CHARACTERIZATION, EXPERIMENTAL AND MODELING STUDY OF REACTIVE FLOW IN CARBONATES
TITLE:
CHARACTERIZATION, EXPERIMENTAL AND MODELING STUDY OF REACTIVE FLOW IN CARBONATES
DATE:
Friday, Oct 21th, 2011
TIME:
3:30 PM
LOCATION:
GMCS 214
SPEAKER:
Yelena Sholokhova
Lawrence Livermore National Laboratory (LLNL)
ABSTRACT:
The Weyburn-Midale reservoir is dominated by carbonate mineralogy that will partially dissolve as the acid CO2-rich waters used in the EOR operation react with the formation rock, altering the porosity and permeability. Our experimental and modeling study aims to quantify the relationship between fluid flow, heterogeneity, and reaction rates specific to carbon storage at the Weyburn-Midale field by integrating characterization, solution chemistry, and simulated data. We present the results of core flood experiments that reacted the Midale Marly (M3) dolostone and Vuggy (V6) limestone flow units with brines equilibrated with pCO2 = 0.5 to 3 MPa, and caprock, the Three Fingers evaporite with pCO2 = 3 MPa. In this work, we present a methodology to characterize these carbonate cores that consists of characterization of the submicron-scale heterogeneities using Scanning Electron Microscopy (SEM) and the larger-scale (micron to millimeter) heterogeneities using X-ray computerized microtomography (XCMT).
Our study shows that the degree of void space and mineralogical heterogeneity of carbonate rocks drives the development of the dissolution fronts and the resulting relationships between porosity and permeability. Homogeneous distribution of pore space leads to stable dissolution fronts where the change in porosity leads to small changes in permeability. However, a heterogeneous distribution of pore space leads to unstable dissolution fronts and dramatically increases permeability by several orders of magnitude. Our simulated results suggest that Darcy continuum scale models can adequately model stable reaction fronts for highly porous rocks with a uniform distribution of pore space, as is the case for the Marly cores. However, our ability to model the evolution of unstable reaction fronts that develop in the highly heterogeneous Vuggy limestone is limited by our ability to properly scale this heterogeneity and capture the fast channel (wormhole)–flow phenomena.
HOST:
Dr. Christopher P. Paolini.
DOWNLOAD: