Lesson 4 Reservoir Management As we have seen, the production of oil and gas up the wellbore and through the surface facilities requires a continuous source of energy. The energy to drive this system is contained in pressed rock and fluids found in the reservoir. Reservoir management is the management of that energy, to maximize the economic recovery of hydrocarbons. This chapter presents an overview of some basic concepts regarding the properties of reservoir rocks and fluids. We shall do this from the perspective of the production or reservoir engineer, who is concerned with how the reservoir rock and fluids behave as production occurs, and with how this behavior affects ultimate recovery. We shall then outline the types of natural reservoir energy responsible for production, and give some examples of the performance characteristics of the primary drive mechanisms. Next, we shall point out the techniques used to enhance the recovery of hydrocarbons, whereby we attempt to alter the physical forces that control the movement of oil within the reservoir. Finally, we will give a brief introduction to reservoir simulation. Basic Properties of Reservoir Rocks and Fluids In order for a geological formation to form mercial reservoir for hydrocarbons, the rock must exhibit two basic properties: porosity and permeability. Porosity is the void space within the reservoir rock, which is filled with water and (hopefully) hydrocarbons. Permeability is the ability of the rock, a porous medium, to transmit fluids. The hydrocarbons that share the porosity with formation water are plex mixtures, that change their properties when subjected to the changes in pressure and temperature panying production. Porosity Porosity is defined as the percentage or fraction of void space to bulk volume of rock. If the sedimentary particles of a rock were of uniform size and packing, as shown in figure , the calculation of porosity would be a simple exercise in solid geometry. Of
