Thermal oil recovery with horizontal wells

This paper reports on horizontal-well technology which is now being used in EOR projects, especially in thermal oil recovery. Although horizontal wells have recently been used in miscible and waterflood projects, the main EOR applications to date are in steam projects. Several horizontal wells have been drilled as pilot projects for thermal oil recovery in bitumen and heavy-oil reservoirs. A few field pilots show commercial viability. Thermal oil recovery is used to produce heavy oil or bitumen in high- permeability reservoirs. The main advantages of the use of horizontal wells are improved sweep efficiency, enhanced producible reserves, increased steam injectivity, and a decrease in the number of wells required for field development. This last point is especially important in thermal oil recovery projects, where several closely spaced vertical wells are required for economic development. A 2,000 - 4,000-ft-long horizontal well can replace several vertical wells, reducing investment and operational costs. The main disadvantage of horizontal wells is their initial cost.