Production Experience From Smart Wells in the Oseberg Field

Abstract

Abstract The Oseberg Field is located offshore Norway 140 km Northwest of Bergen at approximately 100m waterdepth. Including the recently installed Oseberg D gas platform, the field is developed with four offshore installations. The expected reserves estimate is 336 MSm3 of which 266 MSm3 has been produced by January 2000. Pressure maintenance is implemented by re-injection of associated gas and import of gas from the nearby Troll Field. In addition water injection takes place in some parts of the field. Oseberg is by May 2000 producing approximately 46000 Sm3/d (290000 stb/d) from 42 production wells. Plateau oil production of 81000 Sm3/d (510000 stb/d) ended in 1997. The initial 200m oil column has been reduced to an oil rim of 20-40m as more than 75 percent of the reserves have been produced. Most producers have experienced gas break through and oil production is now limited by gas handling capacity. The use of smart wells enables remote control of zones with excessive gas production. In the Oseberg Field, such completions have so far been installed in four wells. In the first well one ‘smart’ completion was installed in combination with mechanical sliding sleeves in two other zones. The primary objective was to verify the robustness of the equipment at downhole conditions of the Oseberg field. In the second well four zones with this completion was installed in a channel sand deposit. Rapid gas break through at the heel of the horizontal section was choked remotely, resulting in a reduced GOR and improved oil production rate. The third well with four zones was installed in a more homogenous formation. Communication was lost with three of the four zones after 40 days production. Production from the fourth well commenced in august 1999. Technical operations of the three zones were ok, but the well was experiencing production problems in the beginning due to poor pressure support and lifting problems.