fax 01-972-952-9435. AbstractHorizontal wells have become very common in the Middle East because of their capability to increase reservoir contact, particularly in carbonate reservoirs. These types of formations often are naturally fractured, and because of channeling from underlying aquifers, allow the ingress of water into the production process systems. When water breaks through to the well completion, it tends to increase and becomes preferentially produced, thereby reducing the volume of produced hydrocarbons. This phenomenon adds cost to the well operation because of the requirement to lift, separate, treat and dispose of the water. Preventing and managing water-cut through cementing, chemical application or the use of mechanical openhole barriers such as inflatable packers is costly, and often, the method chosen is not effective. This paper will discuss the use of swellable packers to provide a long-term, completely effective, water shutoff tool. These packers use expanding rubber around the packer that expands to seal the annulus. When expanded, a permanent seal is created, regardless of whether the packer has been run as a straddle or as a plug. The packers can be used in open and cased-hole applications in all the most common oil-and gas-well environments.This paper discusses the development and design of the packer and presents case histories from the Middle East and other parts of the world that illustrate the advantages that swellable packer technology can provide to operators in reservoirs in which water break-through has been predicted or experienced.In these case histories, it will be shown that the packers significantly reduced water cut, which in turn, reduced water disposal costs and intervention needs while increasing production rates and extending field life.

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Horizontal wells have become very common in the Middle East because of their capability to increase reservoir contact, particularly in carbonate reservoirs. These types of formations often are naturally fractured, and because of channeling from underlying aquifers, allow the ingress of water into the production process systems. When water breaks through to the well completion, it tends to increase and becomes preferentially produced, thereby reducing the volume of produced hydrocarbons. This phenomenon adds cost to the well operation because of the requirement to lift, separate, treat and dispose of the water. Preventing and managing water-cut through cementing, chemical application or the use of mechanical openhole barriers such as inflatable packers is costly, and often, the method chosen is not effective. This paper will discuss the use of swellable packers to provide a long-term, completely effective, water shutoff tool. These packers use expanding rubber around the packer that expands to seal the annulus. When expanded, a permanent seal is created, regardless of whether the packer has been run as a straddle or as a plug. The packers can be used in open and cased-hole applications in all the most common oil- and gas-well environments. This paper discusses the development and design of the packer and presents case histories from the Middle East and other parts of the world that illustrate the advantages that swellable packer technology can provide to operators in reservoirs in which water break-through has been predicted or experienced. In these case histories, it will be shown that the packers significantly reduced water cut, which in turn, reduced water disposal costs and intervention needs while increasing production rates and extending field life. Reservoir Challenges Major oil companies worldwide continue to evaluate new technologies to ensure that their strategic resources are optimally explored, developed, and efficiently produced during the life of their oil and gas fields. Abu Dhabi National Oil Company (ADNOC) along with its group of subsidiary companies are among the companies that continue to pursue innovative technologies. The actual adopting of a new technology varies considerably between different operating companies with the early adopters being more willing to take risks if it means that the investigated methodologies could prove to offer greater advantages to production scenarios. Since the swellable packer has shown success in many different applications, its acceptance has been accelerated. The exponential growth in usage of the swellable packer is shown in Figure 1. Management of produced water has been a major challenge in the ADNOC and other operator wells in much of the Middle Eastern area. Water cut in new and existing production wells is undesirable, and in many cases, leads to increased operating costs to dispose of the water, expensive remedial treatments, environmental issues related to disposal, and the premature shut in of the wells. This often leaves oil in place that may never be produced. In the last twenty years, step changes in the capability to deliver accurately placed long horizontals have proven extremely beneficial to many operators of carbonate reservoirs worldwide. Natural and drilling-based faulting and fractures in these formations are relatively common, and water from other nearby formations will use these channels to break through to the production string, significantly reducing oil production. Operators worldwide have used multiple technologies to try strategies that can combat "bad" water; i.e., water that does not add to net oil produced. Chemical methods have proven effective in targeting longer sections where the gels and polymers can be placed deeper into the formations. Fractures and faults typically have been targeted with mechanical isolation methods such as bridge plugs and inflatable packers. This paper discusses a newly developed technology, swellable packers, and uses case histories from the Middle East and other regions to describe their use to improve the reliability and deployment of mechanical water shutoff methods.