Open File Report 1968-06

Open File Report 1968-06

OFR 1968-06

Memo on the Effect of the Sump on the Dewatering of the Overburden in G.C.O.S. Lease 86

Author(s) Research Council of AlbertaKahil, A. Date 1968-07-03

The purpose of this memo is to evaluate the effect of the sump being dug on the Great Canadian Oil Sands Lease 86 for the purpose of dewatering the overburden. The sump at the present is being pumped at a rate averaging approximately 1.36 million gallons a day for the week of June 16 to 22. It should be emphasized at the outset that due to the short period of time in which I have been studying the ground water in the overburden, any conclusions arrived at in this memo should be considered as opinions which are not based on sufficient information and which will probably be revised at a later date.

The only records in the effect of the sump on the ground water in the overburden is provided by thirteen observation wells, two of which have been destroyed before this date. As of June 15 the following observation wells have recorded the effect of the sump by a drop in the water level in these: P1, P4, P8, P11, P14, P15, CH 117 and CH 122. The other observation wells do not appear to be affected by the sump (included in memo). The approximate border of the cone of depression produced by the sump is shown. It is in the shape of an ellipse with the long axis oriented in a southwest-northeast direction. One factor that controls the shape of a cone of depression is the relative permeability of an aquifer. If this is the cause of the elongated cone of depression in the overburden, it would mean that the permeability of the overburden is greater in a southwest-northeast direction in the vicinity of the sump. The shape of the cone of depression coincides with the A1 and B1 sand deposits (fig. 14, 15 and 16) as mapped by Linkens (1965). These sands are reported to have a permeability between>50 and 1 x 10-5 ft/year by Materials Testing Laboratories as compared with the overlying BII, AII sand which have a reported permeability ranging between 0.2 and 50 ft/year. Thus it seems probable that the elongation of the cone of depression is caused by the greater permeability of the AI and BI sands.