global Exploration Update

GEO ExPro, together with IHS, presents some of the most significant ­discoveries made throughout the world in recent months.

Jane Whaley, Associate Editor. Robert Copson, Editor, Daily Alert, IHS Defining a new province

After two promising discoveries in deep - in the adjacent Tano license, 5.3km south- water off Ghana, oil companies working west and down dip from Mahogany-1. in the area were further encouraged by Hyedua-1 was drilled in 1,530m water Cartography: GEO ExPro the success of the most recent new field depth to a TD of 4,002m and encountered wildcat. Odum 1 was drilled on a new pros- 40m of net pay in a Cretaceous sandstone pect in the Tano Basin, about 13 km east of reservoir. The oil encountered is light (37° the previous finds in the West Cape Three API) and has a favourable gas oil ratio. It The Cassra discovery is on trend with a number of Points block, 51km from the Ghanaian coast appears that both these wells have drilled a other finds in the Tobago Trough. in 955m of water. Kosmos Energy, opera- single large structure with high quality res- tor of the block, announced that the well, ervoirs in Santonian turbidite sandstones. Extending the play which terminated at a depth of 3,387m, This was recently named as the Jubilee discovered a 60m gross oil column, includ- Field, and is thought to have potential in- In early January, 2008, the Canadian inde- ing 22m net of oil-bearing, stacked reservoir place reserves of 1.3 Bbo (207 MMcm) of pendent oil company Petro-Canada con- sandstones. Testing suggests that this oil is light (37° API) oil. The latest P50 reserve firmed a significant gas find in deep water high quality with an API of 29°. The reservoir number given by Tullow is 480 MMbo. (> 400m), about 25 km to the north of is thought to have been deposited in a large Field development studies are underway the island of Tobago in the Caribbean. fan or channel systems in Upper Cretaceous to ensure speedy production, and a 3D/4D This discovery, Cassra 1, is located 18.5km Campanian times, trapping hydrocarbons seismic survey was run over the area late in north-east of the Iris discovery and is on stratigraphically. 2007. At least five further appraisal wells are trend with a number of other significant Kosmos, a privately held international oil planned on the field in order to increase the discoveries in the Tobago Trough to the exploration and production company which proven resource and to collect additional north of Trinidad and Tobago. In total this focuses on West Africa, first identified the geological and engineering data to assist in trend, sourced from Cretaceous La Luna play with its Mahogany 1 well, which was development. equivalent rocks, is thought to contain an drilled in June 2007. This discovery, 63km The Odum discovery can therefore be estimated 5Tcf (142 MMm3; 900 MMboe) of from the coast in waters of 1,320m, was considered confirmation of a new, signifi- proven gas reserves. confirmed in August 2007 by Tullow Oil’s cant oil province in Ghana’s western off- The well, in Block 22 in the West Tobago Hyedua 1 well - pronounced ‘shed-you-a’ shore basin. sub-basin, targeted the edge of a large seis- mic anomaly estimated to cover 68 sq km and reached a total depth of 1,712m below sea level. It found a gas water contact at the reservoir objective and on testing it flowed gas at a rate of 23 MMcfg/d (650 Mcmg/d). Petro-Canada announced that, based on the well results and using local field analogue recovery factors, they con- sidered that the discovery could contain in the range of 0.6 to 1.3 Tcf (17-37 Bcm; 107-233 MMboe) of recoverable gas. To appraise the discovery further, in late January Petro-Canada commenced drilling a second Cassra well a few kilometres to the south of the original well. According to Petro-Canada, which is 90% owner as well as operator on Block 22, there are a number of other promising prospects within the acreage. It is believed that Petro- Canada has invested more than $80 million ©IHS in the blocks offshore Trinidad and Tobago. Odum is the third promising discovery to be made in deep water off Ghana in the last year.

58 GEO ExPro April 2008 New Barents Sea Discovery

In early March this year StatoilHydro results from the well show that the reservoir announced that their well 7222/6-1S in contains both oil and gas in mid Triassic the south-western Barents Sea had found sandstones. No well tests were carried out hydrocarbons. The well, approximately 175 but extensive data acquisition and sam- kilometres north-west of the northern Nor- pling was undertaken. The company, which

wegian town of Hammerfest, was plugged is the operator and has 100 percent interest Photo: Halfdan Carstens and abandoned at 2,825 m in the Lower in licence 228, announced that it is too early Triassic. to estimate the size of the finds. Further StatoilHydro had been targeting a Trias- data processing is required, but they con- sic prospect, known as Obesum, and the sider the discovery promising and will drill

The gas from Snøhvit is liquefied at Melkøya just outside Hammerfest in northern Norway and sent to markets in Europe and the US.

another well in the licence in 2008. The Norwegian Directorate puts total undiscovered resources in the Barents Sea at 6.2 Bboe (990 MMm3), with an uncertainty range between 2.8 and 10.7 Bboe. Oil in place is about 1.25 Bboe. Since 1980 there have been a number of discoveries in the Barents Sea, but only one has been large enough to start production. The Snøhvit field, put on production last year, has a 124m gas column overlying a 14 m thick oil leg in Lower and Middle Jurassic formations. The Goliat discovery, made in 2000, found oil and gas in sandstones of the © Fugro/TGS Realgrunnen Group (Middle Jurassic-Upper Seismic line running from Obesum into the Hammerfest Basin further south. The sedimentary package Triassic). Both these fields are about 100km through the well consists of Triassic and Paleozoic sedimentary rocks. Courtesy of Fugro/TGS. to the south of the Obesum discovery.

