SAGD process with the combination of vertical and horizontal wells in super-heavy oil reservoir

Xinglongtai Formation in Block Du 84 of the Shu1 heavy oil area,Liaohe Oilfield,is a massive-block extra-heavy oil reservoir,with the oil viscosity greater than 100Pa·s at 50℃.This paper presents the feasibility of SAGD process with the combination of vertical and horizontal wells based on the reservoir characteristics,oil properties and development status.Well patterns are investigated using numerical simulation,and the parameters of injection and production are optimized after several cycles of steam stimulation with the formation pressure greatly reduced.The SAGD process is viable and the recovery factor is increased by 30.0% with the cumulative oil steam ratio of 0.296.The optimum well pattern is that horizontal wells with 20m apart are drilled between and beneath two rows of vertical wells.The horizontal well length is 280m.The steam quality at down-holes must be greater than 70% and the drawdown capacity in production wells have to be matched with the injection rate in injection wells.