Swellable elastomeric seals (packers) have been widely employed in various oil-&-gas and minerals applications. Examples include slimming of well design, zonal isolation, water shut-off, and multi-stage fracturing. Important characteristics of packers required for these applications are how fast the packer can seal the borehole as well as how fast a certain amount of contact pressure can build up. These characteristics, which are generally measured from full-scale packer tests, can be predicted through numerical FEM simulations (using ABAQUS, ANSYS, MSC.Marc etc.) based on material data obtained from basic experiments. The key component of numerical prediction is an availability of advanced material models for swellable elastomers, which would be capable of accurate simulation of packers’ non-linear mechanical behaviour under various downhole conditions. The numerical simulation of packers can be incorporated into optimisation procedure finding an optimal shape of packers with the goals to minimise the time to seal the borehole and maximise the contact pressure between the seal and borehole. Such an optimisation procedure would allow the Weir Group to produce the packer with various designs optimised for different downhole conditions considering the borehole type, i.e., permeable or non-permeable borehole, and downhole uncertainties, i.e., variations of borehole size and borehole temperature. Through this research project, we hope to develop an optimisation procedure based on advanced FEM simulation to provide us an improved design of packers produced by Weir Minerals USA and design recommendations for various downhole conditions.
1. Design and manufacturing of tools for mechanical testing of swellable elastomeric specimens and mechanical behaviour of packers in conditions resembling downhole operation.
2. Mechanical characterisation of swellable elastomers used by Weir Minerals USA for packers through experimental studies in Advanced Materials Research Laboratory (AMRL) in the University of Strathclyde (https://www.strath.ac.uk/amrl/)
3. Implementation of an advanced material model in FE-code and identification of corresponding material constants for it.
4. Development of an optimisation procedure for available FEA packages (ABAQUS, ANSYS, MSC.Marc etc.) based on packers behaviour simulation using an advanced material model.
5. Optimised packers geometry is obtained by running the optimisation studies on the regional supercomputer centre at the University of Strathclyde – ARCHIE-WeSt (https://www.archie-west.ac.uk/).
6. Provision of packers design recommendations and optimal designs based on a number of optimisation studies for variety of downhole conditions in form of tables and/or mathematical relations.