Chapter 4: Assessment of Petroleum Resources using Deterministic Procedures

This chapter provides additional guidance to the Petroleum Resources Management System (PRMS) 4.1 and 4.2 regarding the application of the three broad categories of deterministic analytical procedures for estimating the range of recoverable quantities of oil and gas. These categories are: analogy, volumetric analysis, and production performance analysis methods, which include material balance, reservoir simulation, decline curve analysis, and other techniques.

In the early days of a project’s life when the project may not have advanced much beyond the development plan, modeling generally will be simple (such as through the use of analogs or volumetric analysis) and then gradually increase in complexity as the project matures. Depending on the scale of the investment, it is not uncommon to have advanced models available (even full-scale reservoir simulations) and ready at sanction. However, it is more common to see a progression of these models throughout the life of the project as the evaluating entity gathers more data and information about the reservoirs being produced. Once the project is fully mature, and only little further investment (financial and/or data acquisition) is anticipated, evaluators may use simpler models such as decline analysis, which rely mainly on the production performance of existing wells.