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New E&P Blocks of
Onshore and Offshore
Libya
Rank, Potential,
Undeveloped Fields, Discoveries, and Dry-holes
Target
Exploration
65 KENTON COURT, LONDON W14
8NW, UK.
TEL: +44 (207) 371 2240 FAX: +44 (207) 371 2240
Abstract:
To speedup your
negation process we have completed a portable update of our popular review of
the 139 new (early 2001) offshore and onshore E&P blocks of Libya utilised
666 well
records, numerous well logs, stratigraphic sections,
structural sections, and stratigraphic, geochemical, tectonic and structural
maps of Cyrenaica, Ghadames, Murzuk, Sirt, Tripolitania, and offshore Basins of
Libya, which you can load and carry into the negotiation room, and (if you
wish) buy another copy loaded into a laptop at your company’s main office back
home.
Due to the large
number of parameters, and to impartially assess, compare, and rank the E&P
potentials of the 139 blocks, one concession and well location map was drafted,
two main EXCEL© databases were compiled, and five subsidary EXCELÓ databases were
generated to summarise well records, exploration records, and geological,
geochemical, and tectonic parameters of the 139 new blocks:
Ř A
new well location map of the 139 Blocks (Scale 1/2500) was drafted to
illustrate the exploration or production status of the wells within the blocks.
Ř The
first E&P database lists drilling, engineering and geological data, status
and results of the 666 wells in all blocks (28*666 data entries). One sort
variation of the second database was generated to alphabetically list wells per
each block.
Ř
The second E&P database summarises the drilling,
engineering and geological data per block (31*139 data entries). An exploration
risk equation was modified to rank the relative E&P potential of the
individual blocks, via comparing the source, reservoirs, cap rocks, tectonics,
remaining undrilled anomalies, and exploration results of each block. Four sort
variations of the second database were generated in order to rank every one of
the new 139 blocks, and to produce 51 charts illustrating the relative E&P
ranks of the blocks of every basin-province, the relative E&P rank of the
blocks for all basins-provinces in Libya, the relative size and distribution of
the proven, probable and possible discovered hydrocarbon reserves of all
blocks, as well as other parameters not included in the ranking equation.
1.
Introduction:
Apart from the surface stratigraphic divisions,
there are no less than 20 stratigraphic nomenclatures charts for Sirte Basin
alone, for almost every one of the early operating companies has one or several
charts of the encountered subsurface stratigraphic units. Similar situations,
though to a lesser magnitudes exist for other sedimentary basins of Libya. This
E&P history produced variegated stratigraphic correlation levels, which are
hard to correlate without the actual lithologic and electric logs.
Published records of 666 wells (Figure 1) within
the new E&P Blocks of offshore and onshore Libya as published by the NOC in
early 2001 (Figure 2) were reviewed through this study, also a large number of
documents, well logs, cross-sections, and tectonic, stratigraphic, geochemical
and structural maps of onshore and offshore Libya as published in the Al Fateh
University series of conferences on the geology of Libya, (e.g. Wenneker et al
1996 and Ibrahim, 1992, 2000b, 2001a, 2001b).
The blocks are located -according to the Libyan
NOC, in six provinces. New block Ghadames 20 and a single large concession have
recently been delineated in the Kufra Basin, which is now also open for
exploration, (both are not shown in figure 2).
Fig 1
After the Libyan NOC 2000
Figure 2
The NOC’s tectonic elements map of Libya indicates
that every one of the main Libyan oil provinces can be subdivided into several
tectonic elements see table 1:
Table 1 Tectonic Elements of the Main oil Provinces of
Libya
|
1.1. Cyrenaica (Blocks C1-C12): Inverted Jabal Akhdar Basin, Cyrenaica Platform, Marmarica Trough
As-Solouq Depression. 1.2. Ghadames (Blocks G1-G20): Ghadames Basin, Al Hamra High. 1.3. Murzuk (Blocks M1-M16): Murzuk Basin, Dor El Gussa Trough and Gargaf Uplift. 1.4. Offshore (Blocks O1-O17): Sebratah Basin, Offshore Hagfa Trough, Offshore Agdabia Trough,
Benghazi Basin and Offshore Al Bottnan Basin? 1.5. Sirte (Blocks S1-S70): Hon Graben, Dor Al Abd Trough, Zella Trough, Hagfa Trough, Bu Tumaym
Trough, Ajdabia Trough, Hameimat Trough, Maragh Trough, Sarir Trough and Siwa
Basin? 1.6. Tripolitania (Blocks T1-T3): Jeffara Trough and Zamzam Trough. |
2.
