need
for sand separation and disposal. Knowing the conditions for the onset of sand
production allows optimizing sand free production and, eventually, avoiding or
delaying the use of sand-control methods.
The aim of this work is to establish a reliable workflow for the estimation
of the conditions for sand production in real field cases by means of
finite-element modeling. The fundamental requirement is to set up a 3D coupled
model that can be easily adjusted to the most complex conditions (e.g., stress
anisotropy, deviated wells, and complex perforation patterns).
The most suitable geometries and associated meshing strategies to describe
the wellbore, the perforation tunnels, and the surrounding formation are
analyzed. Further improvements with respect to previous approaches include the
fact that the drilling and completion phases were also simulated to compute the
correct stress distribution before the production, and that fluid flow and rock
deformation are simulated in a fully coupled way to investigate accurately the
effect of drawdown.
Shear failure of reservoir rock, considered as an elastoplastic medium, is
the main sand-production mechanisms analyzed, and the damage of the rock around
the perforations is evaluated by analyzing the distribution of the equivalent
plastic strain.
Two real field cases are simulated, and the results of the finite-element
models are consistent with the ones obtained by means of an analytical models
and with field observations. Moreover, this numerical approach allows
quantifying the spatial distribution and the severity of the damage of the rock
around the perforations, facts that are either oversimplified or not considered
at all in analytical models.
For future applications, this model can be straightforwardly extended to
more complex conditions and can also be improved to provide volumetric sand
prediction.
© 2013. Society of Petroleum Engineers
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History
- Original manuscript received:
17 February 2011
- Meeting paper published:
20 September 2010
- Revised manuscript received:
8 November 2012
- Manuscript approved:
12 November 2012
- Published online:
25 January 2013
- Version of record:
26 February 2013
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