Geology of Pembina Field, Alberta

The Pembina field is an excellent example of a stratigraphic trap. The oil occurs at the updip (eastern) termination of sands of the Upper Cretaceous Cardium formation. The area of the field appears to be in excess of 800 square miles. Production is from at least four separate sands and a conglomerate of the Cardium formation. In some areas all of these reservoirs are present one above the other and are separated by shale breaks. As the areal distributions of the various reservoirs do not coincide, the "lean" and "rich" areas in the field can be determined by maps outlining the distribution of the various sand bodies. There are now more than 1,600 producing wells in the field. The daily (prorationed) production is about 106,000 barrels. The total recoverable primary reserve has been estimated to be in excess of one billion barrels. Pembina, situated on a hinge-line, is in an area of multiple stratigraphic traps. Other than from the Cardium, oil and gas have been obtained from the Basal Belly River sands, the Viking sand, a Jurassic sand, and the Mississippian carbonates. All these occurrences are within the limits of the Pembina field and all are stratigraphic traps. The reservoirs in these formations have not been evaluated to any extent at present. These reserves will probably not equal those of the Cardium but they will be of very considerable size.