Page 25 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

8 Bin Yuan and David A. Wood

the loss of surfactants adsorption and precipitation to enhance the stability of
the emulsions (Cuietal.,2011). However, during surfactant-polymer (SP)
flooding, the emulsification effect of surfactant entering the oil phase,
and the possibility of phase separation, may decrease the flowing effi-
ciency of oil into wellbore (Pope et al., 1982).
The most likely formation damage mechanisms during alkaline-
surfactant-polymer (ASP) flooding are fluid-fluid incompatibility and
scale precipitation (Liu et al., 2007). Diverse techniques have been
designed to prevent the problem of scaling, mainly including both chemi-
cal and physical antiscaling techniques (Xu et al., 2001).

1.5 THERMAL RECOVERY IN HEAVY OIL

The associated formation damage mechanisms with thermal recov-
ery in heavy oil include: (1) migration of in-situ fines, kaolinite, detrital
rock fragments, pyrobitumen, and other mobile particulates in clay-
cemented clastic sandstones, and migration of dolomite or carbonate
fines, and pyrobitumen in carbonate reservoirs (Bennion et al., 1995); (2)
inevitably, large amounts of sands production along with the production
of bitumen and heavy oil in less consolidated reservoirs (Tague 2000); (3)
water-phase trapping occurs in heavy oil reservoirs with low permeability
and porosity (Bennion et al., 1996); (4) gas-in-oil foam and water-in-oil
emulsion with significant increase in apparent oil viscosity due to the
entrainment of gas in solution (Chen et al., 2015); (5) clay welling and
defloculation in an abrupt change of brine chemistry (Zhang et al.,
2015a,b), such as fresh or low-salinity water, which can cause constric-
tion, bridging, and blockage to damage permeability and well productiv-
ity; (6) wax and asphaltene deposition (Permadi et al., 2012): asphaltene
coming out of solution as solid particles after destabilization of crude oil
due to the reduction of temperature and pressure or by contact with pre-
cipitating agents, such as unsequestered hydrochloric acid, LPG, and car-
bon dioxide gas; the formation of crystalline wax caused by reduction in
temperature; (7) biologically induced damage (Smith, 1995) including
crude oil souring, blockage of bacteria-produced polyacharride with high
molecular weight to reduce permeability, and mineral erosion due to the
activities of bacteria onto rock surfaces; (8) thermally induced formation