Synopsis I

We are able directly to determine the actual water content of oil sand samples taken from mines. Capillary pressure tests conducted for the sake of comparison in order to find the irreducible interstitial water content, have yielded values being twice or thrice as high. This leads to the conclusion that the widely-used capillary pressure method is probably unable to reproduce a reduction of the water content to the same degree as might be attained in nature in the course of geological ages. This conclusion, which is being confirmed by direct geological observations and considerations is of the utmost practical importance, insofar as it will change not only the reserve estimates but also the probable recovery fator. The exact definition of the connate water concept at its lower limit is thereby also changed and complicated.

Résumé

Nous avons la possibilité de déterminer directement la saturation réelle en eau des échantillons de sable pétrolifère provenant de min es.

Des tests de pression capillaire exécutés à fin de comparaison pour mesurer la saturation irréductible d'eau interstitielle ont fourni des valeurs deux ou trois fois plus grandes.

Ceci mène à la conclusion que la méthode largement utilisée de la pression capillaire est probablement incapable de reproduire une réduction de la saturation en eau aussi poussée que celle qui est atteinte par la nature au cours des âges géologiques.

Cette conclusion qui est confirmée par des observations et considérations géologiques directes est de la plus haute importance pratique, du fait qu'elle doit changer non seulement l'estimation des réserves mais aussi le facteur de récupération probable.

La définition exacte de la notion d'eau connée à sa limite inférieure est également modifiée de ce fait et rendue plus compliquée. * Geologist "Deutsche Erdoel-Aktiengesellschaft", Wietze, Germany.

RUEHL * I-Problem Numerous research men have been engaged in studying the problem of the water contained in the pore spaces of a reservoir rock, which is of importance not only with regard to the calculation of the reserves but also to the flow processes involved and to the mechanism of drainage as well as to the degree 04 depletion.

In order to answer these questions, we shall primarily concern ourselves with the interstitial water which is found in the field when oil production is started and which represents a more or less "fixed", i.e. immovable component of the pore spaces. (Subsequent stages of water encroachment surpassing the critical water saturation will not be discussed in the paper in hand.) It is of secondary importance only, whether the water is of primary origin, i.e. deposited by sedimentation as connate water, or of secondary origin, i.e. migrated into the formations in the course of geological ages. Normally, connate water will have been disp

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