Modeling Diffusion and Buoyancy-Driven Convection with Application to Geological CO₂ Storage

الموضوعات

علوم بحتة وطبيعية

الملخص

Modeling Diffusion and Buoyancy-Driven Convection withApplication to Geological CO2 StorageRebecca AllenGeological CO2 storage is an engineering feat that has been undertaken around the world for more than two decades, thus accurate modeling of flow and transport behavior is of practical importance. Diffusive and convective transport are relevant processes for buoyancy-driven convection of CO2 into underlying fluid, a scenario that has received the attention of numerous modeling studies. While most studies focus on Darcy-scale modeling of this scenario, relatively little work exists at the pore-scale. In this work, properties evaluated at the pore-scale are used to investigate the transport behavior modeled at the Darcy-scale. We compute permeability and two different forms of tortuosity, namely hydraulic and diffusive. By generating various pore ge- ometries, we find hydraulic and diffusive tortuosity can be quantitatively different in the same pore geometry by up to a factor of ten. As such, we emphasize that these tortuosities should not be used interchangeably. We find pore geometries that are characterized by anisotropic permeability can also exhibit anisotropic diffusive tortuosity. This finding has important implications for buoyancy-driven convection modeling; when representing the geological formation with an anisotropic permeabil- ity, it is more realistic to also account for an anisotropic diffusivity. By implementing a non-dimensional model that includes both a vertically and horizontally orientated5Rayleigh number, we interpret our findings according to the combined effect of theanisotropy from permeability and diffusive tortuosity. In particular, we observe the Rayleigh ratio may either dampen or enhance the diffusing front, and our simulation data is used to express the time of convective onset as a function of the Rayleigh ratio. Also, we implement a lattice Boltzmann model for thermal convective flows, which we treat as an analog for CO2 storage modeling. Our model contains the multiple- relaxation-time scheme and moment-based boundary conditions to avoid the numer- ical slip error that is associated with standard bounce-back. The model’s accuracy and robustness is demonstrated by an excellent agreement between our results and benchmark data for thermal flows ranging from Ra = 103 to 108. Our thermal model captures analogous flow behavior to that of CO2 through fluid-filled porous media, including the transition from diffusive transport to initiation and development of convective fingering.

روابط وملفات

التعريف والنوع

رقم الوثيقة

0fe479e5-c765-4a71-ba61-7bb6c4b27181

رقم العقد

0

نوع الوسائط

Crawler

نوع المحتوى

الرسائل العلمية

صيغة المصدر

رسائل دكتوراة

نوع الملف

pdf text

أسماء الملفات

1700216_1.pdf

بيانات النشر

ألقاب المؤلفين

[{"name_ar":"Shuyu Sun","title_ar":"اشراف","title_en":"Supervision"},{"name_ar":"ريبيكا ألين","title_ar":"اعداد","title_en":"Preparation"}]

اللغة

English

المصدر والدورية

اسم المصدر

Modeling Diffusion and Buoyancy-Driven Convection with Application to Geological CO₂ Storage

المحتوى والصفحات

عدد الصفحات

0

كلمات الباحثين

buoyancy-driven Convection , effective properties , Finite Difference , geological CO2 storage , Lattice Boltxmann method , Porous media

إشراف وإعداد

الإشراف

Shuyu Sun

الإعداد

ريبيكا ألين

الاقتباسات الببليوغرافية