World Applied Sciences Journal 16 (1): 147-155, 2012
ISSN 1818-4952
© IDOSI Publications, 2012
Reserves Reporting and the Market Value of Oil Companies: A Comparative Study
Mohammad Reza Moghaddam
Institute of Energy Economics, Petroleum University of Technology, Tehran, Iran
Abstract: The oil producing country needs a real view of its oil reserves and the forecasts of production, to
cover its annual expenditures. The most influence is on their market value which mostly depends on their
reserves. Oil companies can build better investment portfolios or divest in particular fields. Finally, the investors
and global bankers seek to use better data for comparing investment opportunities and financing projects. The
geologists and petro-physicists experts estimate “oil-in-place” with 10% error in their formulas. Reservoir
engineers use hydrocarbon features to estimate the “reservoir” or “recoverable oil” volumes. These estimates
can be influenced by improper explanation of seismic, inadequate sampling for depth estimates, quality and
recovery factor to create uncertainties. These figures may change the value of resource by inflation, market
prices and financial regimes. The most uncertainties are in exploration stage. The regular and accurate reserves
reporting of the world energy reserves, can guarantee “the supply security”. This paper examines the reports
on reserves and the history of reports and investigates the data on reserves according to Society of Petroleum
Engineers - World Petroleum Council - Geologist American Association of Petroleum (SPE/WPC/GAAP) and
United Nations (UN) standards. At the end, necessary actions taken to improve the estimates of oil reservoirs.
Key words: Reserves reporting Oil in place
JEL: Q41-Q47-D89- Q01
Uncertainty
INTRODUCTION
Oil reserves classification
Oil recovery
classification and improvements on this matter would be
discussed.
Is it possible to look at a stone and guess its history?
Is it just a stone or a remainder of a castle or a huge
temple? Hydrocarbour Reservoir Reporting (HRR) faces
also with such a question. HRR is defined in literature as
"estimating reserves remains as much an art as a
science" [1]. On November 2004, International Energy
Agency (IEA) defined HRR as "efforts have to be made to
improve
the
transparency,
consistency
and
comprehensiveness of data reserves and resources" [2].
The regulations are given by the Energy or Petroleum
Ministries. Less efforts has been carried out till 1984 to
re-estimate the reservoirs of oil-rich countries. The
discrepancies between numbers of reserves estimates
done by different institutions are remarkable. Even a few
countries has established new laws to clarify the
generated data, to avoid any errors and misleading figures
on oil reserves.
However, HRR may mislead the decision makers.
Can HRR influence the market value of oil companies? Is
it reasonable to trust on HRR? Can HRR have any effects
on energy supply? In the first part of present paper, HRR
and the record of reserves is discussed. In the second
part, the estimates, according to SPE/WPC/GAAP and UN
From "Resources" to "Reserves": Geologists, Petrophysicists and Reservoir Engineers estimate the amount
of resource as oil-in-place (OIP) or original-oil-in-place
(OOIP) with (+/- 10%) error for each parameter. Sometimes
OIP or OOIP varies about two times more than the
estimated value. In these calculations reservoir area and
vertical thickness or depth estimates total volume of the
reservoir. The reservoir porosity, saturation (oil or gas
versus water), fluid properties and permeability are used
to estimate recovery rate (average of 35% for oil 80-85%
for gas) and profitability (depends on technology and
price of oil) [3, 4].
From "Certainty" to "Uncertainty": the Difference
Between Risk and Uncertainty: In a very simple way
"risk" is defined as chance that project will produce
"revenues". Before drilling, resources might not be there
or discovered resources may not be developed; because
of technological or economic reasons. "Uncertainty"
means range of possible outcomes (volume/value), if
project goes ahead [5]. For volumes, there are some
parameters which face risky fields such as:
Corresponding Author: Mohammad Reza Moghaddam, Scholar and Vice Minister of Petroleum Ministry of Iran in Research
and Technology, Tehran, Iran.
147
World Appl. Sci. J., 16 (1): 147-155, 2012
Seismic … ray path geometries, navigation,
interpretation.
Depth conversion … inadequate sampling.
Reservoir continuity … sedimentological structure.
Reservoir quality … petrophysical interpretation,
inadequate sampling.
Fluid properties … inadequate sampling.
Recovery factor… inadequate sampling.
For value, there are parameters such as:
Future costs, influenced by inflation and escalation.
Future prices influenced by market.
Fiscal regime influenced by adjustments.
