12 February 2013
Surprise Update
Central Petroleum Ltd (ASX:CTP, ‘the Company’) advises it has completed a
substantial program of technical analysis following the Surprise discovery, and has
investigated the surrounding structures and adjacent formations.
The result of the work has indicated that there are multiple zones within Surprise that
have high-reward potential and warrant enhanced exploration efforts. This information
has had a positive impact on our views of the timing and costs of bringing Surprise into
The program included extended production testing, 3-D seismic-based interpretation,
reservoir modelling and pressure transient analysis. We anticipate being in a position to
announce the Surprise volumes and reserves this quarter.
Regional Geology
The Company believes that the Horn Valley Siltstone (HVS), located stratigraphically
below the Surprise reservoir and extending for thousands of square kilometres, is the
regional oil source for the known oil discoveries in the North-Western Amadeus Basin.
The 3-D seismic indicates that the HVS thickens coming off the Surprise structure. Our
interpretation is that basinal areas straddling the Surprise structure may be rich, highly
prospective areas for a HVS shale oil/gas play.
The Company has resolved to allocate more resources to defining this potentially large
unconventional oil/gas play over time (see Figure 1 - “Surprise Discovery Area
Schematic” attachment).
Interpretation of the Surprise structure
Transient pressure analysis would indicate that the lowest known oil at Surprise is now
believed to be deeper than originally estimated as illustrated in the attached Figure 2 -
“Depth Structure Map - Stairway reservoir”.
The oil column is considered to be thicker than previously thought, and this has
improved the estimated development timeframe and economics of the proposed
There may be a structural and/or stratigraphic component to the trap along the ridge to
the east of the structure, where the Stairway reservoir is seismically interpreted to
pinch out into salt. The expanded oil column allows for another well location on the east
side of the fault. Further analysis is underway to determine what additional work is
required to confirm this proposition. Such work may be carried out after Surprise
comes into production.
Other hydrocarbon targets
The company believes there may be reason to not only test the HVS but also the lower
formations draped over salt when the Surprise development commences, as indicated
in the third attachment Figure 3 - “Depth Structure Map – near top salt”.
As a result of the program, the Company believes Surprise is an exciting, continuously
evolving exploration area, with the potential size of the reward more than justifying
continued and enhanced exploration efforts.
Of particular interest in further exploration are:
(i) the ridge structure extending east form the Surprise-1 well;
(ii) the possibility of deeper targets draped over, or trapped against, the
underlying salt seen on the 3-D seismic; and
(iii) the HVS shale oil/gas play which sits below the Stairway reservoir (in which
Surprise was discovered).
Media contact
Martin Debelle at Citadel
+61 2 9290 3033 and mobile +61 (0) 409 911 189
General Disclaimer and explanation of terms:
This document may contain forward-looking statements. Forward looking statements are only
predictions and are subject to risks, uncertainties and assumptions which are outside the control of
Central. These risks, uncertainties and assumptions include (but are not limited to) commodity prices,
currency fluctuations, economic and financial market conditions in various countries and regions,
environmental risks and legislative, fiscal or regulatory developments, political risks, project delay or
advancement, approvals and cost estimates. Actual values, results or events may be materially different
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place reliance on forward looking statements. Any forward looking statement in this document is valid
only at the date of issue of this document. Subject to any continuing obligations under applicable law
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circumstances change or that unexpected occurrences happen to affect such a statement. Sentences and
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