Page 27 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

10 Bin Yuan and David A. Wood

(Yuan et al., 2015a; Yuan et al., 2016b). Hydraulic fracturing fluids,
formation water, drilling and fracturing chemical additives (proppant,
acids, surfactants, friction reducers, and others), and hydrocarbons are the
common components of produced (flow back) water in such reservoirs
(Ferrer and Thurman, 2015).
Approaches to produced water management for a specific well/field
typically depends on many factors, including: cost, location, local law and
feasible technologies. In general, the commonly applied methods for pro-
duced water management in oil and gas fields mainly include produced
water minimization, produced water recycle/reuse and produced water
disposal (Pichtel, 2016). Among them, produced water reinjection
(PWRI) is an important IOR method with the potential to extend a
reservoir’s economic life, enhance oil recovery, increase water disposal,
comply with national and local regulations, and minimize negative envi-
ronment impacts. In the United States, most of offshore produced water
is reinjected into the formations. However, the implementation of PWRI
usually faces challenges with respect to safety, formation damage and
injectivity, caused by low-quality water contaminated by clays, scale, bac-
teria, and oil droplets (Barkman and Davidson, 1972). When produced
water is reinjected into a formation from an injector, the suspended par-
ticles tend to be deposited into the near-wellbore zones of the reservoir
formations during the invasion process (internal filtration), and an exter-
nal filter cake is formed on the walls of the wellbore (external cake
filtration), resulting in reductions in the injectivity of the injector. The
scale and extent of formation damage by PWRI is determined by the
properties of rocks, such as pores and pore throat size, distribution and
connectivity, as well as characteristics of injected produced water such as
injection rate, temperature, pressure, suspended particle size, particle
distribution, and surface charges (Yuan and Moghanloo, 2016a,b).

1.7 CO 2 FLOODING

The applications of CO 2 EOR projects are mostly accompanied
with severe formation damage issues due to the incompatibility of
injected fluids and reservoir fluids and injected fluids and formation
minerals. The addition of CO 2 brings changes in oil composition and