Summary
Four expandable completion liners (ECLs) have been run in Algeria in two
fields--these are the first fully compliant ECLs in Algeria, the first
worldwide in gas wells, and the first worldwide in multilateral wells (from
Weatherford database). This paper presents the first detailed benchmark study
of ECL performance.
All systems to date have been run in 8 1/2-in. hole using 5 1/2-in.
base-pipe ECL compliantly expanded, and the installations went well. It has
been possible to compare ECL performance data against a comprehensive
surveillance data set for the two fields where data from existing openhole
completions allow meaningful comparisons. The other completions consist largely
of slotted liners and some barefoot completions. The tested production rates in
each of the wells have been high relative to normal field trends; however, the
predominant factor in this is the reservoir character. Pressure-buildup (PBU)
analysis indicates that the second well has reduced Darcy skin, while it is
considered unproved in the first well (more data over time are needed). There
is, however, consistent evidence for a reduction in the rate-dependent
proportion of total skin in both wells. This is supported by other studies and
a consideration of basic principles.
The reduction in the rate-dependent proportion of skin has given an increase
in production rate of 5-20% as compared with the computed rate from a slotted
liner. This difference assumes no borehole collapse, with analyses and
discussion presented of the effect on well performance should borehole collapse
occur.
The joint venture (JV) is investigating the further use of this technology
in smaller hole sizes and possibly in conjunction with fracture
stimulation.
© 2011. Society of Petroleum Engineers
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History
- Original manuscript received:
12 April 2010
- Meeting paper published:
9 June 2010
- Revised manuscript received:
19 October 2010
- Manuscript approved:
9 November 2010
- Published online:
18 May 2011
- Version of record:
13 June 2011