Design Methodology of Overshot Inverted Swellable Elastomer Packer

During past 7 years, swellable elastomer technology has been introduced to the oilfield and its acceptance has been so rapid that its scope of application has been rapidly expanded. But throughout this paper, the usage of Swellable Elastomer Packer (SEPs) has been challenged as existing-to-new tubing connector during workover. This project needs to be constructed as such the Inverted SEP manages to handle wellbore parameters from the inside of the tubing itself. Three primary challenges must be addressed when designing SEPs for the above stated applications:
1. The downhole conditions; i.e., the main parameters to which the tool will be subjected such as the downhole pressure increase and the average temperature drop of the sealing elements.
2. Thermal contraction of the sealing element; i.e., contraction that occurs during high rate pumping cooling effect will cause lower anchoring force of the sealing elements.
3. Design concept & workover method; i.e., thorough simulation and discussion on combined technology between Overshot BHA and Swellable Elastomer Packer (SEPs) modified for inward swelling and new tubing latch-on method.
These applications of workover scenario include condemn or damaged of the top subsurface tool (i.e. Surface Control Subsurface Safety Valve SCSSSV and Side Pocket Mandrel SPM). With this new technology – Overshot Inverted Swellpacker, same result with lower operation margin cost can be achieved.
This paper describes the technical challenges and discusses resulting design methodology based on modeling (downhole parameters, anchoring forces, thermal contraction measurements, tool workover simulation and etc.) that have been developed to resolve these issues. This design methodology is not limited to only workover but also applicable to any scenario with dynamic loads on SEP applications such as in high rate injection wells, etc..