One of the common applications of horizontal wells is the development of thin oil columns underlain by bottom water and/or overlain by a gas cap. Vertical wells are not suited in this situation due to the rapid coning of water or gas at reasonable production rates. Horizontal wells correctly positioned in the oil column, however, can produce at high flow rates with very little drawdown. The small drawdown significantly delays the breakthrough of water or gas at flow rates much higher than the flow rates possible from a vertical well.

The flow distribution in a horizontal well designed to develop a thin oil column can be significantly impacted by friction losses in the wellbore. The impact of friction results in a higher drawdown at the heel as compared to the toe of the horizontal well. While this impact is insignificant in lower permeability systems, it can lead to premature water or gas breakthrough at the heel of the well in high permeability systems produced with low reservoir drawdown.

Skin damage is normally undesirable due to its detrimental impact on well productivity. In high permeability systems developed with horizontal wells, however, well productivity is normally not a problem. Skin damage actually diminishes the detrimental impact of friction in horizontal wells by improving the flow distribution. This study investigates the intentional inclusion of mechanical skin damage in a high permeability, North Sea horizontal development. Reservoir simulation was used to justify and design a limited entry completion that was shown to improve flow distribution and oil recovery, at a significantly lower completion cost. The desired uniform flow rate distribution was confirmed by a PLT run in the first well, and through reservoir simulation and history matching.

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