Only a few recent thermal projects targeting the extensive heavy oil and bitumen deposits in Alberta and Saskatchewan have been technical successes, and even fewer yielded acceptable economics. One cause appears to be an engineering approach which neglects existing geologic data, and resists collection of additional data.
When incorrect reservoir models are adopted, most tasks initiated to improve project performance are severely impeded. For example, lab tests and conceptual and numerical modelling predictions are often misdirected to solve the wrong problems. Studies done in-house, by universities, and at government facilities are affected.
Technical contributions from this paper are: (1) Recognition that you cannot force a reservoir to respond in agreement with a preconceived simplistic descriptive model, (2) Enhanced awareness of the level of knowledge required to adequately describe reservoirs being considered for thermal EOR projects, or to better understand the performance of existing projects, and (3) Recommendations for obtaining the information required to better describe reservoirs during the current challenging economic environment.
Numerous Alberta and Saskatchewan thermal EOR field projects were initiated during the early 19BO's, but few survived the oil price drops of the mid-to late 1980's. Many workers were removed from this technical area without an opportunity to document their theories regarding possible technical and economic improvements, The large volumes of heavy oil and bitumen in place, but not yet economic, merit more documentation, and one objective of this paper is to stimulate interest in this task.
It is the author's opinion that the two major causes of project failure were: inadequate understanding of the geologic features of the reservoir, and hesitancy to take the steps required to obtain the information required to remedy the problem.
Recent technical literature describes methods of greatly enhancing understanding of reservoir geology (for example, see Hong(1), Chopra(2), Olea(3), and Dusseault(4)). However, these methods appear to be economically impractical for Western Canadian heavy oil and bitumen reservoirs, which are thin in areas such as Lloydminster (Figure 1) and produce low priced liquids. If the reservoir is owned by a small oil company, with limited operating capital, cost limitations would be even more restrictive.
Who Says Predicting Reservoir Geology is a Problem?
Most articles or papers discussing Western Canadian thermal field projects contain statements about the detrimental affect of unexpected geologic features. Recent examples are. AOSTRA's book summarizing their first 15 years of operation(5), and recent articles discussing Shell's Peace River project(6), the Ipiatic Heavy Oil pilot(7), and Imperial's Cold Lake project(8).
Perhaps some solace can be obtained from a recent statement by SPE President Jaques Bosio that one of the primary reasons EaR projects fail is "... the lack of knowledge of our reservoirs (heterogeneity) ...."(9), and from learning that geologic surprises are also encountered in Venezuela(10). .
Why Wasn't Reservoir Geology Adequately Described Initially?
In selected cases it probably was. Some reservoirs were apparently deposited uniformly, and require less information to develop an accurate description. And, major oil companies had the capital to dedicate geologists