After 3 years of production, 4d seismic, and production logging analysis, completion strategy was reevaluated. For more effective drainage of the multilayered reservoir, oil wells have become smart, and water injectors have become conventional single zone wells. Already drilled oil wells were worked over and new completion string incorporating 140 mm (5.5”) tubing with up to six zonal isolation packers, pressure-temperature gauges, surface-controlled downhole flow-control valves was installed.
The results are encouraging: high GOR zone were choked and lower kh/pressure zones were allowed to contribute to production which stabilized around 1000 m3 (6000 bbls) of oil per day. However, some cases were more complicated, and those lessons learned were incorporated into new wells design.
Lunskoye gas field has super big bore gas wells with 244 mm (9-5/8”) production tubing delivering 10 mln m3 of gas a day (300 mmscfd). Oil rim is being developed with long horizontal smart completion. The wells penetrate gas reservoir with 244 mm (9-5/8”) liner and can be turned into super big bore gas well in the future. Gas zone is used for the controlled natural gas lift.
These world class completions are installed at a remote offshore location in sub-Arctic environment by the relatively young crews mostly consisting of Russian nationals.
About the Author
Kirill Bogachev is a Completion Supervisor at Sakhalin Energy. His main responsibility is to supervise execution of completion and well intervention programs at an offshore platform. Routine Sakhalin Energy completions and well interventions include surface-controlled smart wells, 9-5/8” (244 mm) super big-bore gas wells, wells with hundreds of meters of perforation intervals, various interventions and workovers on high-rate oil wells.
Prior to Sakhalin Energy Kirill worked for BP America as a completion engineer, designing completions and well interventions for Tight-gas, Coalbed methane and Shale gas wells onshore US.
Kirill holds MS degree in Petroleum Engineering from Texas A&M University and BS degree in Petroleum Engineering from Gubkin Russian State University of Oil and Gas.