Page 18 - Reservoir Formation Damage

Overview of Formation Damage 3

In the past, numerous experimental and theoretical studies have been
carried out for the purpose of understanding the factors and mechanisms
that govern the phenomena involving formation damage. Although vari-
ous results were obtained from these studies, a unified theory and ap-
proach still does not exist.
Civan (1996) explains:

A formation damage model is a dynamic relationship expressing the
fluid transport capability of porous medium undergoing various
alteration processes. Modeling formation damage in petroleum res-
ervoirs has been of continuing interest. Although many models have
been proposed, these models do not have the general applicability.
However, an examination of the various modeling approaches re-
veals that these models share a common ground and, therefore, a
general model can be developed, from which these models can be
derived. Although modeling based on well accepted theoretical
analyses is desirable and accurate, macroscopic formation damage
modeling often relies on some intuition and empiricism inferred by
the insight gained from experimental studies.

As J. Willard Gibbs stated in a practical manner: "The purpose of a theory
is to find that viewpoint from which experimental observations appear
to fit the pattern" (Duda, 1990).
Civan (1996) states:
The fundamental processes causing damage in petroleum bearing
formations are: (1) physico-chemical, (2) chemical, (3) hydrody-
namic, (4) thermal, and (5) mechanical. Formation damage studies
are carried out for (1) understanding of these processes via labora-
tory and field testing, (2) development of mathematical models via
the description of fundamental mechanisms and processes, (3) opti-
mization for prevention and/or reduction of the damage potential of
the reservoir formation, and (4) development of formation damage
control strategies and remediation methods. These tasks can be accom-
plished by means of a model assisted data analysis, case studies, and
extrapolation and scaling to conditions beyond the limited test condi-
tions. The formulation of the general purpose formation damage model
is presented by describing the relevant phenomena on the macroscopic
scale; i.e. by representative elementary porous media averaging.

As stated by Civan (1990):
Development of a numerical solution scheme for the highly non-linear
phenomenological model and its modification and verification by