Fig. 1: Reservoir estimation during time [6]
Figure 1 shows the tracking volumetric uncertainty
from exploration (uncertainty) and appraisal stage to
develop production and field abandonment stage duration
time.
The highest range of uncertainty exists at exploration
level. After exploration, there is remarkable difference
between high and low estimates for recovery factor. At
development and production stage, uncertainty is low
which lasts to abandonment time. Figure 2 depicts the
world production of oil pyramid for average production
(b/d) of field throughout the world. About 20 percent of
fields (14 fields) produced 1 million barrels of oil per day
and 12 fields about 6 percent. More than 400 fields
produced about 53 percent of oil [7, 8].
An extensive studies showed that from 600
sedimentary basins (onshore and shallow water) two
fields in Middle-east produce more than 50 billion bbl and
37700 fields produce less than 25 million bbl of oil [8, 10].
About 95 percent of fields consist more than 100 million
bbl and 60-70 percent consist more than 500 million bbl of
reserves. Tables 1 and 2 show the year and initial reserves
of giant oil fields [7].
Fig. 2: World Oil Production Pyramid [9]
Table 1: The Giant Oil Fields [7]
Initial /today
Oil field (Country)
Year of
reserves
discovery
(Billion bbl)
Ghawar (Saudi Arabia)
1948
70-115
Production %
50-60
Burgan (Kuwait)
1938
49/72
70
Bolivar Coastal (Venezuela)
1917
15/32
40
Safaniya (Saudi Arabia)
1951
19/30
200 >
Rumaila (Iraq)
1953
20
-
Ahwaz (Iran)
1958
17.5
-
Kirkuk (Iraq)
1927
16
-
Table 2: The Giant Gas Fields [7]
Reserves Reporting: for What and How World Reserves
Are Categorized: The necessity for report world's energy
reserves as precise as possible, specially oil, can be
discussed from different aspects. Producing country
needs a realistic view of the entire petroleum resource
base. Worldwide view needs a certain energy supply. Oil
company wants a better management of upstream
business or "Portfolio Management": Farm in / out. The
"value of company" depends on reserves that are
strongly correlated to future income from production and
thereby to the value of the future cash flow. "Operation"
needs accurate data to do better cost-control, finding,
development costs and reserve replacement ratio.
Gas field (Country)
Initial /today reserves (Trillion Cubic meters)
North Field (Qatar)
8.0
Urengoi (Russia)
6.6
Yamburg (Russia)
4.6
Bovanenkov (Russia)
4.4
South Pars (Iran)
2.8
Groningen (Netherlands)
2.3
"Investors (shareholders) and lenders (banks)" do
financial management to compare investment
opportunities and "Project Financing". International
organizations such as OPEC, IEA and WPC follow
agreements [11]. The professional national and
148
World Appl. Sci. J., 16 (1): 147-155, 2012
Governemental
Level
International
Organization
Professional
Organization
Oil Company
Laws & Regulations
Agreements
Definitions
Stanadard
Recommendations
Internal
Processes
Ministry
of
Energy
Exchange
USGS
EIA
NPD
DTI
SEC
ASC
LSE
AMF
Stock
WPC
IEA
OPEC
International
National
SPE
AAPG
SPEE
API
CIM
Fig. 3: Main players in world oil industry [15]
Resources
Reservoir Identified
Speculative Yet to find
Proved Reserves P or P90
Unproved reserves
Developed
Undeveloped
Probable 2P
or P50
Possible 3P
or P10
Fig. 4: Categories of reserves SPE/WPC [14]
international organizations such as API, CIM and SPE,
SPEE and AAPG recommend standards and definitions
[12-14]. The oil companies do internal process such as
exploration, extraction and refining (Figure 3).
The main players in world oil industry are:
governments, international organizations, professional
and oil companies. At the governmental level, laws and
regulations are established. Ministry of Energy and
agencies such as USGS and EIA in USA, NPD in Norway
and DTI in UK and Stock Exchange or Accounting
Authorities such as SEC (USA), ASC and OSC (Canada),
LSE (UK) and AMF (Fr) play critical roles at this level
[3, 4].
Reserves/resources history starts at FSU system in
1940s. On 1965, SPE (Society of Petroleum Engineers)
defines "proved reserves". On 1987, SPE defines
"probable and possible reserves" On 1997, SPE and WPC
(World Petroleum Congress) present their reserves
definitions. On 2000, SPE/WPC/AAPG (American
Association of Petroleum Geologists) defines new
definitions and classification system and finally United
Nations Framework Classification (UNFC) is presented on
2004 [2, 13, 15, 16].
