Directive 065: Resources Applications for Oil and Gas Reservoirs ...

2.5 Application for Pool Delineation and Ultimate Reserves
2.5.1 Background
The ERCB establishes pool boundaries (vertically and horizontally) and assigns reserves to
all oil and gas pools in Alberta. These are shown in Pool Orders (G Orders), annual reserve
publications, and individual well and pool files. Well licensees of new oil wells outside of
established G Orders must submit a completed application for a New Well Base Allowable or
Base MRL (O-38 form).
The initial oil volume or gas volume in place for new pools is often based on simple buildingblock
assignment areas and wellbore parameters. Initially, recovery factors for new pools
may be based on analog pools in the area. Initial delineation reflects early geological and
pressure information. As the pools are developed and further well data and performance data
are available, delineation and reserves may be adjusted to reflect this new information. Net
pay isopach maps, material balance analyses, decline analyses, and analytical and numerical
models may take the place of the simple building-block approach. Different pressure trends
or new gas/oil or oil/water interface information may alter pool boundaries.
The interpretation of pool reserves and delineation can affect regulatory requirements related
to the operation and development of oil and gas pools in Alberta, as well as equity-related
issues between operators.
2.5.2 When to Make This Application
Following the initial well assignment and if additional information becomes available that
substantially changes current decisions, a well licensee may choose to, and in fact is
encouraged to, make an application to change assigned reserves or vary pool delineation for
several reasons, including
• conservation (For example, new evidence may permit a restricted gas well to produce if
it is no longer within a gas cap or the second well in a DSU.)
• equity (For example, new evidence supports delineation for a well to a pool with a higher
MRL or GPP.)
• future applications (For example, while reserves evaluations are required in many other
applications in this directive, an applicant may choose to file a standalone reserve
application. Maintaining a common reservoir information base or understanding
differences may assist or accelerate processing future applications for matters addressed
in this directive.)
• provincial records (For example, pool boundaries and reserves are the foundation for
conservation and equity protection.)
The ERCB monitors pool performance and interprets new well information. As a result, the
ERCB may also request well licensees to file reserve submissions to update reserves for pools
of provincial significance.
ERCB Directive 065: Resources Applications / Pool Delineation and Ultimate Reserves (October 2011) • 2-27