Main Maracaibo Basin, Assessment Unit 60990101 0 50 100 150 200 250 300 350 400 450 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 DRILLING-COMPLETION YEAR CUM. NEW-FIELD WILDCAT WELLS (No.)
Main Maracaibo Basin, Assessment Unit 60990101
0
50
100
150
200
250
300
350
400
450
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
DRILLING-COMPLETION YEAR
CU
M. N
EW
-FIE
LD
WIL
DC
AT
WE
LL
S (
No
.)
Main Maracaibo Basin, Assessment Unit 60990101
0
5
10
15
20
25
30
35
1914
1917
1920
1923
1926
1929
1932
1935
1938
1941
1944
1947
1950
1953
1956
1959
1962
1965
1968
1971
1974
1977
1980
1983
1986
1989
1992
1995
DRILLING-COMPLETION YEAR
NE
W-F
IEL
D W
ILD
CA
T W
EL
LS
(N
o.)
Main Maracaibo Basin, Assessment Unit 60990101
1
10
100
1,000
10,000
100,000
0 2 4 6 8 10 12 14 16
OIL-FIELD RANK BY SIZE
KN
OW
N O
IL-F
IEL
D S
IZE
(M
MB
O)
First third of fields discovered
Second third of fields discovered
Third third of fields discovered
Main Maracaibo Basin, Assessment Unit 60990101
0
1
2
3
4
5
6
7
8
1 to
<2
2 to
<4
4 to
<8
8 to
<16
16 to
<32
32 to
<64
64 to
<12
8
128
to <
256
256
to <
512
512
to <
1,02
4
1,02
4 to
<2,
048
2,04
8 to
<4,
096
4,09
6 to
<8,
192
8,19
2 to
<16
,384
16,3
84 to
<32
,768
32,7
68 to
<65
,536
65,5
36 to
<13
1,07
2
131,
072
to <
262,
144
>=26
2,14
4
KNOWN OIL-FIELD SIZE (MMBO)
OIL
FIE
LD
S (
No
.)
Third third offieldsdiscovered
Second thirdof fieldsdiscovered
First third offieldsdiscovered
Main Maracaibo Basin, Assessment Unit 60990101
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
1 to
<2
2 to
<4
4 to
<8
8 to
<16
16 to
<32
32 to
<64
64 to
<12
8
128
to <
256
256
to <
512
512
to <
1,02
4
1,02
4 to
<2,
048
2,04
8 to
<4,
096
4,09
6 to
<8,
192
8,19
2 to
<16
,384
16,3
84 to
<32
,768
32,7
68 to
<65
,536
65,5
36 to
<13
1,07
2
131,
072
to <
262,
144
>=26
2,14
4
KNOWN OIL-FIELD SIZE (MMBO)
VO
LU
ME
OF
OIL
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
1
10
100
1,000
10,000
100,000
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
FIELD-DISCOVERY YEAR
KN
OW
N O
IL-F
IEL
D S
IZE
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
1
10
100
1,000
10,000
100,000
0 50 100 150 200 250 300 350 400 450
CUM. NEW-FIELD WILDCAT WELLS (No.)
KN
OW
N O
IL-F
IEL
D S
IZE
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
0
10,000
20,000
30,000
40,000
50,000
60,000
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
FIELD-DISCOVERY YEAR
CU
M. K
NO
WN
OIL
VO
LU
ME
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
0
10,000
20,000
30,000
40,000
50,000
60,000
0 50 100 150 200 250 300 350 400 450
CUM. NEW-FIELD WILDCAT WELLS (No.)
CU
M. K
NO
WN
OIL
VO
LU
ME
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
0
5
10
15
20
25
30
35
40
45
50
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
FIELD-DISCOVERY YEAR
CU
M. O
IL F
IEL
DS
(N
o.)
Main Maracaibo Basin, Assessment Unit 60990101
0
5
10
15
20
25
30
35
40
45
50
0 50 100 150 200 250 300 350 400 450
CUM. NEW-FIELD WILDCAT WELLS (No.)
CU
M. O
IL F
IEL
DS
(N
o.)
Main Maracaibo Basin, Assessment Unit 60990101
0
1,000
2,000
3,000
4,000
5,000
6,000
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
FIELD-DISCOVERY YEAR
RE
SE
RV
OIR
DE
PT
H, O
IL F
IEL
DS
(m
)
Main Maracaibo Basin, Assessment Unit 60990101
0
1,000
2,000
3,000
4,000
5,000
6,000
0 50 100 150 200 250 300 350 400 450
CUM. NEW-FIELD WILDCAT WELLS (No.)
