Annual Report 2004 25
PROVEN PLUS PROBABLE RESERVES (SANTOS SHARE) BY ACTIVITY
Sales gas Crude oil Condensate LPG Total
(incl. ethane) mmbbl mmbbl 000 mmboe
PJ tonnes
Reserves year end 2003 2,670 102 48 3,605 636 
Production -190 -10 -3 -159 -47
Additions 157 1 0 24 29 
Acquisitions/Divestments 110 2 1 98 22 
Revisions 126 -21 3 -45 3 
Estimated reserves year end 2004 2,873 74 49 3,523 643 
PROVEN PLUS PROBABLE RESERVES (SANTOS SHARE) YEAR END 2004 BY AREA 
(mmboe)
Area Sales gas Crude oil Condensate LPG Total
(incl. ethane) mmbbl mmbbl 000 mmboe
PJ tonnes
Cooper Basin 1,051 24 15 1,842 233 
Onshore Northern Territory 147 1 1 0 27 
Offshore Northern Territory 310 1 27 1,507 92 
Eastern Queensland 256 0 0 22 45 
Southern Australia 271 0 2 152 50 
Carnarvon Australia 555 43 3 0 141 
PNG0 1 0 0 1 
Indonesia 243 4 0 0 46 
USA 40 0 1 0 8 
Total 2,873 74 49 3,523 643 
RESERVES (SANTOS SHARE) 
(mmboe)
Year end Production Revisions Additions Acq/Divest Year end
2003 2004
Proven (1P) 338 -47 26 19 12 348 
Proven plus Probable (2P) 636 -47 3 29 22 643 
Contingent Resources (Best Estimate) 1,450 - -4 -13 10 1,443*
* Contingent resources excludes any contribution from Jeruk which was still under evaluation at year end.
DEFINING RESERVES
Santos has in place an evaluation
and reporting process that is in
line with international industry
practice and is in general
conformity with reserves
definitions and resource
classification systems published by
the Society of Petroleum Engineers
(SPE), World Petroleum Congress
(WPC) and the American
Association of Petroleum
Geologists (AAPG). The definitions
used are consistent with the
requirements of the Australian
Stock Exchange Ltd (ASX).
Reserves are defined as those
quantities of petroleum which are
anticipated to be commercially
recovered from known
accumulations from a given date
forward. Santos reports reserves
net of the gas required for
processing and transportation to
the customer. Reserves reported are
based on, and accurately reflect,
information compiled by full-time
employees of the Company who
have the requisite qualifications
and experience prescribed by the
ASX Listing Rules.
EXTERNALLY REVIEWED 
BOOKING PROCESS
Santos’ reserves processes and
procedures were reviewed by
independent expert, Gaffney, Cline
& Associates, and found to be
‘appropriate to providing robust
estimates of Santos’ reserve
position in accordance with
international industry practice’ .
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