Lessons Learned from Water Shut-off of Horizontal Wells Using Inflatable Packers and Water Shut-off Chemicals in the Ghawar Field of Saudi Arabia

Due to the advancement of technology and improved capabilities of drilling horizontal wells, producers and injectors are now commonly completed with long horizontals to expose large reservoir areas. For the reservoir pressure maintenance, the most prevalent means is by using water injection. This injected water, while helping in pressurizing the reservoir, becomes a curse when it starts to produce with the oil. In addition, as the transmissibility of the water is higher than the oil, water breakthrough is a major challenge facing the oil industry. Various techniques are available and being used worldwide to control/reduce this produced water; however, controlling water production by performing water shut-off (WSO) in horizontal wells is more complicated and challenging than in vertical wells. To control water production in horizontal wells, isolation of the wellbore using inflatable packers in open/cased hole completion and capping with cement has shown little success in the past. Therefore, another technique was attempted to control water production in horizontal oil producers by using mechanical means to isolate the wellbore and chemical means to isolate the matrix/fissure, which forms a permanent barrier and reduces water production. The selection criterion for mechanical isolation and type of chemical suitable for the formation is a tedious task for the petroleum engineer. Most of the time, the vendor’s data that is available is being used and applied for the field application, which shows a low success ratio. In this paper a brief overview has been presented, taking into account two wells from Ghawar field in Saudi Arabia, where a combination of wellbore isolation using inflatable packers and matrix/fissure isolation using an organically cross-linked polymer (OCP) system were performed. The candidate selection criteria, job criteria, planning, execution, and post-job evaluation will be discussed.