Downhole Packer Seal

A downhole packer seal helps to prevent flow of fluids upstream in the region between pipe and mandrel. The seal along with other components is shown schematically in the figure below. The simplified packer design shows two ring which compress the seal in the confined area. This is a challenging problems as it involves multiple nonlinearities: material, geometric and contact between multiple components and self-contact. As the geometries and loads are axisymmetric, the problem will be analyzed using an axisymmetric model.

The analysis is performed in two steps. In the first step, top ring is moved downwards and in the second step, a fluid pressure is applied.

packer seal

The contour plot of von Mises stresses at different stages  during first step is shown in these figure. The seal is compressed as the top ring moves downward. It fills the space between the pipe and mandrel. During this step, seal experiences contact with all surrounding components and also the self contact. During the compaction, the seal undergoes large strains and rotation. This makes it a difficult problem to solve.

(Note: Click on the figure for closer view)

The contour plot of von Mises stress during second step is shown in these figures. It can be seen as the fluid pressure acts on the seal, it is further compressed. During this step, the seal also separates from the pipe surface as the fluid pressure build up.

(Note: Click on the figure for closer view)

The contour plot of strain at different stages  during first step is shown in the following figure.

The contour plot of strain at different stages  during second step is shown in the following figure. As the fluid pressure increases on the seal, it is pushed upwards and compressed further.

The following animation shows the evolution of von Mises stresses and contact pressure.

Analysis of a downhole packer seal subjected to the pressure of a fluid