Categories of Reserves Based on SPE/WPC: These two
companies defined and categorized oil resources on 1997
(Figure 4). According to this figure, "identified
reservoirs" are divided at "proved (probable more than
90%) and unproved (probable less than 50 and 10%"
reserves. Among these, the proved reserves are divided
at "developed" and "undeveloped" reservoirs. Figure 4
shows this classification.
If deterministic methods are used, the term
"reasonable certainty" is intended to express a high
degree of confidence that the quantities will be
recovered (as best estimate). If probabilistic methods
are used, there should be at least a 90% probability
that the quantities actually recovered will equal or
exceed the estimate. Table 3 and Figure 5 show the
classification.
149
World Appl. Sci. J., 16 (1): 147-155, 2012
Categories of Reserves Based on SPE/WPC/AAPG:
These three organizations classified reserves based on
Table 4. Resources are not categorized as reserves today
but perhaps for tomorrow. They divided into contingent
and prospective resources. "Contingent" means
quantities of petroleum which are estimated, on a given
date, to be potentially recoverable from known
accumulations but which are not currently considered to
be commercially recoverable. "Prospective" means
quantities of petroleum which are estimated, on a given
date, to be potentially recoverable from undiscovered
accumulations. Tables 4 and 5 show the categories of
reserves based on deterministic and probabilistic
methods.
Fig. 5: Categories of reserves based on probabilistic
method, SPE [15]
Table 3: Categories of reserves SPE/WPC [14]
(Reasonable certainty)
Deterministic (proved reserves)
(more likely than not)
(probable reserves)
(less likely than probable)
(possible reserves)
At least 90% probability (P90)
Probabilistic 1P: proved
At least 50% probability (P50)
2P: proved + probable
At least 10% probability (P10)
3P: 2P+ possible
Categories
of
Reserves
Based
on UN
Classification: The UN categorizes resources into
"renewable" and "non-renewable". This classification
is consistent
with
SPE/WPC/AAPG definition.
Table 4: SPE/WPC/AAPG Resource Classification System [14]
Range of Uncertainty
-------------------------------------------------------------------------------------Discovered Commercial
Production
Project status
Reserves
On Production
1P
Discovered Sub Commercial
Undiscovered
3P
Under Development
Best estimate
High estimate
Development pending
Contingent Resources
Low estimate
Lower Risk
2P
Planned for Development
Unrecoverable
Development not viable
Prospective Resources
Prospect
Low estimate
Best estimate
High estimate
Unrecoverable
Project Maturity
Higher Risk
Lead
Play
Table 5: Norwegian Classification: NPD/FUN adaptation of SPE classification [15]
SPE/WPC/AAPG
NPD/FUN
---------------------------------------------------------------------------------------------------------
---------------------------------------------
Resource class
Project Status Category: 10 different
Sold and Delivered petroleum
0
Sold and Delivered petroleum
Dominant costs
Reserves
1
In production
Planning and Depreciation
Undiscovered petroleum
2A/F
Approved development plan
Development
initially in place
3A/F
Decided for development
Planning and Engineering
4A/F
In Planning
Planning and Engineering
5A/F
Unclarified
Research, development
6
Not very likely
Relinquishment cost
7A/F
Not evaluated
Exploration
8
Prospect
Exploration
9
Lead
Exploration
Total petroleum initially in place
Commercial
Sub-commercial Contingent resources
and exploration
Unrecoverable
Undiscovered petroleum
Prospective resources
initially in place
Unrecoverable
NPD: Norway Petroleum Directorate
FUN: Forum for European Uncertainty Evaluation
150
World Appl. Sci. J., 16 (1): 147-155, 2012
Reservoir Identified
Proved Reserves
Proved Developed
Reserves
Unproved Reserves
Proved Undeveloped
Reserves
Fig. 6: The SEC Definition for reserves [17]
Additional oil and gas expected to be obtained
through fluid injection or other improved recovery
techniques should be included as proved developed
reserves only after testing by a pilot project or after
the operation of an installed program has confirmed
that increased recovery will be achieved.
The United Nations Framework Classification (UNFC) for
Energy (non renewable) and mineral resources is a
universally applicable scheme for classifying/evaluating
energy and mineral reserves. The classification which is
harmonized with the SPE/WPC/AAPG petroleum resource
classification was developed by an intergovernmental
group of experts [14].