Geological Input
Proven source rocks of Libya were found in the
Silurian, Devonian, Carboniferous, Triassic, Lower and Upper Cretaceous,
Paleocene and Eocene Rocks. Proven
reservoir rocks of Libya are in Basement, Ordovician, Silurian, Devonian,
Carboniferous, Triassic, Cretaceous, Paleocene, Eocene and Oligocene Rocks,
(Winnekers, 1996).
More than 30 maps showing the regional tectonic
elements, thickness, distribution and structural configuration of source,
reservoir and cap rocks of onshore and offshore Libya were updated and used in
this study, including: large scale geological map sheets of Libya, and tectonic
elements map of Libya.
Regional structural maps includes: structural
contour map of Precambrian-Cambrian Basement rocks, structural contour map of
top of Hercynian unconformity, structural contour map of top of Mesozoic rocks,
lap-out map on top of Precambrian-Cambrian Basement.
Regional isopach maps are: isopach and facies
map of the Ordovician rocks, isopach and facies map of the Silurian rocks,
isopach map of the Devonian rocks, isopach map of the Permo-Carboniferous
rocks, isopach map of the Triassic rocks, isopach map of the Jurassic rocks,
isopach map of the Lower Cretaceous rocks, isopach map of the Upper Cretaceous
rocks, facies map of the Upper Cretaceous rocks, isopach and facies map of the
Paleocene rocks, isopach and facies map of the Eocene rocks, isopach and facies
map of the Oligocene rocks, isopach and facies map of the Miocene rocks.
Regional source rock maps used are: isopach map
of proven-possible Silurian source rocks, isopach map of probable-possible
Devonian source rocks, isopach map of proven-possible Triassic source rocks,
distribution map of proven-possible Lower Cretaceous source rocks, distribution
map of proven-possible Upper Cretaceous source rocks, and distribution map of
proven-possible Paleocene-Eocene source rocks. Added to all this geochemical
source rock analysis of Upper Cretaceous formations, and play fairway maps of
several formations.
The primary source of the above information are
the regional study the regional geology team of Sirte Oil Company (Wennekers et
al., 1996), and publications in Al Fateh University series of conferences on
the geology of Libya (such as Ibrahim 1992).
3.
Using Databases to Rank E&P Blocks:
To impartially rank, and illustrate the reasons
for ranking the top most promising E&P Blocks; thirty regional source,
reservoir structural and tectonic maps of onshore and
offshore
Libya were updated, and source, reservoir and seal rocks parameters, and past
exploration results of each block were listed and plotted.
The ranking of the Block was done objectively by
using a RLATIVE E&P POTENTIAL (SCORE); which is a modified risk equation,
modified to accommodate proven reserves within the blocks. This equation can be
changed should the priorities change (e.g. gas rather than oil), on the spot.
Due to the tripartite well classification of the
Libyan National Oil Corporation (Dry, Oil, Gas, with few Suspended Wells), a
new concessions map showing the location, status (dry hole, oil well, gas well
and shows) of 666 wells, undeveloped oil and gas fields, and discoveries within
the 139 new (2001) Blocks (Scale 1/2500).
Two Basic Excel Databases were compiled:
Ř
EXCELÓ Database 1: lists data,
status and results of every well in the 139 blocks as 666*28 data entries. A
sort variation of this database (Database 1A) lists the wells per each block.
Ř
EXCELÓ Database 2: summarises
E&P data, exploration histories, geological etc. and all parameters used in
ranking the 139 New Block as 139*31 data entries.
Six sort variations of Database 2, which rank
every one of the new 139 blocks were used to produce 51 charts illustrating:
the relative E&P ranks of the blocks of every basin in database 2A, the
proven, probable and possibly discovered oil and gas reserves in dbase 2Bo and
2Bg for the entire country with charts illustrating the size and distribution
of the proven, probable and possible discovered reserves of all the blocks. These
sort variations and other variations such as database 2D, and database 2E will
be discussed below.
4. Database Number 1:
Wells, Undeveloped Fields, and Discoveries in the 139 New E&P Blocks of
Libya
Database No. 1 is an Excel Database of 666*28
cells/entries (9 to 28 entries per every one of the 666 wells in the 139 new
E&P block in onshore and offshore Libya), which summarises Target's
information, as well as published technical data on fields and wells in Libya.
