For decades it has been known that there are several techniques for heavy oil recovery, including traditional Steam Assisted Gravity Drainage (SAGD), cross-well SAGD, single well SAGD, and horizontal alternate steam drive (HASD) etc. The main purpose for these techniques are incresasing efficiency of the SAGD process and controlling steam chamber development.
In this paper, case history will be shared in regards to, implementing for the first time a new method of SAGD techniues in the Alshachinskoe heavy oil field. Based on the results of several trial wells, the proposed dual wellheads SAGD scheme provides the following advantages over traditional SAGD: (1) less risk during drilling and completion phase, (2) more uniform preheating phase provided by several injection points, and (3) more possibility for steam chamber development control during production phase.
As a result the average production for heavy oil was increased from 2 tonnes per day for vertical wells to 24 tonnes per day for dual wellheads SAGD technology (with maximum daily production up to 63 tonnes). The average steam-oil-ratio for dual wellheads SAGD is around 3 (sm3/sm3), that proves high efficiency of the method for steam chamber development and steam trap control over entire period of wells life time.