Summary
In a deepwater west African field, the relatively small number of high-cost,
highly productive wells, coupled with a high barium sulfate scaling tendency
(upon waterflood breakthrough of injected seawater) requires effective scale
management along with removal of near-wellbore damage in order to achieve high
hydrocarbon recovery.
The nature of the well-completion strategy in the field (frac packs for sand
control) had resulted in some wells with higher-than-expected skin values owing
to drilling fluid losses, residual fracture gel, fluid loss agents, and fines
mobilization within the frac packs.
The paper will present how the challenges of managing impaired completions
and inorganic scale forced innovation in terms of when to apply both
stimulation and scale-inhibitor packages to deepwater wells. This paper will
outline a novel process for non-conventional batch chemical applications where
bullhead stimulation treatments have been displaced deep into the formation
(> 20 ft) using a scale inhibitor overflush. Not only does this benefit the
stimulation by displacing the spent acid and reagents away from the immediate
wellbore area, but the combined treatment provides a cost savings with a single
mobilization for the combined treatment. The paper will describe the laboratory
testing that was performed to qualify the treatments. The four field treatments
that were performed demonstrate how these coupled applications have proven very
effective at both well stimulation/skin reduction and scale-inhibitor placement
before and after seawater breakthrough. The term "squimulation" is used by the
local operations team to describe this simultaneous squeeze-and-stimulation
process.
Many similar fields are currently being developed in the Campos basin (Gulf
of Mexico) and west Africa, and this paper presents a good example of
best-practice sharing from another oil basin.
© 2013. Society of Petroleum Engineers
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History
- Original manuscript received:
24 November 2011
- Meeting paper published:
15 February 2012
- Revised manuscript received:
9 October 2012
- Manuscript approved:
31 October 2012
- Published online:
7 February 2013
- Version of record:
26 February 2013
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