Remaining resources are categorized using 3 essential
criteria (Table 7):
Proved Undeveloped: expected to be recovered from
new wells on undrilled acreage, or from existing wells for
which a relatively major expenditure is required:
Economic and commercial viability (E): Economic axis
with 3 levels E1, E2, E3 (current or future costs, prices
and taxes).
Field project status and feasibility (F): Feasibility axis
with 3 levels F1, F2, F3 (technology and
environmental constraints).
Geological knowledge (G): Geological axis with 4
levels G1, G2, G3, G4 (petroleum initially in place
estimates and reservoir characteristics).
Reserves on undrilled acreage should be limited to
immediate adjoining productive units (one offset)
that are reasonably certain of production when
drilled.
Proved reserves for other undrilled unit scan be
claimed only if it can be demonstrated with certainty
that there is continuity of production from the
existing productive formation.
For example, E1, F1, G1 = Proven reserves. All fields
with E1 and F1 are classified as reserves. Contingent
reserves = no E1 or no F1 since they cannot be developed
without a significant rise in crude price or new
technology.
Table 6 shows the main differences between SPE and
SEC Definitions.
Reserves Revisions: For majors, integrated, independent
oil and gas companies need SEC requirements and there
is no requirement for an external reserves audit. The
companies book and publish the proven only except in
the UK, Australia and Canada: some companies published
proven and probable, UK (LSE) and proved or proved and
probable. Definition of reserves given by Statement of
recommended practice (SORP) is "no difference between
SORP and SEC".
Canada has introduced new disclosure rules under
National Instrument NI-501 and published the Canadian
Oil and Gas Evaluation (COGE) Handbook about: Proven
and probable with probabilities (no deterministic), Proved
(> P90) and Future Net Revenues (FNT) and Proved and
Probable (> P50) [18].
Categories of Reserves Based on UN Classification: The
SEC definition for reserves is shown in Figure 6.
The "Proved developed" is expected to be recovered:
Through existing wells with existing equipment and
operating methods (existing wells subjected to a
conclusive production test: a fluid test is not a
conclusive production test) only from tested wells,
but after lobbying from the industry, cheaper data
sources are allowed in the GoM, but not overseas:
log, core, seismic.
151
World Appl. Sci. J., 16 (1): 147-155, 2012
Table 6: Comparison between definitions of two organizations
SEC
SPE / WPC
Securities reporting
General application
Reasonable certainty to be recoverable
Reasonable certainty to be commercially recoverable
Qualitative description of certainty-proved
Probability associated with estimates
Not addressed
Proved, Proved + Probable
Pricing
Prices and costs as of date of estimate
Existing economic conditions
Development and production status categories
Developed Undeveloped
Developed Undeveloped
Intended purpose
Developed producing
Developed non-producing
Undeveloped
Table 7: Reserves Revisions [20]
Year
Venezuela
Kuwait
Iraq
Iran
Dubai
Abu Dhabi
1980
17.9
Saudi Arabia
163.4
65.4
31.0
58.0
1.4
28.0
1981
18.0
165.0
65.9
30.0
57.5
1.4
29.0
1982
20.3
165.0
64.5
30.0
57.0
1.4
30.6
1983
21.5
162.4
64.2
41.0
55.3
1.4
30.5
1984
24.9
166.0
63.9
43.0
51.0
1.4
30.4
1985
25.9
169.0
90.0
45.0
48.5
1.4
30.5
1986
25.6
168.8
92.0
44.0
47.9
1.4
30.0
1987
25.0
166.6
92.0
47.0
48.8
1.4
31.0
1988
56.3
167.0
92.0
100.0
92.9
4.0
92.2
1989
58.1
170.0
92.0
100.0
92.9
4.0
92.2
1990
59.1
257.5
92.0
100.0
92.9
4.0
92.2
1991
59.1
257.5
94.0
100.0
92.9
4.0
92.2
1992
62.7
257.5
94.0
100.0
92.9
4.0
92.2
1993
63.3
257.5
94.0
100.0
92.9
4.0
92.2
1994
64.5
257.5
94.0
100.0
89.3
4.3
92.2
1995
64.9
257.5
94.0
100.0
88.2
4.3
92.2
1996
64.9
257.5
94.0
112.5
93.0
4.0
92.2
1997
71.1
261.0
94.0
