Evaluation and Comparison of the Formation Damage Models

Abstract

SPE Member Abstract An evaluation and comparison of six selected models bearing direct relevance to formation damage prediction for petroleum reservoirs are carried out. The modeling approaches and assumptions are identified, interpreted, and compared. The model equations are presented according to the SPE symbols Standard and Units. It is concluded that the present models are applicable for special cases involving single-phase fluid systems in petroleum reservoirs. Introduction In spite of many experimental studies of the formation damage of oil and gas bearing formations, there have been only a few reported attempts to mathematically model the process. The utilization of these models in actual reservoir analysis and management has been rather limited because of the difficulties in the understanding and implementation of these models. Formation damage in petroleum reservoirs occurs as a consequence of the combined effects of many complicated phenomena. The extent of damage depends on the properties of the fluids and the geological porous media, and the nature of fluid-fluid and rock-fluid interactions. Therefore, formation damage modeling should account for dissolution and precipitation reactions, pore deformation and collapse and sand production phenomena, particulate processes in porous phenomena, particulate processes in porous structure, swelling of porous matrix and clay particles, effects of adsorption, absorption, and particles, effects of adsorption, absorption, and multiphase fluid systems, wettability alteration, and temperature and net stress variations. By and large the present formation damage models consider a single fluid phase and the dominant formation damage mechanism is assumed to be the mobilization, migration, and retention of fine particles in porous matrix. Although, these particles in porous matrix. Although, these models have been validated using experimental data obtained from reservoir core samples under controlled laboratory conditions, their applicability is rather limited in the field conditions. However, it is instructive to examine the logical reasoning and assumptions beyond these models to judge their capability and to determine the potential improvements. This paper presents a critical evaluation, classification, and consistent documentation of the six selected models that have direct bearing to formation damage prediction in petroleum reservoirs. The nomenclature and units used in these models are converted according to the SPE Symbols Standard and nits. The assumptions, limitations, and capabilities inherent in these models as well as the model equations, including the initial and boundary conditions, are tabulated in a systematic manner. A list of the constants and parameters involved in these models and the methods for determination of their values are presented. The formulations presented in this presented. The formulations presented in this paper have minor differences from the original paper have minor differences from the original formulations to maintain consistency. REFORMULATION OF FORMATION DAMAGE MODELS Six models bearing direct relevance to reservoir formation damage are reformulated in a consistent manner for direct comparison. Porous media is considered in two parts:The flowing phase, denoted by the subscript f, consists of a suspension of fine particles flowing through andThe stationary phase, denoted by the subscripts, consists of the porous matrix and the particles retrained. P. 219