Simulating the Cranfield geological carbon sequestration project with high-resolution static models and an accurate equation of state

Abstract

A field-scale carbon dioxide (CO2) injection pilot project was conducted as part of the Southeast Regional Sequestration Partnership (SECARB) at Cranfield, Mississippi. We present higher-order finite element simulations of the compositional two-phase CO2-brine flow and transport during the experiment. High-resolution static models of the formation geology in the Detailed Area Study (DAS) located below the oilwater contact (brine saturated) are used to capture the impact of connected flow paths on breakthrough times in two observation wells. Phase behavior is described by the cubic-plus-association (CPA) equation of state, which takes into account the polar nature of water molecules. Parameter studies are performed to investigate the importance of Fickian diffusion, permeability heterogeneity, relative permeabilities, and capillarity. Simulation results for the pressure response in the injection well and the CO2 breakthrough times at the observation wells show good agreement with the field data. For the high injection rates and short duration of the experiment, diffusion is relatively unimportant (high Péclet numbers), while relative permeabilities have a profound impact on the pressure response. High-permeability pathways, created by fluvial deposits, strongly affect the CO2-transport and highlight the importance of properly characterizing the formation heterogeneity in future carbon sequestration projects.

Numerical Modeling of Methane Leakage from a Faulty Natural Gas Well into Fractured Tight Formations

“…The hydraulic properties are inspired by the Cranfield large volume CO 2 injection pilot project (Hosseini et al 2013;Soltanian et al 2016), but scaled to the same domain dimensions and dip as in the previous example. Fluvial channels introduced marked heterogeneity in many aquifers and can create preferred flow pathways.…”

Transport of perfluorocarbon tracers in the Cranfield Geological Carbon Sequestration Project

“…We simulate the transport of brine‐CO 2 and tracers using EOS‐based phase stability and phase split algorithms developed in prior work . The governing equations for species transport in the two‐phase brine‐CO 2 and tracers system are found in section 3 of Soltanian et al …”

“…The CO 2 was injected through an injection well, F1, and was monitored by two observation wells F2 and F3 (see Fig. 2 in Soltanian et al …”

“…Carbon Capture and Storage (CCS) is a promising technology to mitigate increasing atmospheric carbon dioxide (CO 2 ) concentrations . Identifying and quantifying the processes that affect CO 2 transport in the subsurface are essential to predict CO 2 residence times and to estimate the storage capacity of a reservoir.…”

“…Earlier studies had mostly relied on upscaled petrophysical properties (e.g., permeability and porosity) and relatively coarse grids, and were conducted using, e.g., CMG, IPARS, iTOUGH2, TOUGH2/EOS7C, STOMP‐CO2e, TOUGH2‐MP/ECO2N, VESA, and MoReS . In Soltanian et al ., we also performed extensive parameter studies to investigate the relative importance of capillarity, Fickian diffusion, relative permeability, and sedimentary architecture (e.g., fluvial channel) effects and found that flow was highly advection dominated. We use those initial models for CO 2 ‐brine flow as a baseline for the tracer simulations in this work, i.e., the transport of SF 6 and a suite of four different PFTs that were co‐injected with CO 2 including PMCP, PMCH, PTCH, and PECH/PDCH (collectively referred to as PDCH).…”