Phase III - Department of Mines and Petroleum

ecosystems. The GJV Ecological Monitoring Plan’s activities and methods should be incorporated into
monitoring activities for the CO 2 disposal project. As a minimum, it is strongly recommended that an
assessment of the possible impacts and recovery rates from CO 2 exposure for key receptors be undertaken
in future technical work.
The overall Monitoring and Surveillance Plan as proposed by the GJV is generally very thorough with clear
well-defined objectives. Time-lapse seismic is identified as the key monitoring tool and hence it is strongly
recommended that the results from the seismic pilot test (including their integration into the 3D baseline
survey planning process) are reviewed as part of any Phase IV due diligence. We further recommend that
overall spatial repeatability should be tested by an early repeat 3D survey (~2 years after start of injection).
For the proposed soil gas survey, the GJV should carefully assess the required density of sampling points,
with additional sites around wells, and potentially incorporating long term flux and concentration data. It is
expected that results from the soil gas pilot study and plans for the baseline soil gas monitoring survey will
be reviewed as part of any Phase IV due diligence.
Since observation wells could provide the most valuable data points with respect to plume migration
verification, it will be important to confirm the saturation measurements obtained from well logging
programs. It is recommended that the GJV review their decision to not acquire fluid samples during
saturation logging in observation wells. It is considered important that the GJV continues to review
advances in technology on the most appropriate tool to measure changes in reservoir saturation and we
strongly recommend that the GJV update current log modelling activities in support of the decision on
which logging technology is to be used for saturation measurements. Signposts should be refined to reflect
the importance of injection well pressure measurements, the process by which pressure data are used to
constrain simulation models should be clarified, and the workflow for calibration (and up-scaling) of
saturation logging results for simulation modelling should be described. Even though the preliminary
locations of the observation wells have been chosen, it is recommended that provision be included for
changes to locations of the observation wells and timing of monitor surveys as new information becomes
available on the rate and direction of the migrating plume.
The Due Diligence Team believes that these recommendations can be accommodated in the GJV Phase IV
technical work programme.
xxxix