Khafji offshore field, located in the Arabian Gulf, contains an unconsolidated sand reservoir subdivided into two, upper and lower reservoirs. Upper sandstone reservoir has relatively low reservoir pressure utilizing gas lift to help wells achieve production target rate. The main obstacle in upper reservoir is water encroachment due to unfavorably high-water mobility compared to oil; which presents a reservoir management challenge in the form of curbing water production linked to relatively high-permeability sandstone reservoir. In upper reservoir, water encroachment is dominated by active edge-water drive and it has irregular water-front movement because of the presence of high permeability streaks.
Excessive water production from the high permeability upper sandstone reservoirs causes major economic, operational, and environmental problems during oilfield operations. Water production can also cause secondary problems such as sand production, corrosion, emulsion, and scale formation. Although the reservoir has been on production more than 50 years, water sources are still considered to be a mystery. Many different concepts and scenarios have been considered such as channeling behind the casing, highly conductive faults, channeling through the high-permeability zones and high-permeability streaks, which accelerated water production. As a result of this issue, water breakthrough at crested wells in an edge-water driven upper reservoir and water production has increased.
Inflow Control Devices (ICD) completion has been installed in upper reservoir wells to overcome water production challenges. Low reservoir pressure is a major challenge for upper reservoir wells ICD completion design. During the course of this paper, Khafji field water encroachment study results have been discussed to show the latest water front movement expected scenario. In addition, ICD-completed wells performance was analyzed and compared to cemented perforated liner completion wells (Non-ICD completion) offset wells in upper reservoir. The parameters that were used during the ICD-completion design to overcome the main field challenges were highlighted. ICD completed wells showed positive performance results in water production control and higher oil production rate.