Numerical approach to simulate placement of wellbore plugging materials using the Lattice Boltzmann method

Abstract

An approach is introduced using the multi-component lattice Boltzmann method (LBM) to numerically simulate multi-layered wellbore plug placement and investigate the effects of the rheological and physical properties of cement slurry and bentonite clay gel as plugging materials. As a proof of concept, this approach is applied to simulate the placement of a layer of cement slurry within a layer of bentonite clay gel to form three distinct alternating material layers in a wellbore. Prior to investigating this system, the LBM approach is validated through physical lab-scale plug placement tests. Then, a computational field-scale case study is examined to evaluate how variations in plug material properties and placement processes affect the resulting multi-layered wellbore plug. The analyses show that cement slurry density is the property that most affects the wellbore plugging process. At lower concentrations of bentonite clay gel, more cement slurry is needed to create the three-layer system, since the cement slurry penetrates further into the bentonite clay gel. Alternatively, for high concentrations of bentonite clay gel, higher density cement slurry can be placed as a distinct layer without having a significant increase in the amount of cement slurry needing to be pumped. For the cases considered, variations in yield stress and viscosity of the cement slurry have negligible effects on the plugging process. Lastly, although the pumping velocity controls the rate of cement slurry layer placement, it has a relatively small effect on the placement process. Overall, the LBM approach is shown to be an effective method to evaluate wellbore multi-layered plugging processes.