Reservoir Surveillance Program: Judy Creek Beaverhill Lake “A ” Pool Hydrocarbon Miscible Flood
Authors: Jonasson H.P. 
Published: March 2010

Abstract
In May 1985, Esso Resources Canada Limited commenced hydrocarbon solvent injection into the Judy Creek Beaverhill Lake "A "Pool. This staged miscible flood is forecasted to recover an incremental 6% of the original oil-in-place.
To ensure maximum tertiary oil recovery, Esso Resources has initiated a thorough reservoir surveillance program. The program includes a computer system to monitor production, injection, and voidage data, a radioactive tracer program to track solvent and water flow, injection and production logs to monitor the zonal distribution of the injected solvent, reservoir pressure surveys to ensure solvent/oil miscibility and solvent containment, solvent injection composition monitoring, and a sampling program to monitor reproduced fluid compositions.
This paper discusses each of these reservoir surveillance tools and how the results are being used to optimize the hydrocarbon miscible flood in the Judy Creek Beaverhill Lake "A "Pool.

Introduction
The Judy Creek Beaverhill Lake "A" Pool, located 200 km northwest of Edmonton, was discovered in 1959 and has an areal extent of approximately 115 km2 (Fig. 1). Figure 2 illustrates a structural cross section of the pool. The pool is an atoll-like reefal limestone complex of Upper Devonian age. The reef is up to 67 m thick and is situated on an a really more extensive limestone platform which is about 40 m thick. Together, the reef and platform limestones comprise the Swan Hills Formation of the Beaverhill Lake Group.
The original oil-in-place (OOIP) has been established at 130.4 × 106 m3 and a recent decline analysis by Esso Resources(1) indicates a waterflood recovery of 49.3 × 106m3 or 37.8% of the OOIP. In February 1983, Esso Resources submitted an application(2) to the Energy Resources Conservation Board (ERCB) for approval of a hydrocarbon miscible flood for the Judy Creek Beaverhill Lake "A" Pool. In this application, Esso Resources forecasted that the hydrocarbon miscible flood would result in an incremental oil recovery of 7.8 × 106m3 or 6% of the OOIP.
FIGURE 1. Swan Hills Formation. (Available in full paper)
Approval for the hydrocarbon miscible flood was granted by the ERCB in October 1983 and solvent injection commenced in four northeast patterns in May 1985, in ten southwest patterns in July 1985, and a further two southwest patterns in October 1985. Figure 3 outlines the miscible patterns in the Judy Creek Beaverhill Lake "A" Pool. A thorough reservoir surveillance program is critical to the success of the miscible flood. The reservoir performance aspects of areal and volumetric sweep efficiency, oil/solvent miscibility, and tertiary oil production need to be maximized to offset the initial capital cost of the project and the continuing injectant cost.

Reservoir Surveillance Tools
Automated Reservoir Management System (ARMS)
In 1984, a feasibility study was undertaken to identify the computer systems which would have to be developed to handle the volume and complexity of data associated with a miscible flood.
FIGURE 2. Judy Creek Beaverhill Lake "A" Pool structural cross section. (Available in full paper)
TABLE 1. Automated reservoir management system-Judy Creek Beaverhill Lake "A" Pool. (Available in full paper)