RE
SE
RV
OIR
DE
PT
H, O
IL F
IEL
DS
(m
)
Main Maracaibo Basin, Assessment Unit 60990101
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
0 1,000 2,000 3,000 4,000 5,000 6,000
MEAN RESERVOIR DEPTH (m)
GA
S/O
IL, O
IL F
IEL
DS
(C
FG
/BO
)
Main Maracaibo Basin, Assessment Unit 60990101
0
20
40
60
80
100
120
140
0 1,000 2,000 3,000 4,000 5,000 6,000
MEAN RESERVOIR DEPTH (m)
NG
L/G
AS
, OIL
FIE
LD
S (
BN
GL
/MM
CF
G)
Main Maracaibo Basin, Assessment Unit 60990101
0
5
10
15
20
25
30
35
40
45
50
0 to <10 10 to<20
20 to<30
30 to<40
40 to<50
50 to<60
60 to<70
70 to<80
80 to<90
90 to<100
>=100
API GRAVITY (DEGREES)
RE
SE
RV
OIR
S IN
OIL
FIE
LD
S (
No
.)
Main Maracaibo Basin, Assessment Unit 60990101
0
50
100
150
200
250
300
350
400
450
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
DRILLING-COMPLETION YEAR
CU
M. N
EW
-FIE
LD
WIL
DC
AT
WE
LL
S (
No
.)
Main Maracaibo Basin, Assessment Unit 60990101
0
5
10
15
20
25
30
35
1914
1917
1920
1923
1926
1929
1932
1935
1938
1941
1944
1947
1950
1953
1956
1959
1962
1965
1968
1971
1974
1977
1980
1983
1986
1989
1992
1995
DRILLING-COMPLETION YEAR
NE
W-F
IEL
D W
ILD
CA
T W
EL
LS
(N
o.)
Main Maracaibo Basin, Assessment Unit 60990101
1
10
100
1,000
10,000
100,000
0 2 4 6 8 10 12 14 16
OIL-FIELD RANK BY SIZE
GR
OW
N O
IL-F
IEL
D S
IZE
(M
MB
O)
First third of fields discovered
Second third of fields discovered
Third third of fields discovered
Main Maracaibo Basin, Assessment Unit 60990101
0
1
2
3
4
5
6
7
8
9
1 to
<2
2 to
<4
4 to
<8
8 to
<16
16 to
<32
32 to
<64
64 to
<12
8
128
to <
256
256
to <
512
512
to <
1,02
4
1,02
4 to
<2,
048
2,04
8 to
<4,
096
4,09
6 to
<8,
192
8,19
2 to
<16
,384
16,3
84 to
<32
,768
32,7
68 to
<65
,536
65,5
36 to
<13
1,07
2
131,
072
to <
262,
144
>=26
2,14
4
GROWN OIL-FIELD SIZE (MMBO)
OIL
FIE
LD
S (
No
.)
Third third offieldsdiscovered
Second thirdof fieldsdiscovered
First third offieldsdiscovered
Main Maracaibo Basin, Assessment Unit 60990101
0
5,000
10,000
15,000
20,000
25,000
30,000
1 to
<2
2 to
<4
4 to
<8
8 to
<16
16 to
<32
32 to
<64
64 to
<12
8
128
to <
256
256
to <
512
512
to <
1,02
4
1,02
4 to
<2,
048
2,04
8 to
<4,
096
4,09
6 to
<8,
192
8,19
2 to
<16
,384
16,3
84 to
<32
,768
32,7
68 to
<65
,536
65,5
36 to
<13
1,07
2
131,
072
to <
262,
144
>=26
2,14
4
GROWN OIL-FIELD SIZE (MMBO)
VO
LU
ME
OF
OIL
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
1
10
100
1,000
10,000
100,000
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
FIELD-DISCOVERY YEAR
GR
OW
N O
IL-F
IEL
D S
IZE
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
1
10
100
1,000
10,000
100,000
0 50 100 150 200 250 300 350 400 450
CUM. NEW-FIELD WILDCAT WELLS (No.)
GR
OW
N O
IL-F
IEL
D S
IZE
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
0
10,000
20,000
30,000
40,000
50,000
60,000
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
FIELD-DISCOVERY YEAR
CU
M. G
RO
WN
OIL
VO
LU
ME
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
0
10,000
20,000
30,000
40,000
50,000
60,000
0 50 100 150 200 250 300 350 400 450
CUM. NEW-FIELD WILDCAT WELLS (No.)
CU
M. G
RO
WN
OIL
VO
LU
ME
(M
MB
O)
Main Maracaibo Basin, Assessment Unit 60990101
0
5
10
15
20
25
30
35
40
45
50
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
FIELD-DISCOVERY YEAR
CU
M. O
IL F
IEL
DS
(N
o.)
Main Maracaibo Basin, Assessment Unit 60990101
0
5
10
15
20
25
30
35
40
45
50
0 50 100 150 200 250 300 350 400 450
CUM. NEW-FIELD WILDCAT WELLS (No.)
