Modeling, Testing, and Case Histories of Swellable Packer Casing Anchoring Performance Enable Wells Destined for Plug and Abandon to Become Producers

Abstract

During the last decade, swellable packer technology has been accepted more readily, and its usage is increasing as a viable method for zonal isolation in the oilfield. During this time, swellable packers have shown a new side to their versatility, as they are now being used in many other applications. These newer applications are requiring that swellable packers provide an anchoring point for the casing or tubing string, and the swellable technology is accepting this challenge by being used to provide this requirement in applications such as casing repair, liner tieback, corroded casing, and multi-stage fracturing.This paper will review case histories and testing in order to illustrate procedures for developing, simulating and validating swellable-packer anchoring forces that will enable swellable packer technology to be applied in new oilfield applications. This testing and information will show that when the application and well conditions are understood, swellable packer technology can be a viable alternative to cementing of casing strings or expandable casing patches for providing anchoring points and isolation. This application often allows larger IDs to be considered and costs of workover operations to be reduced. Critical aspects such as the swelling fluids, pressure requirements, production/stimulation scenarios, well conditions and goals, and other concerns of the engineering and design process will be discussed. The impact of these parameters will be explained as well as how each is important in designing the swellable packer to meet any oilfield application. Other job design aspects such as simulating the swellable packer behavior and performing necessary laboratory testing to validate the simulation will also be compared to case history results.Finally, the paper will conclude how swellable packer technology can be used for many applications requiring anchoring forces. IntroductionSwellable packer technology has been used for a variety of oilfield applications, both on and offshore. Having already proven itself as an effective zonal isolation and pressure containment method for applications such as annular gas migration, water shutoff, and hydraulic fracturing etc., swellable packer technology is being adapted for other oilfield purposes. Many of these new applications require that the swellable packer provide an anchoring point for the tubing or casing string. By using swellable packer technology in new ways, wells that had been destined for plug and abandonment (P&A) have become productive, workover operations have been made easier, and fracturing of wellbores has been made possible in cases previously designated as not feasible.In the following sections, this paper explores the modeling that is required to enable many of these new applications to be performed. Focus will be on modeling software that is available and how meaningful results can be generated from these programs. Additionally, the critical factors that testing has shown to dictate the capability for swellable packers to provide an anch...