All information were checked for accuracy and reliability or modified and
corrected before using them in this study. The titles of the 28 entries/well
are: New (early 2001) EPSA Block, Well Name, Longitude, Latitude, Well Number,
Original Concession, Original Operator, Location, Completion, Completion Date,
TD in Meters, Formation at TD, Results.
If the review proved that the well discovered
commercial Oil and or Gas additional entries are added: Field Name, Trap Type,
Pay (s), Reservoir Lithology, Depth of Reservoir in Meters, Net/Gross Pay Thickness,
Reservoir (s) Age(s), Oil density in °API, Reserves in
MMSTBO/TCFG, Flow Rate, Production Mechanism, Number of Wells in 1999, Number
of Producing Wells, Number of P&A Wells, Present Status of the
Field/Discovery, and Comments.
4.1. Database 1A
This is a modification of Database No. 1, in
which the wells were sorted alphabetically for each of the New E&P Blocks.
5. Database No. 2:
Ranks, Relative E&P Potentials, and Undeveloped Oil and Gas Fields and
Discoveries of the 139 New E&P Blocks in Onshore and Offshore Libya
Database No. 2 is an Excel database of 139*31
entries, which summarises all available published information, and data on
source facies, richness, and maturity, reservoir rocks facies, and the
structural configuration of on-and offshore Libya. All information was checked
for reliability and correctness before synthesis.
The titles of the 31 entries for each Block are:
New (early 2001) EPSA Block, Decimal Long. °E. of the block centre,
Decimal Lat. °N. of the block centre, Relative Prospectivity
Score (RLATIVE E&P POTENTIAL (SCORE) a modified risk equation to
accommodate proven reserves, it can be changed should priorities change, on the
spot), Area of the Block in Kms 2, Proven Oil Reserves (in MMBbls) of
undeveloped fields/discoveries if present within the block, Estimated Oil
Reserves, (to quantify Probable Oil Reserves =2 MMBbls and Possible oil
reserves =1 MMBbls), Proven Gas Reserves (in TCF) of undeveloped
fields/discoveries if present within the block, Estimated Gas Reserves, (to
quantify probable Gas Reserves =0.02 TCF and possible Gas Reserves =0.01
TCF), Total Number of Wells in the
Block, Number of Discovery and/or
Suspended Wells, Number of Delineation Wells, Number of Producible Wells.
(Wells judged to be completed as a producer), Number of Wells Which Encountered
HC Shows, Number of Dry and/or Junked Wells, Kms 2/Exploration Well (Area in Sq
Km/((Total Number of Wells in the Block+1)-Delineation Wells), Discovery / Dry
holes Ratio of the Wells in the Block= 0.1+(Discovery + Suspended Wells) / (Dry
Holes-Delineation Wells). Hence, if there are no wells or there is no discovery
in the Block 0.1 was used as the average of Libya, Proven and Potential Mature
and Spent Source Rocks (by age within charging distance), Number of Proven and
Potential Source Rocks (to quantify the relative source potential), Proven and
Potential Reservoir Rocks (by age within the block), Number of Proven and Potential Reservoir Rocks (to quantify
relative reservoir availability), Estimated Number of Undrilled Anomalies
(estimate of number of anomaly in the area - drilled wells), Estimated Maximum
Size Factor of the Undrilled Anomalies (Small (less than 100 MMBO Eq in
Place)=1, Medium (>100<300 MMSTBO Eq in Place) =1.5, and Large (>300
MMSTBO Equivalent in place)=2), Depth
of Proven and/or deepest Potential Reservoirs (in meters), Name of Nearest Field or Discovery, Number
of Nearest Fields and Discoveries, UNDEVELOPED FIELD AND/OR DISCOVERIES
WITHIN, Number of Undeveloped Fields
and Discoveries within the Block,
Distance to the Nearest Oil Pipeline (in Kms from the edge of the
block), Logistics, water depth and
Terrain, Expected Hydrocarbon (from source rocks maturity and nearby fields or
fields within the block).
Database 2 is a sequential and un-sorted
listing of the relative E&P potential per basin/area; it includes relative
E&P potential charts:
1. Ranks and relative E&P potential of the
new blocks of Cyrenaica.
2. Ranks and relative E&P potential of the
new blocks of Ghadames.
