The application of enhanced oil recovery schemes requires a more complete understanding of reservoirs than that accepted in primary and secondary production practices. Developments in every discipline involved require increased efforts from specialists with different backgroands to express the implications of their respective findings in plain terms.
In this paper, a comparison of three reservoirs is used to illustrate some geometric characters which might be overlooked in reservoir modelling due to the difficulty in expressing them in numbers.
Three Mannville (Lower Cretaceous) sand reservoirs from east central Alberta were selected by the Petroleum Recovery Institute to examine the feasibility of specific EOR processes: Chauvin South Sparky A & B (Polymer), Provost – Upper Mannville B (Steam), and David-Lloydminster A (Polymer), In each case, the project started with a geological study of the reservoir.
The Reservoir Geometry section of each pool study is presented in this paper. Then a comparison is made to emphasize the differences in types of inter-well communication that can be anticipated for these cases.
Geological reservoir studies are becoming increasingly sophisticated, with progress mainly in the fields of reservoir petrology (through the improvement of laboratory techniques) and reservoir geometry (through the investigation of depositional trends). Reservoir and production engineering are relying increasingly on computer science. For reference to these specialized technologies, new terminologies are being created and communications between specialists of disciplines as different from one another as geology and numerical simulation require that these specialists increase their efforts to express, as clearly as possible, the implications of their respective findings.
The description of the geometry of a pool is based on a partly hypothetical interpretation of the geology using scattered well data, It is necessary for a mathematician designing a model of that pool to understand both physical concepts and interpretive uncertainties, so that uncertain parameters can be realistically adjusted in the course of history matching, To illustrate this point, a comparison of three reservoirs described in qualitative terms is used to point out some geometric characters which might otherwise be overlooked in reservoir modelling.
The reservoirs were selected by the Petroleum Recovery Institute1 to examine the feasibility of specific EOR processes: Chauvin South – Sparky A and B (Polymer flooding), Provost – Upper Mannville B (Steam stimulation). and David-Lloydminster A (Polymer flooding). These reservoirs are all located in east central Alberta (Figure 1) and oil is produced from sands belonging to the Hannville Group (Lower Cretaceous) (Figure 2).
This paper is based on n more complete study or the pools described in a report of the Petroleum Recovery Institute 2.
The logs pictured in the illustrations are SP-Resistivity logs, except in cross-sections K-K' (David pool). In order to save space the logs have been juxtaposed in the cross-sections, therefore, the distance between wells is not to scale.
The following description refers to the portion of the Chauvin South oilfield designated as "Sparky A and B Pool" by tile Alberta Energy Resources Conservation Board more specifically to the portion covered by Projects A-12.3l (Unit 1) and A-1317 (Unit 2).