Application of Memory Concept on Petroleum Reservoir Characterization: A Critical Review

Abstract

Petroleum reservoir rock and fluid properties vary during any pressure disturbances or thermal actions in the reservoir formation. It is important to consider the rock properties such as permeability, porosity, etc. and fluid properties such as viscosity, PVT properties etc. as a function of time for applications including geothermal actions, chemical reactions, and other geological activities in the sub-surface of the reservoir complex structure. Memory is the effect of past events on the present and future course of developments. The continuous alteration of rock/fluid properties can be characterized using memory concept. It is also significant to consider the rock, and fluid properties as a function of time, and the inclusion of recently introduced memory concept in petroleum engineering study. In this paper, a detailed review of the existing techniques and models of reservoir characterization is presented. This study will provide an inclusive information on the present status of memory-based fluid flow modeling, rock and fluid properties models development under spurious assumptions during reservoir characterization. The variations of porosity and permeability over the distance are presented which are from the wellbore towards the outer boundary of the reservoir with time in actual reservoir conditions. Reservoir porosity and permeability are directly related to the reservoir formation depth and pressure. Reservoir porosity and pressure are decreasing over time. Permeability is changed over distance because it is directly related to the pressure of the complex reservoir system. In addition, the viscosity is a function of temperature of crude oil. Since memory-based diffusivity equation through porous media is more rigorous, as it incorporates continuous alteration of rock and fluid, and viscosity of oil predicts results from memory models should be preferred and reliable during the convergence process in reservoir simulators. This paper also aids as an insight of the future research opportunity toward developing models for reservoir properties, and models for fluid flow through porous media in the complex reservoir by the application of memory concept.