Summary
Openhole gravel packing is one of the popular completion techniques in
challenging, high-transmissibility reservoirs. Many of such wells are drilled
with synthetic fluids and completed with either a single- or a two-trip
technique.
In single-trip approaches, the entire wellbore is displaced to water-based
fluids before running screens and subsequent gravel packing. Although
successful in some cases, this technique has been problematic in reactive-shale
environments because of problems in screen installation to target depth,
resulting from shale swelling and/or collapse. Such problems led operators to a
two-trip approach in which a predrilled liner is installed in synthetic-based
mud (SBM), displacements are performed to water-based fluids, and the screens
are run in a solids-free (SF) water-based-fluids environment, followed by
gravel packing. In recent years, another approach was introduced, in which the
displacements to water-based fluids are performed after the screens are
installed in conditioned mud and the packer is set, followed by gravel packing
with a water-based fluid. Although this approach eliminates the difficulties
associated with screen installation as well as allowing a single-trip
completion (no predrilled liner), it cannot be used in cases where conditioning
is impractical.
In this paper, we present case histories where screens were installed after
the open hole was displaced to a solids-free SBM and the cased hole was
displaced to completion brine, and gravel packing was performed using a
water-based carrier fluid. This approach provides a cost-effective alternative
to displacement of the entire wellbore to SF-SBM as well as eliminating the
risk of screen plugging, and it was implemented successfully on two oil
producers in Oyo field. Details of design, execution, and evaluation for
drilling and completion stages, as well as well productivity measures, are
provided.
© 2011. Society of Petroleum Engineers
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History
- Original manuscript received:
29 June 2010
- Meeting paper published:
21 September 2010
- Revised manuscript received:
20 November 2010
- Manuscript approved:
5 January 2011
- Published online:
31 May 2011
- Version of record:
13 June 2011