SAGD With a Longer Wellbore

摘要

This paper investigates the feasibility of bitumen production using SAGD technology with a longer wellbore.A longer wellbore can be used to exploit a greater volume of reservoir with a single well as opposed to multiple wells,thus decreasing pad and drilling costs.The major concern of using a longer wellbore from a reservoir engineering point of view is the potentially ununiform steam chamber growth over the whole well length due to pressure drop in the horizontal wells.Reservoir simulation was performed using CMG STARS and Qflow to address the issue.The pressure drop inside the wellbore is calculated using Qflow.Reservoir simulations were performed using STARS.A sectioned model was constructed,dividing the whole length of the horizontal wellbore into multiple sections,each with its own pressure restriction to match the pressure drop obtained from Qflow.The results showed that with sufficiently large wellbore size that resulted in sufficiently low pressure drop,one longer well performed as well as two shorter wells.If the pressure drop in the wellbore is too large by using a smaller size wellbore,the production from a longer well can be significantly impeded.