The Role of Reservoir Simulation in Optimal Reservoir Management

Abstract

SPE Member Abstract This paper discusses the role reservoir simulators play in formulating initial development plans, history play in formulating initial development plans, history matching and optimising future production and in planning and designing enhanced oil recovery projects. The Hibernia Field in Canada and the Hassi R'Mel in Algeria illustrate how simulation can be used to assist in initial reservoir development. The Lookout Butte Rundle (Alberta) and other are cited to exemplify optimisation of future production plans with the aid of simulation. Finally, applications to plans with the aid of simulation. Finally, applications to several reported EOR projects are briefly discussed with major emphasis concentrating on the Bati Raman Field in Turkey. Introduction The purpose of this paper is to provide an overview on the role of reservoir simulation in managing hydrocarbon reservoirs. As pointed out by Coats, reservoir simulation, in the broad sense, has been practiced, since the 1930's, when some of the first calculational procedures were developed to predict reservoir performance. Here, however, we take a predict reservoir performance. Here, however, we take a narrower view, and restrict our discussion to applications of numerical reservoir simulation. This involves solving large sets of algebraic equations on digital computers to approximate transient, multiphase or multicomponent flow in heterogeneous media. This technology started in the mid to late 1950's and, within the last twenty years, has played an increasingly important role in the development, planning and management of gas and oil reservoirs. In the following, we first discuss the role of reservoir simulation as a tool in planning the initial development of a reservoir. The discussion then turns to their uses as predictive tools when investigating various future operating strategies. Finally, some attention is devoted to their utility in planning and executing enhanced oil recovery schemes. Illustrations in the form of case histories are provided, albeit these are necessarily not detailed because of space limitations. Nevertheless, sufficient references to recent literature on the -subject are given for the interested reader. SIMULATION AND VIRGIN RESERVOIR DEVELOPMENT When a reservoir simulator is employed to assist in planning the development of a virgin reservoir, the planning the development of a virgin reservoir, the reservoir description is typically limited. Consequently, only a minimal degree of optimisation is possible. Nevertheless, some useful insights can be obtained with the aid of a simulator that can minimise the number of decisions one must make in planning field development. In particular, the simulator can and should be used to assess sensitivity in computed results to uncertainties in the reservoir description and rock-fluid data. It is surprising how often variations in input data over reasonable ranges of uncertainty, for some reservoirs, yield modest changes in the computed result. On the other hand, it is useful to know, in the early stages of development, where the greatest effort should be concentrated to obtain those data that affect calculated performance the most. performance the most. Simulation studies at the development stage, because of the uncertainties involved, are regarded as preliminary. Typically, they are periodically updated as preliminary. Typically, they are periodically updated as more information becomes available. This means that early development plans arising from the first simulation studies should be sufficiently flexible to accommodate future contingencies as one learns more about the reservoir. This presents a severe challenge where the reservoir in question is highly complex, large in extent or in a hostile environment all of which may require large investments to put it on production. In cases where the reservoir description and rock-fluid properties are reasonably defined, one can use a simulator to plan well locations and densities assuming voidage replacement by injection to maintain pressure. Such strategic,, can be compared to primary depletion through the same number of wells to arrive at the best development policy for the reservoir. Application to the Hibernia Field To illustrate, we cite the Hibernia Field off the eastern coast of Canada. The field lies about 320 km southeast of St. John's, Newfoundland in a water depth of 80 m. Five wells were drilled to confirm the existence of substantial hydrocarbon reserves in at least two reservoirs, the Avalon and the Hibernia sandstones. P. 13

The use of computer simulations to assess the effectiveness of the revitalization of mature oil fields using the selected reservoir as an example

“…This parameters are dynamic because they are changing in time during the simulation. Every grid block involves solving large sets of simultaneous partial differential equations, which states the mathematical model, to estimate transient, multiphase or multicomponent flow in heterogeneous media [10]. One of the most important equations is continuity equation and principle of mass conservation.…”