The two-phase coning model of Settari and Aziz is used to predict the coningphenomena for two well in the Sylvan Lake, Pekisko B Pool, and the results arecompared with available history. Accurate and detailed information provided bythis model is used to explain some interesting aspects of the coning problem. The predicted results for suitably adjusted reservoir parameters are in goodagreement with field history even for a case where abrupt changes in productionrate occur. The reservoir parameters investigated here are: horizontalpermeability, vertical permeability near the well bore, and pressuremaintenance by water or oil influx.


Water coning into oil wells can affect adversely the performance of the well. Therefore, it is imperative to understand and be able to predict the influenceof the coning phenomenon on field performance. Also, by understanding cheformation and behavior of the cone, it may be possible to develop productionschemes which will counteract the influence of the cone.

The most powerful tool for a full understanding of the coning phenomena is aproperly designed numerical model which solves the relevant partialdifferential equations on a digital computer. One such model has been developedat The University of Calgary. By a proper use of a computer model one mayinvestigate the influence of various reservoir and fluid properties, completionschemes and production schemes on the water-oil ratio. In this paper we presentresults of some studies of this type. Two wells, No. 4–15 and 10–16 in the Sylvan Lake Pekisko B pool were selected for this investigation. Goodproduction history is available for these wells and they are typical ofdifficult-to-model wells often encountered. Before going into a description ofthe reservoir and the wells we mention some unique features of the computermodel used.

Coning Model Used

Some aspects or this model are discussed in a recent paper by Settari and Aziz1. The model so1ves simultaneously the partial differentialequations for pressures in each phase by finite-difference methods. The modeldiffers from other published schemes in several important aspects:

  1. The grid-point distribution method is used2. This method placesgrid points at reservoir boundaries and block boundaries are determined by

Equations (available in full paper)

  1. The reservoir-well bore interaction is carefully considered in this comingmodel. This is done by (a) satisfying the condition that capillary plessuremust go to zero in the well bore, and (b) the pressure gradient in the wellbore must be compatible with the pressure gradient at the sandface. These twoseemingly obvious conditions have been treated properly for the first time by Setiari and Aziz 1. In addition to giving accurate results evenclose to the well bore, these conditions greatly improve the stability of thecoming model.

  2. A new approach is used Ear the treatment of Borne nonlinear terms in thismodel. In particular, this approach eliminates the necessity to literate e inorder to obtain good material balance.

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