The 2007 SPE/WPC/AAPG/SPEE Petroleum Resources Management System (PRMS)
Authors: Etherington J.R. , Ritter J.E. 
Published: March 2010

Introduction
It is essential that governments, lenders, investors and producers have access to consistent and reliable petroleum reserves and resources assessments, and that results be presented in a common format that communicates the underlying risks and uncertainties.
The task of creating and maintaining the framework and language to support such communication on a global basis has been assumed by a consortium of professional societies led by the Society of Petroleum Engineers (SPE). By late 2004, it became increasingly clear that the current guidance was not sufficient to meet evolving requirements due to advancements in technology, the international expansion of the industry and the increasing role of unconventional resources. The 2007 Petroleum Resources Management System(1) (hereinafter referred to as "PRMS") consolidates and updates prior SPE Reserves and Resources reporting guidance to address this need. The proposed system was subjected to an extensive review process among international stakeholders; the result captures the current consensus of the petroleum industry. This document is co-sponsored by the World Petroleum Council (WPC), the American Association of Petroleum Geologists (AAPG) and the Society of Petroleum Evaluation Engineers (SPEE). It was subsequently also endorsed by the Society of Exploration Geophysicists (SEG).

The Classification System
The quantities of interest are those that can be recovered from a reservoir by a specific project under defined conditions. One project may target several reservoirs and one reservoir can be targeted by several projects, often at different stages of maturity. Evaluations ultimately focus on recoverable quantities and the associated future net revenues; thus, any classification system should be primarily project-based.
All reserves and resources evaluations should be conducted in the context of the full classification system (Figure 1). A property evaluation that reports only reserves is typically incomplete; in almost all cases there will be additional quantities of Contingent and Prospective Resources. PRMS defines a two-dimensional framework wherein projects are classified according to their commercial certainty (the chance of being developed through to producing status) and estimates of recoverable quantities associated with each project are categorized based on technical certainty.
In order to establish a more detailed resources reporting system that can also provide the basis for portfolio management, the commerciality axis may be further subdivided according to standard project status descriptions using one, or a combination, of sub-classification options.
Sub-classes of reserves (Figure 2a) are primarily based on the funding and operational status of projects (developed producing, developed non-producing and undeveloped). Such subdivisions have been traditionally applied to Proved Reserves only, but these same sub-classes may be used for all reserves categories; even Proved Developed Producing estimates have a range of uncertainty.
Evaluators may subdivide Contingent Resources (Figure 2a) based on assumptions regarding changes in future conditions and their impact on economics:
FIGURE 1: SPE resource classification system. Available In Full Paper
Economic Contingent Resources are associated with technically feasible projects that are currently economic, or projected to be economic with reasonably forecast improvements in conditions, but are currently not committed for development.