Extracted from the Horizon oil quarterly.During the quarter...

Extracted from the Horizon oil quarterly.

During the quarter Horizon Oil’s working interest share of production from Maari and Manaia fields
was 91,367 barrels of oil. Crude oil sales were 73,289 barrels at an average realized price of
US$120.25 per barrel. Cumulative oil production from the fields through 29 April 2012 was 18.1
million barrels.
Production was below forecast due to outages on the MR1, MR3 and MR4 wells and waterflood under
performance. Also a complete production shutdown occurred for a week in early March due to card
failures within the Honeywell distributed control system.
Repairs to the control system were successfully completed and production recommenced. The
Schlumberger electrical submersible pumps in the MR1, MR3 and MR4 wells have been replaced and
MR3 and MR4 are back on production. Planning of further remediation of MR1 is underway to
achieve a reasonable rate of production from the well.
Horizon Oil has carried out its own detailed study of the main Moki reservoir in Maari field, which
was recently audited by the technical experts appointed by the banks participating in the reserves
based lending facility. The study results indicate that improved production can be obtained from the
upper cycle of the Moki by recompleting the existing MR7 and MR8 water injection wells in that zone
and the field operator, OMV, is currently implementing this work. Horizon Oil also believes that
significant additional oil can be recovered from the lower cycle of the Moki with an additional
production well in that zone.
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Plans for additional development of the Maari and Manaia fields are in progress. A new 3D seismic
survey commenced on 23 March 2012 using the vessel MV Polarcus Alima. The survey was
completed on 17 April 2012, having acquired 288 sq km of 3D coverage. The survey experienced
some weather downtime but was completed in good time with good quality data and within budget.
The survey will provide a basis for selecting locations for vertical Manaia Deep and Maari South
appraisal wells and a third possible deep appraisal well on the Maari structure itself. With reference to
the schematic cross-section below, the first of these will target the discovered but unappraised and
undeveloped accumulation in the Manaia Moki sands. The well will also allow assessment of how the
current production well is draining the Mangahewa accumulation and confirm whether there is
commercial oil recoverable from the deeper F sand equivalent, in which oil shows were encountered in
the Maui-4 well and which is a proven oil producer elsewhere in the Taranaki Basin. The second
appraisal well will be drilled to confirm the reservoir quality and size of the Maari South structure
which can potentially be developed by extended reach drilling from the Maari platform. It is expected
that the appraisal wells will be drilled in the 2012/13 summer drilling season.

PEP 51313, Offshore Taranaki Basin, (Horizon Oil interest: 30%)
Approximately 30% of the recently acquired 3D seismic survey is within PEP 51313 and is designed
to merge with the Matariki 3D seismic survey acquired in 2010 (see map above). This will provide
definition over the leads and prospects to the south of Maari and Manaia, in particular Pike prospect.
It is likely that Pike will be drilled using the rig to be mobilised for drilling of two appraisal wells in
PMP 38160 in 2012/2013. This is seen as a progressive, risk-reducing approach to evaluating the
prospectivity of the Tasman ridge to the south, including Matariki prospect.

Cheers,
Kimbo