Abstract.

A consistent screening technique was developed to quickly evaluate the Improved Oil Recovery (IOR) potential of oil reservoirs. This evaluation consists of: checking reservoir's geological /production data for consistency, selection of technically feasible IOR processes, performance projection for the selected IOR processes, and generating a complete IOR report, containing all the production and injection plots.

A software (PRIzeTM) was built based on this screening technique. This computer program generates information on the feasibility of IOR processes based on the average reservoir parameter values, the driving mechanisms, and the current understanding of IOR processes; analytical models are used for most predictions. These analytical models have been selected by distilling a significant number of forecasting methods in the open literature.

This paper discusses the PRIzeTM-based experience in evaluating the potential of waterflooding, chemically assisted waterflooding, miscible gas injection (CO2, hydrocarbon, and N2), and thermal recovery processes (steam drive, SAGD and in-situ combustion). Options for using horizontal wells in conventional oil recovery and IOR processes are also addressed. Although PRIzeTM is not a numerical simulator, it allows one to establish, to a first order approximation, the likely performance for determining economic viability of a given IOR process. can, in turn, be used for risk and economic

INTRODUCTION

analyses.

The screening criteria are based on Selection of Improved Oil Recovery statistics of successful commercial IOR (IOR) process is extremely important projects worldwide. All reservoir because, as a rule only 10% of the total IOR engineering equations and algorithms used pilots have been developed into to generate the oil recovery forecasts of semi-commercial and commercial individual IOR schemes have been operations. This figure was generated from established by distillation of a significant a 2-decade statistics on IOR pilots in number of forecast methods existing in the USA1,2. Many of IOR field pilots have open technical literature. When necessary failed because the most appropriate IOR they were improved using our own method was not chosen. To assist in this, a experience. specialized software, PRIzeTM, was created With the exception of steam in 1992, and has been continuously assisted gravity drainage (SAGD), the updated and improved since. Our intent screening and the prediction calculations are here is to present the technical content of performed only for IOR methods, which are this software. proven via commercial operations.

A general IOR method, applicable However, we included SAGD because of an to the complete range of field situations, impressive success in a semi-commerci

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