REDEVELOPMENT OF THE BRAZEAU RIVER NISKU-A AND NISKU-D VERTICAL MISCIBLE FLOODS WITH HORIZONTAL WELLS

A 400 m long horizontal well was drilled in both the Brazeau River Nis ku A and D pools at a true vertical depth of 3,200 m. Both pools have been under vertical hydrocarbon miscible floods for over ten years. Th e purpose of these horizontal wells was to increase ultimate pool reco very by reducing well drawdown leading to improved GOR behaviour. The location of the horizontal well in the Nisku A pool was selected based on the existing 2-D seismic data in an effort to further exploit the undeveloped portion of the reservoir. Two side track horizontal holes were drilled to search for the porous zone in the bottom of the reserv oir prior to drilling the final horizontal hole approximately 2m above the base of the porous zone. In the Nisku D pool, vertical seismic pr ofiling was conducted to locate the porous zone and to aid in the desi gn of the length, depth and azimuth of the horizontal wellbore. Both w ells were open-hole completed. The initial oil rates were 300 - 400 m( 3)d, and the expected incremental reserves are approximately 300,000 m (3) for the Nisku A pool and 260,000 m(3) for the Nisku D pool, or 4 a nd 10% of their respective OOIP. Because of the relatively high initia l oil rate of the horizontal wells, the high expenditures of $5 millio n for the Nisku A pool and $3.4 million for the Nisku D pool were paid out during the first year of production.