A Simplistic Evaluation of Over 30 Years' Horizontal Hydrocarbon Solvent Flood Performance In Alberta
Authors: Randall Tom 
Published: March 2010

The following discussion will examine the trends in performance shown by mature projects in an attempt to expose reasons for encouraging/discouraging results. Inferences drawn from the information presented are those of the author. The reader is left with the responsibility of building them into useful conclusions.

Data Resources

Bias in the interpretation of the performance of the 10 project areas studied was avoided by limiting the data used to Alberta Energy Resources Conservation Board (AERCB) records:Defined project areas and the wells within themAverage reservoir factors and discovery datesInitial oil in placeProduction and injection history filesExecutive summaries and maps in operations reports

The parameters used in relation to the performance analysis are presented in Table I.

Analysis Concepts

As a start, a small set of key performance measuring parameters was sought. After examining alternatives oil rate performance was perceived to be the most useful parameter, particularly with regard to establishment of stable decline to ultimate recovery and reaction to changes in reservoir depletion process. Producing water-oil and gas-oil ratios were included, indicating ability to keep injected fluid in the reservoir and success of management strategies. Total liquid production completes the set used giving information about reflection of wells to changes in reservoir depletion process and operations aimed at reducing production of injected fluids.

The selection of study variables immediately led into a "decline curve" approach, so that plots against a reservoir dependent parameter could be extrapolated to yield inferences about future performance and ultimate expectations. Cumulative oil production since discovery was selected as a common yardstick, to avoid the impact of difference in reservoir quality and depletion rate strategies.

Cumulative oil production was divided by rated initial oil in place, and became "depletion", plotting between 0.0 and 1.0.

Oil and total liquid production rates were divided by the peak value attained, plotting between 0.0 and 1.0. Producing gas-oil ratio was divided by initial solution gas-oil ratio, plotting between 1 and the chosen practical or "economic" limit of 15. Water-oil ratio is already normalized, plotting between 0.0 and the chosen practical or "'economic" limit of 20.

Space does not permit printing the entire set of performance plots developed. Their salient features are discussed below, and the slopes for the straight line extrapolations are presented in Table 2. Capability to re-create the plots from the public data is within reach of anyone desiring to do so.

The plots for Fenn-Big Valley South Lobe Project 338 and Kaybob South Triassic "A" Project 165 are presented as Figures 1–4 to show favorable and unfavorable changes in reservoir behavior resulting from horizontal solvent flood.

Project Performance Reviews

The projects are presented in alphabetical order by pool name to avoid ordering bias. Wherever practical, more than one parameter is extrapolated to show the range of possible outcomes for a project.

Ante Creek Project 2

The Ante Creek Beaverhill Lake "A" Pool carbonate reef was discovered in 1962. The location was remote from gas processing and transportation facilities.