SPE Production & Operations
Volume 25,
Number 4,
November 2010,
pp. 423-430
Summary
Monitoring deepwater Gulf of Mexico (DW GOM) wells with gravel-pack and
frac-pack completions is an increasingly challenging task. Wells often
experience increasing skin, adding to the risk of completion failure.
Historically, sand-control completions have experienced a 15% rate of
sand-related completion failure (King et al. 2003). The industry tends to
evaluate safe target rates qualitatively as skin increases. Reducing the flow
rate entirely on the basis of an increase in global skin can be too
conservative and can overrestrict target rate. Thus, it is important to know
which components of the increase in skin can cause the completion to fail.
Furthermore, it is not well understood how to quantify a safe target rate with
the increased skin.
This paper will present a new methodology to evaluate the components of skin
increase that could cause sand-control completions to fail. The failure
mechanism we address is perforation plugging by movement of fines and sand. Our
new methodology helps to quantify the risk and convert it into a safe target
rate. This paper will also present case studies of oil and gas wells in the Na
Kika asset in DW GOM where this methodology was applied successfully.
The well completions are monitored with BP's flux-based approach (Tiffin et
al. 2003; Stein et al. 2005; Chitale et al. 2005; Keck et al. 2005). In all
cases, the wells experienced increased skin, causing the engineers to choke
back the wells. The analysis showed that some of the skin increase was because
of multiphase effects as the reservoir pressure was below the saturation
pressure. We also determined which skin components likely caused perforation
plugging, thereby increasing the completion flux. Accounting for
multiphase-flow effects resulted in a higher safe-operating rate limit than
with a conventional analysis. The results allowed the Na Kika asset to produce
these wells at their maximum allowable safe operating rate with the higher skin
while producing within BP's flux-based guidelines.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
4 June 2009
- Meeting paper published:
5 August 2009
- Revised manuscript received:
11 February 2010
- Manuscript approved:
6 April 2010
- Published online:
13 August 2010
- Version of record:
17 November 2010