Summary
A big-bore, high-pressure/high-temperature (HP/HT) drilling and completion
program of seven wells was undertaken under challenging conditions in a
low-pressure carbonate reef in Indonesia. Significant enhancements made during
the program substantially reduced well times and cost. These wells incorporated
the largest tubingless gas completions in the world.
Higher-than-anticipated initial flow rates were achieved through an innovative
strategy to decrease formation damage. The wells were completed openhole
without pumping kill-weight fluids at the end of underbalanced drilling (UBD)
operations. These wells are the first to combine big-bore completions, drill-in
liners, and UBD in individual wellbores.
Introduction
The Arun field was initially developed in the 1970s, with world-class gas
reserves at HP/HT conditions. The first big-bore wells were designed and
implemented in the early 1990s to enhance field development. These wells
enabled a maximum gas-flow rate per well and reduced overall field-development
cost by minimizing the number of required wells. Eleven wells were drilled
and completed, realizing flow rates up to 217 MMscf/D each, and were considered
highly successful.
Since the initial drilling program, reservoir pressure in the Arun field has
declined from 7,100 psi to less than 600 psi. As a result, 31 wells have been
lost to formation subsidence and wellbore collapse. This prompted a need for
additional big-bore wells to meet volume requirements. The new wells were
executed under more challenging conditions caused by the severely drawndown
completion interval.
© 2006. Society of Petroleum Engineers
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History
- Original manuscript received:
26 May 2004
- Revised manuscript received:
7 October 2005
- Manuscript approved:
8 November 2005
- Version of record:
20 March 2006
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