Determination of Diffusion Profiles in Altered Wellbore Cement Using X-ray Computed Tomography Methods
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
The development of accurate, predictive models for use in determining wellbore integrity requires detailed information about the chemical and mechanical changes occurring in hardened Portland cements. X-ray computed tomography (XRCT) provides a method that can nondestructively probe these changes in three dimensions. Here, we describe a method for extracting subvoxel mineralogical and chemical information from synchrotron XRCT images by combining advanced image segmentation with geochemical models of cement alteration. The method relies on determining “effective linear activity coefficients” (ELAC) for the white light source to generate calibration curves that relate the image grayscales to material composition. The resulting data set supports the modeling of cement alteration by CO2-rich brine with discrete increases in calcium concentration at reaction boundaries. The results of these XRCT analyses can be used to further improve coupled geochemical and mechanical models of cement alteration in the wellbore environment.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC52-07NA27344
- OSTI ID:
- 1136144
- Journal Information:
- Environmental Science and Technology, Vol. 48, Issue 12; ISSN 0013-936X
- Publisher:
- American Chemical Society (ACS)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effective Permeability Change in Wellbore Cement with Carbon Dioxide Reaction
Geochemical and Geomechanical Effects on Wellbore Cement Fractures