Page 19 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

2 Bin Yuan and David A. Wood

Formation damage during enhanced oil recovery (EOR) refers to the
impairment of physical, chemical or mechanical properties of petroleum-
bearing formations, primarily due to reservoir permeability degradation
impeding oil and gas flow and recovery. Civan (2015) summarized the
relevant causes of formation damage and its consequences, and various
approaches and techniques for formation assessment, control and remedia-
tion. The changes of chemical-physical-thermodynamic conditions asso-
ciated with EOR techniques can result in various types of formation
damage, i.e., water and bubble blockage, fines migration, fluids-rock
interactions, organic and inorganic precipitation and deposition, scale
formation, alterations of pore surface properties, pore structures and
mechanic characteristics etc. In some cases, formation damage may itself
lead to some benefits which enhance oil recovery, e.g., improve sweep
efficiency thorough selective blockage of high-permeability regions cause
by fines migration Yuan et al. (2017a,b,c); however, more usually, it
reduces the efficiency of secondary and tertiary recovery processes from
the reservoir and impairs well injectivity and/or productivity dramatically.
Porter (1989) and Civan (2015) stated that it is better to avoid formation
than to make tremendous efforts to remediate its effects. Types of
formation damage are realized during drilling, completion, workover,
stimulation, and fluid injection and production operations. The studies of
formation susceptibility to damage have limited practical value if
conducted without linking them to the associated engineering activities,
which may or may not lead to potential damage. Hence, it is an essential
topic for oil operators to understand formation damage specific to various
EOR approaches, because it enables them to maximize oil recovery both
technically and economically by applying EOR techniques to specific
reservoirs with due consideration given to the relevant formation damage
issues. To do that, the comprehensive integration of modelling, simula-
tion, laboratory experiments and field testing are required to predict,
characterize and control any risks of formation damage. Such an approach
also aids the development of new advanced technologies and methodolo-
gies capable of addressing formation damage during secondary and
tertiary recovery processes in both conventional and unconventional
reservoirs. The intention of this work is to provide a better understanding
of the pros and cons of diverse EOR techniques, and to provide guide-
lines on how to control or take advantages of formation damage issues by
optimizing the design of EOR projects.