(493f) Reverse-Circulation Cementing of Offshore Hydrocarbon Wells: A Simulation Study

In deepwater, offshore wells, the primary cementing process is often complicated by low formation fracture pressures, high risk of lost circulation, and high equivalent circulating densities, making zonal isolation difficult or impossible. In response, reverse-circulation primary cementing (RCPC) is being explored as a means of overcoming these challenges. In RCPC, fluids are pumped downhole through the annulus, and then up into the casing, in contrast to a conventional cementing process where fluids are pumped down the casing and up into the annulus. This technique has been used in rare cases and has proven effective at lowing equivalent circulating densities.

In any cementing process, it is important to consider the temperature gradients and ECDs the cement will experience in order to determine which retarding additives need to be added to the slurry so that the slurry does not set early. The cementing job must be modeled in order to determine these parameters in advance. While many software packages exist to model conventional cementing jobs, due to the specific nature of reverse circulation cementing, they are unable to properly model the cementing process. The COMSOL Multiphysics finite-element software package has therefore been used to develop a robust model capable of handling the reverse-circulation cementing process.  Current results will be presented and discussed.