Summary
The source of sand production is the presence of disintegrated sand grains
caused by rock failure at the wellbore and/or perforation walls. Decision for
appropriate sand-control strategy requires engineering analysis to evaluate
timing and severity of sanding over the life of field conditions. Optimizing
well parameters such as well trajectory, perforation orientation, and level of
drawdown using geomechanical principles can minimize and delay sand
production.
This paper presents a geomechanical modeling approach that integrates
production history with information from drilling data, well logs, and
rock-mechanics tests. A gas field in south Asia with 11 wells and several years
of production experience is used to demonstrate this approach. Core-calibrated
rock-strength-log profiles are estimated throughout the reservoir depth for all
existing wells. A rock-failure criterion at the sandface is developed as a
function of in-situ stresses, rock strength, well trajectory, perforation
orientation, reservoir depletion, and drawdown. Sanding-evaluation results are
calibrated and verified with production data and evidence of sanding in
existing wells. Sand-free operating envelopes and sand evaluation logs are then
generated for all existing wells and planned infill wells for the life of field
conditions. Sand-prone zones and timing of sanding are established as a
function of depletion and drawdown for each well, using production forecasts
for the rest of field life. For new infill wells, optimum well trajectories,
selective perforation intervals, and optimum perforation orientations are
proposed to minimize and delay sand production. Recompletion and using passive
sand-control methods including selective and orientated perforations are
recommended for a number of existing wells.
This paper is expected to provide well engineers with guidelines to
understand the principles and overall workflow involved in sand-production
prediction and minimization of sand production risk by optimizing well
trajectory, perforation orientation, and selective-perforation strategy.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
8 July 2008
- Meeting paper published:
22 September 2008
- Revised manuscript received:
30 June 2009
- Manuscript approved:
28 October 2009
- Published online:
23 April 2010
- Version of record:
14 June 2010
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