SPE Production & Operations
It is well documented that hydraulic-fracture treatments, although
successful, often underperform. Frac-and-pack completions exhibit positive skin
values, and traditional hydraulic-fracture completions show discrepancies
between the placed propped length and the effective production fracture length.
Ineffective fracture cleanup is often cited as a likely cause.
This paper presents some of the results of an investigation of
fracture-cleanup mechanisms. This investigation was undertaken under a
joint-industry project (JIP) active since the year 2002. The data discussed
build on the initial results published in early 2006, which indicated that the
polymer concentrates only in the filter cake, and that flow along the fracture
encounters significant yield stress when the filter-cake cumulative thickness
dominates the width of the fracture.
The new results presented here demonstrate successful strategies that
mitigate the effects of excessive filter-cake thickness. Experimental data
demonstrate that flow along the fracture would encounter lower yield stress
when the breaker is delivered directly to the filter cake as opposed to random
distribution. The data also indicate that a smaller breaker amount delivered
directly into the filter cake is more effective at reducing the yield-stress
effects than a larger breaker amount delivered randomly in the slurry.
Alternative breaker materials are explored, and additional data are also
presented to estimate the yield-stress effect for fluid flow across the filter
cake from the reservoir into the fracture.
© 2009. Society of Petroleum Engineers
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- Original manuscript received:
10 July 2006
- Meeting paper published:
24 September 2006
- Revised manuscript received:
9 December 2008
- Manuscript approved:
23 March 2009
- Published online:
30 July 2009
- Version of record:
8 September 2009