Simonette Beaverhill Lake A & B Pools: A Modern Example of Short Cycle Time Development
Authors: Moynihan T.J. , Fryters J.C. , Chernik P. 
Published: December 2007

The Simonette Beaverhill Lake A and B Pools were discovered in September 1993. Enhanced recovery by WAG miscible flooding was initiated in May 1995. This short, 20 month cycle time was achieved through careful planning, multi-functional team work and close cooperation between the partners for all critical decisions.

Introduction

Anyone who has examined the equation for net present value understands that minimizing cycle time for developing a hydrocarbon resource is critical. Cycle time appears in the exponent of the discount term; therefore, it significantly impacts the net present value. Anyone who understands the uncertainties in key reservoir parameters such as reserves and productivity, knows that significant time is required to gather and process data to make a rational and optimum economic choice for design capacities of facilities. Balancing these two, seemingly contradictory goals presents a real challenge.

The challenges to develop Simonette, including unitizing, well spacing and scheduling, conserving gas, and selecting the type of flood were identified in a development plan created before discovery. Keys to economic success were also identified in the planning stage, when the discovery was made a multidisciplinary development team was formed. Work began immediately meeting the challenges. Much effort was placed on understanding and meeting the needs of all interested parties including partners and regulatory agencies. Key aspects of effectively and efficiently developing the reservoirs in the short time frame were; maintaining flexibility in depletion and facility designs, timely collection and interpretation of critical information and extensive communication among all people involved in decision making.

In the 20 months between discovery and the start of gas injection in May 1995 accomplishments included drilling 11 development and 2 exploration D&A, wells; producing oil to temporary well site batteries to production test the wells and obtain material balance estimates of OOIP; choosing a depletion strategy of miscible flooding; applying to the Alberta Energy and Utilities Board (AEUB) for flood approval and designing and constructing a facility for 1600m3/day of oil production with expandability to 2300m3/day. Ultimately 21 wells were drilled in the project, three were abandoned. Miscible flood operation continued till April 1996. Gas injection difficulties after a water injection cycle plus the completion of a 110 kilometer gas pipeline led to conversion to a straight water flood in April 1996.

Geology

The Simonette Pools are located about 375km West Northwest of Edmonton, Alberta (Figure 1). Oil is trapped in the Simonette Beaverhill Lake A and B Pools in the updip culmination of a Swan Hills Reef a part of the Beaverhill Lake Group. The Beaverhill Lake Group, illustrated on Figure 2, is comprised of the Swan Hills Formation, consisting of reefal carbonates and the Waterways Formation, composed of basin filling marlstones and carbonate mudstones. The tight marlstones of the Waterways forms the vertical and lateral seal to the northeast of the reservoir, while the southwest seal and bottom seal are provided by tight limestone of the Swan Hills. The A Pool is separated from the B Pool by a normal fault with approximately 30m of throw, shown on the porosity thickness map on Figure 3.

The reefs were deposited in a series of 8 reef stages which grew m response to rising sea levels. These stages, illustrated on Figure 2, were picked using core examination and well log correlations. Development and management of the reservoir is driven by the properties and relationships of these stages to each other; therefore, all wells were cored. Porosities among the stages within a well range from 7% to 12%, while permeabilities could range from 1md to 400md. P. 761