A Multi-Purpose Formation Damage Model

Abstract

Abstract A generalized formation damage model capable of simulating a wide variety offormation damage processes encountered in the field is developed. This model was constructed to simulate the chemical, physicochemical, hydrodynamic, thermal and mechanical damage, rock-fluid and fluid-fluid interactions, and the resulting alterations in the reservoir formation. This model has been developed by combining, improving, and generalizing the features of the various modeling approaches reported in the literature for specific applications into one model. The generalized model takes advantage of the fact that the majority of the models has a common ground in the formulation with some variations in the details specific to certain formation damage processes. Introduction Modeling formation damage in petroleum reservoirs 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 reveals 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. The fundamental processes causing damage in petroleum bearing formations are:physico-chemical,chemical,hydrodynamic,thermal, andmechanical. Formation damage studies are carried out for (1) understanding of these processes via laboratory and field testing, (2) development of mathematical models via the description of fundamental mechanisms and processes, (3) optimization for prevention and for reduction of the damage potential of the reservoir formation, and (4) development of formation damage control strategies and remediation methods. These tasks can be accomplished by means of a model assisted data analysis, case studies, and extrapolation and scaling to conditions beyond the limited test conditions. 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 explained in Appendix A. However, the closure of terms involving the spatial deviations by dimensional analysis is reserved for another study.