SPE Production & Operations
Volume 25,
Number 4,
November 2010,
pp. 524-532
Summary
Squeezing of clean, high-permeability reservoirs frequently results in
relatively short treatment lifetimes because of the low inhibitor-adsorption
rates achieved. One of the main controls on inhibitor retention is
near-wellbore mineralogy. Clay-rich reservoirs that contain abundant kaolinite,
for example, often have long squeeze lifetimes because enhanced inhibitor
adsorption can occur on the clay surface. The occurrence of calcium carbonate
(CaCO3) cement in the near-wellbore region can also enhance
inhibitor retention by forming a Ca2+/inhibitor complex.
Previously published research (Fleming et al. 2009a) demonstrated the
potential to mechanically alter the near-wellbore region through incorporation
of low concentrations of kaolinite and organosilane. The data presented in the
present work show that the additional incorporation of calcium carbonate
provides a step change in the potential squeeze lifetimes achieved. This paper
will present the results of using low, nondamaging concentrations of kaolinite
and calcium carbonate particles in the preflush followed by scale inhibitor and
organosilane in the main treatment. The kaolinite particles are retained in the
near-wellbore region by the organosilane and enhance the number of potential
sites for inhibitor adorption. At the same time, dissolution of the calcium
carbonate particles by the acidic scale inhibitor forms a
Ca2+/inhibitor complex that further enhances inhibitor
retention.
A review of the technology performance envelope has been made through
coreflooding that includes optimizing the concentration of injection particles
vs. permeability, the ratio of injected kaolinite to carbonate particles, and
performance at elevated temperature (175°C) along with an assessment of how
often a well would require retreatment with particles. The latter has involved
successive coreflooding of the same plug with the full treatment package
followed by brine flowback and retreatment with scale inhibitor alone or with
organosilane. This information can be used by the assets in their evaluation on
potential use of the technology.
© 2010. Society of Petroleum Engineers
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History
- Original manuscript received:
11 February 2010
- Meeting paper published:
27 May 2010
- Manuscript approved:
2 June 2010
- Published online:
22 July 2010
- Version of record:
17 November 2010
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