Abstract

A sandstone reservoir (SA) is the main producer reservoir in offshore Khafji oil field. This field has been producing since 1959. However, for time being, some wells suffer from excessive water production especially in old vertical wells. In addition, early water breakthrough in vertical wells is mainly due to high permeability streaks and unfavorable mobility ratio.

Therefore, controlling water production is a challenge for reservoir management team work in Khafji Joint Operations (KJO) because there are several different explanations for the water sources in SA sandstone reservoir. These sources could be one or combination of edge water movement and flow behind casing. This phenomena can occur due to high permeability streaks, and conductive channels or/and faults.

To sustain the KJO Maximum Sustainable Capacity (MSC), reservoir management in KJO should apply optimum development scenarios for reducing the water production utilizing several and effective water shut-off techniques due to production facility bottlenecks. Converting the old and high water production vertical wells to horizontal and lateral wells which have shown a high rate of success in terms of conducting better technique and scenario to retrieve and bring these wells into production with low water cut. The approaches included also reducing the choke size, cement jobs to shut-in watered out intervals and adding new perforations or re-perforating oil productive intervals. Several successful field cases have been applied in SA reservoir which resulted to high oil production with low water cut. This paper discussed more details of lessons learned and applied techniques to control excessive water production from oil wells and comparison in selecting them for applying optimum applicable techniques.

The results of water management techniques and scenarios to retrieve the wells are analyzed and discussed in this study. Reasons for conversion, directions, diagnosis, selected intervals, simulation results analysis, lessons learned, challenges and conclusions were addressed in this paper.

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