Summary
Applied research has been undertaken to examine the potential of kaolinite
combined with a kaolinite-fixation agent to increase squeeze lifetime through
alteration of near-wellbore surface characteristics and mineralogy, and to
provide water-shutoff control.
With respect to enhancing squeeze lifetime, it is documented that kaolinite
increases the quantity of inhibitor adsorbed. Conversely, clean sandstone with
low clay content commonly provides a poor substrate for adsorption.
Furthermore, in reservoirs that experience near-wellbore formation damage
because of kaolinite mobilization, it has been shown that the use of a fixation
agent as part of a squeeze treatment can increase squeeze lifetime. Using these
facts, research has assessed the feasibility of injecting microcrystalline
kaolinite (average particle size 2 µm) combined with the fixation agent and
scale inhibitor as a means of mechanically altering near-wellbore mineralogy
and surface-property characteristics within clean, high-permeability
sandstones. The testing has been designed to mimic the squeeze procedure used
in the field for performing such a job and involves no additional steps to
those used in a normal squeeze (i.e., Preflush, Main Treatment, Over-Flush).
The paper presents the results of coreflood experiments that demonstrate
"proof of concept," along with examples of potential field
applications.
A further concept, born from the initial idea, was the use of kaolinite and
fixation agent for efficient, low-cost, environmentally friendly water shutoff.
There are several available products for water shutoff, but the disadvantage of
these is that they are not acceptable for use in Norway because of poor
environmental characteristics. Hence, there was a need to fill this gap by
developing water-shutoff technology to meet country-specific environmental
legislation. The paper provides details of coreflood testing where an excess of
kaolinite has been used to form an internal and external filter cake that is
attached to the wellbore face and within the near-wellbore region using the
fixation agent.
The paper draws on data from StatoilHydro-operated fields in order to
highlight the potential of this innovative approach to downhole scale
management and water control.
© 2009. Society of Petroleum Engineers
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History
- Original manuscript received:
7 March 2008
- Meeting paper published:
28 May 2008
- Revised manuscript received:
29 August 2008
- Manuscript approved:
10 September 2008
- Published online:
30 July 2009
- Version of record:
8 September 2009
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