112.5
93.0
4.0
92.2
1998
72.6
261.0
94.0
112.5
89.7
4.0
92.2
1999
72.6
261.0
94.0
112.5
89.7
4.0
92.2
2000
76.9
261.0
94.0
112.5
89.7
4.0
92.2
2001
77.7
260.0
94.0
112.5
89.7
4.0
92.2
2002
77.7
260.0
94.0
112.5
89.7
4.0
92.2
2003
77.7
260.0
94.0
112.5
89.7
4.0
92.2
2004
77.7
260.0
94.0
112.5
89.7
4.0
92.2
2005
77.7
260.0
94.0
112.5
89.7
4.0
92.2
2006
77.7
260.0
94.0
112.5
89.7
4.0
92.2
2007
77.7
260.0
94.0
112.5
89.7
4.0
92.2
Tables 7 and 8 show the revisions of reserves for
OPEC members. According to these tables, till 1984 there
were no serious attempts to reevaluate the reserves of oil
rich countries. Since 1985 Kuwait began re-estimating of
its crude oil reserves seriously. The UAE, Iran, Venezuela
and Iraq stated new numbers for their reserves. Saudi
Arabia had changes in 1990 [19]. Table 10 shows reserves
revisions for regional groups. The revisions are
remarkable for Middle East, USA and Africa, but less
changes are seen for Canada and Asia Pacific.
Table 8: Reserves Revisions (million bbl) [8]
Country/region
2002
2003
Middle east
685.0
685.0
USA
22.0
22.4
Canada
149.0
180.0
The rest America
122.0
111.2
Africa
77.0
77.4
West Europe
17.1
18.1
Asia Pacific
Total
152
43.8
38.7
1031.5
1212.8
World Appl. Sci. J., 16 (1): 147-155, 2012
Table 9: Discrepancies between numbers of Reserves Revisions (million bbl) [2]
Country
Resources to be discovered (Billion bbl)
Proven reserves (Billion bbl)
Proven reserves (Billion bbl)
Saudi Arabia
136
259
262
Russia
116
49
49
49
51
131
113
113
Iran
67
90
90
90
UAE
10
98
98
59
Iraq
Kuweit
Proven reserves (Billion bbl)
259
4
97
97
55
USA
83
22
30
32
Venezuela
30
24
78
78
Libya
9
30
30
25
China
17
24
24
25
Mexico
23
27
27
22
Nigeria
43
24
24
20
Kazakhstan
25
5
8
20
Norway
23
9
9
16
Algeria
10
9
9
15
930
946
831
1032
1050
Total
640
Total worldwide
Table 10:
Discrepancies between numbers of Reserves Revisions (million
bbl) [2]
Country
OPEC
IEA
Saudi Arabia
263
263
World Oil
259
O& GJ
259
Iran
133
131
105
126
Iraq
115
115
115
115
UAE
98
98
66
98
Kuwait
99
97
97
97
Venezuela
77
78
52
78
Russia
69
69
65
60
Libya
39
36
31
36
Nigeria
35
34
33
25
USA
23
31
23
23
Fig. 7: Ultimate Oil Resources [1]
Tables 9 and 10 show discrepancies between
numbers of reserves revisions revised by international
institutions. The OPEC and BP stated more data.
Preventive Activities on Oil Reserves Revisions: There
are new regulations to prevent from incorrect and
misleading estimates. Sarbanes- Oxley Act was signed by
President Bush in 2002 [21], which applies to all
companies that publicly issue securities listed on an US
stock exchange or quoted on NASDAQ. In section
302/906: Management (CEO) has to certify corporate
responsibility, or in section 404, management should
assess effectiveness of a company's internal control over
all financing reporting. Annual report has to contain an
"internal control report". External audit attests and reports
on assessment made by the company's management.
Reserves are not audited but can be certified.
Fig. 8: Pessimistic Hubbert Curve: decline from the midpoint
Figure 7 shows ultimate Oil Resources. New
discoveries don’t compensate consumption during 1999
-2003. New discoveries are smaller and will be more
expensive to produce. The largest potential of large new
discoveries is located in areas that are still partly closed
to private investment.
153
World Appl. Sci. J., 16 (1): 147-155, 2012
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Fig. 9: Pessimistic Discoveries of giant oil fields since
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5.
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8.
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11.
The first reservoir reporting system was
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security. Also a good estimate can influence the market
value of oil companies.
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