3. Ranks and relative E&P potential of the
new blocks of Murzuk.
4. Ranks and relative E&P potential of the
new blocks of Offshore Libya.
5. Ranks and relative E&P potential of the
top 25 new blocks of Sirte.
6. Ranks and relative E&P potential of the
middle 25 blocks of Sirte.
7. Ranks and relative E&P potential of the
last 25 blocks of Sirte.
8. Ranks and relative E&P potential of the
new blocks of Tripolitania.
5.1. Database 2A
This is a sort variation of Database 2, in which
the new blocks of each basin were sorted according to their relative E&P
potential per basin/area. This Excel database includes the following relative
E&P potential charts:
9. Ranks and relative E&P potential of the
new blocks of Cyrenaica.
10. Ranks and relative E&P potential of the
new blocks of Ghadames.
11. Ranks and relative E&P potential of the
new blocks of Murzuk.
12. Ranks and relative E&P potential of the
new blocks of Offshore Libya.
13. Ranks and relative E&P potential of the
top 23 new blocks of Sirte.
14. Ranks and relative E&P potential of the
middle 23 blocks of Sirte.
15. Ranks and relative E&P potential of the
last 24 blocks of Sirte, shown in figure 3.
16. Ranks and relative E&P potential of the
new blocks of Tripolitania, shown in figure 4.
Fig 3 47 70
Fig 4
5.2. Database 2Bg
This is another sort variation of Database 2 in which
the Blocks were sorted according to their proven, probable and possible gas
rather than oil reserves in all of the 139 blocks. This variation of Database 2
includes chart:
17. Proven, probable and possible discovered Gas
Fields in all 139 new blocks, Libya, figure 5.
Fig 5
5.3. Database 2Bo
Another sort variation of Database 2, in which
the Blocks were sorted according to their proven, probable and possible oil rather
than gas reserves in all of the 139 blocks, it includes chart:
18. Proven, probable and possible discovered Oil
Fields in all 139 new blocks, Libya, figure 6.
Fig 6 1
31
5.4. Database 2C
Another variation of Database 2, in which the
Blocks were sorted according to their relative E&P potential. This Database
includes the following charts:
19. Relative ranks and E&P Potential of the
139 new blocks, Libya.
20. Relative E&P potential of the first 20
new blocks, Libya.
21. Relative E&P potential of the second 20
new blocks, Libya.
22. Relative E&P potential of the third 20
new blocks, Libya.
23. Relative E&P potential of the fourth 20
new blocks, Libya.
24. Relative E&P potential of the fifth 20
new blocks, Libya.
25. Relative E&P potential of the sixth 20
new blocks, Libya.
26. Relative E&P potential of the last 19
new blocks, Libya, figure 7.
Fig 7
27. Block area vs.
relative E&P potential of the 139 new blocks, Libya (Area in Km2).
28. Block area vs.
relative E&P potential of the 139 new blocks, Libya (Blocks).
29. Total number of
wells vs. relative E&P potential of the 139 new blocks, Libya.
30. Well / Kms vs.
relative E&P potential of the 139 new blocks, Libya.
31. Discovery / dry
hole ratio vs. relative E&P potential of the 139 new blocks, Libya.
32. Number of
remaining undrilled anomalies vs. relative E&P potential of the 139 new
blocks, Libya.
33. Average depth of
primary reservoirs (in m) vs. relative E&P potential of the 139 new blocks,
Libya.
34. Distance to
nearest oil pipeline vs. relative E&P potential of the 139 new blocks,
Libya.
35 Number of
discovered oil and gas fields vs. relative E&P potential of the 139 new
blocks, Libya.
36. Discovered oil
reserves (MMSTBIIP) within the Blocks VS relative E&P potential of all new
blocks.
37 Number of proven
and potential Source Rocks vs. relative E&P potential of the 139 new
blocks, Libya.
38. Number of proven and potential Reservoir
Rocks vs. relative E&P Potential of the 139 new blocks, Libya.
39. Maximum size Factor of the remaining
undrilled anomalies VS relative E&P potential of the 139 new Blocks, Libya.
5.5. Database 2D
This
is another variation of Database 2C, which is showing the relative maximum size
factors (MSFs) of remaining undrilled structural anomalies (RUAs) within each
Block. This was done to highlight blocks with potential for undiscovered giant
oil and gas fields. This database includes charts:
Fig 8