CU
M. O
IL F
IEL
DS
(N
o.)
Main Maracaibo Basin, Assessment Unit 60990101
0
1,000
2,000
3,000
4,000
5,000
6,000
1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
FIELD-DISCOVERY YEAR
RE
SE
RV
OIR
DE
PT
H, O
IL F
IEL
DS
(m
)
Main Maracaibo Basin, Assessment Unit 60990101
0
1,000
2,000
3,000
4,000
5,000
6,000
0 50 100 150 200 250 300 350 400 450
CUM. NEW-FIELD WILDCAT WELLS (No.)
RE
SE
RV
OIR
DE
PT
H, O
IL F
IEL
DS
(m
)
Main Maracaibo Basin, Assessment Unit 60990101
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
0 1,000 2,000 3,000 4,000 5,000 6,000
MEAN RESERVOIR DEPTH (m)
GA
S/O
IL, O
IL F
IEL
DS
(C
FG
/BO
)
Main Maracaibo Basin, Assessment Unit 60990101
0
20
40
60
80
100
120
140
0 1,000 2,000 3,000 4,000 5,000 6,000
MEAN RESERVOIR DEPTH (m)
NG
L/G
AS
, OIL
FIE
LD
S (
BN
GL
/MM
CF
G)
Main Maracaibo Basin, Assessment Unit 60990101
0
5
10
15
20
25
30
35
40
45
50
0 to <10 10 to<20
20 to<30
30 to<40
40 to<50
50 to<60
60 to<70
70 to<80
80 to<90
90 to<100
>=100
API GRAVITY (DEGREES)
RE
SE
RV
OIR
S IN
OIL
FIE
LD
S (
No
.)
Main Maracaibo Basin, Assessment Unit 60990101Volumes of Discovered Petroleum
[MMBO, million barrels of oil. BCFG, billion cubic feet of gas. MMBNGL, million barrels of natural gas liquids. Fields containing less than 1 MMBO in oilfields or 6 BCFG in gas fields were not considered in the assessment. Fields were classified as oil or gas by the USGS. Fields without reported discoverydates were not included. NA means not applicable and is shown for volumes where only one field is present. Calculated values may not be equal to the
sums of the component values because numbers have been independently rounded.]
Known (Discovered) Volumes Grown (Discovered) VolumesField Type Number Number
of Fields Oil (MMBO) Gas (BCFG) NGL (MMBNGL) of Fields Oil (MMBO) Gas (BCFG) NGL (MMBNGL)
Oil Fields 45 48,209 24,169 1 46 59,108 30,398 1Gas Fields 3 0 748 25 3 0 1,050 30
Fields <1 MMBOE 11 2 1 0 10 2 1 0
All Fields 59 48,211 24,918 26 59 59,110 31,448 31
Page 1
Main Maracaibo Basin, Assessment Unit 60990101Discovery-History Sequence
[MMBO, million barrels of oil. BCFG, billion cubic feet of gas. Fields containing less than 1 MMBO in oil fields or 6 BCFG in gas fields werenot considered in the assessment. Fields were classified as oil or gas by the USGS. The first half or third shows year of first field discovery
as well as end of period. NA means not applicable and is shown where fewer than four fields are present.]
Discovery-History Sequence - Known (Discovered) VolumesFieldType Year Number of Total Mean Median
(End of Period) Fields Volume Size Size
Oil Fields Known Sizes (MMBO)First third 1914-1950 15 35,236 2,349 514Second third 1963 15 11,531 769 158Third third 1994 15 1,442 96 72
All Oil Fields 45 48,209 1,071 150Gas Fields Known Sizes (BCFG)
First third NA NA NA NA NASecond third NA NA NA NA NAThird third NA NA NA NA NA
All Gas Fields NA NA NA NA
Page 2
Main Maracaibo Basin, Assessment Unit 60990101Discovery-History Sequence
[MMBO, million barrels of oil. BCFG, billion cubic feet of gas. Fields containing less than 1 MMBO in oil fields or 6 BCFG in gas fields werenot considered in the assessment. Fields were classified as oil or gas by the USGS. The first half or third shows year of first field discovery
as well as end of period. NA means not applicable and is shown where fewer than four fields are present.]
Discovery-History Sequence - Grown (Discovered) VolumesFieldType Year Number of Total Mean Median
(End of Period) Fields Volume Size Size
Oil Fields Grown Sizes (MMBO)First third 1914-1950 15 41,986 2,799 613Second third 1973 16 14,987 937 199Third third 1994 15 2,135 142 72
All Oil Fields 46 59,108 1,285 176Gas Fields Grown Sizes (BCFG)
First third NA NA NA NA NASecond third NA NA NA NA NAThird third NA NA NA NA NA
All Gas Fields NA NA NA NA
Page 3