Boosting Brazilian reserves

A huge gas-condensate field, to be called to image. The well was drilled to a total Jupiter, has been found offshore , depth of 5,252m and encountered 120m 290km south of , according to of reservoir, having drilled through about , Brazil’s state-controlled oil com- 2,000m of salt. pany. The discovery is just 37km (23 miles) Petrobras believe that the Jupiter Field from the giant Tupi Field, discovered in 2006, Cartography: GEO ExPro could be as large as Tupi, although further which is estimated to contain between five work needs to be done to delineate it, and and eight billion barrels of light oil with an a number of appraisal wells are planned in API of 28° and the gas:oil ratio of approxi- the near future. mately 15-20%. The Tupi reservoir is a new Recent large discoveries Tupi and Jupiter are Brazil is hoping that these discoveries carbonate facies previously unknown in indications of the potential of the sub-salt trend are just the ‘tip of the iceberg’ for the sub- Brazil and it has been suggested that it may in the salt play, which appears to extend south- be analogous to the Toca carbonate trend westwards from the Espirito Santo Basin in the Congo Basin. Janeiro. It is in ultradeep water of between through the to the Santos The discovery well, which completed in 2,000m and 2,500m. Like the Tupi field, the Basin. It has been estimated that potential mid-January 2008, is a new field wildcat well targeted the Aptian Guaratiba carbon- new reserves from this trend could be as in the south-eastern part of the Santos ate formation below the widespread salt, high as 56 Bboe, which could boost Brazil’s Basin, a large offshore basin lying along the which until recent technological develop- oil reserves from the 17th biggest in the coast of the states of São Paulo and Rio de ments in seismic imaging was very difficult world to among the top 10.

GEO ExPro April 2008 59 global Exploration Update Huge Bids for Old Prospects

2006 Chukchi Sea Assessment Province and Alaska OCS 144° 148° 152° 156° 160° 164° 168° 172° 176° 180° 176° 172° 168° 164° 160° 156° 152° 148° 144°140° 136° 132° 128° 124° 120° 116° 112°

72°

Shell and ConocoPhillips s EXPLANATION r e t s a 60° r 70° Planning Area and Assessment e W Province Boundary t a n a i W s are the big spenders in Oil Field Gas Field n s BARROW a u She i l d R f Edg U.S. Federal Outer Continental e a 68° Shelf and Areas of Conventional n Potential for Technically a RUSSIA C 58° Recoverable Oil and Gas National Petroleum the $2.6 billion Sale 193 Reserve - Alaska ©MMS - Alaska Division Arctic National Chukchi Sea, Alaska with Wildlife Refuge 66° 56° T 64° A P the highest bids over pre- NOME S FAIRBANKS CANADA viously drilled prospects. 54° ALASKA 62°

ters 60° Wa 52° sian us BETHEL ANCHORAGE This highly prospective R VALDEZ

58° MIDDLETON IS. JUNEAU

50° S area is a continuation of helf E dge 56° . IS K IA S D O h K e lf the prolific Alaska North 48° E d g e 54°

s ter Slope petroleum system Wa n 46° Shelf Edge dia na 52° Ca

50 0 150 NAUTICAL MILES where Prudhoe Bay and 50 0 150 MILES 50 0 150 KILOMETERS other super giant fields 44° 50° 174°

178° 176° 174° 170° 166° 162° 158° 154° 150° 146° 142° 138° 134° have been discovered. SherwoodLocation\.....\Figure Chuk-01-Chukchi of Chukchi Index Map.cdr Sea planning area and assessment province. Figure 1. Location of Chukchi Sea Planning area and assessment province.

Thomas Smith, Associate Editor Chukchi Sea Province Summary-2006 Assessment 20 What a surprise for the Minerals Manage- and geochemical data were collected in says Curtis Smith, Shell’s spokesman in Alas- ment Service (MMS) that had estimated it preparation for the 1988 and 1991 lease ka. “Our entry into the Chukchi, combined would make $67 million off the Chukchi Sea offerings. Five wells were drilled between with our lease holdings in the Beaufort Sale when all the top 10 bids each exceeded 1989 and 1991; the Burger, Klondike, Crack- Sea, further solidifies our position in Alaska, that amount. erjack, and Popcorn encountered recover- which has the potential to become a new Shell was by far the largest bidder win- able hydrocarbons, while the Diamond well 156° 158° 75° 169° 162° 160° ning 275 tracts for over $2.1 billion, and was the only one to possibly miss. 75° 168° 165° all 10 of the highest bids were theirs, while Shell’s Burger well encountered the larg- Chukchi Sea Planning Area N

il & 74° le O Ga 3, ConocoPhillips won 98 tracts for the sum est accumulation and this time received ib s 70 P 0 74° lig o m g te Is (1 e n o 2, N 5 ba 21 0 t th 0 A i 0 a ft)

E m I l s total of $506 million. The largest bids went the highest bids. In 2001, a re-appraisal by S o 10 ( 1 I 0 b m , a 6 H (3 Is 3 t 5 o 0 h C b f 0 ath t) K f t a e ) U n n for the Burger prospect, previously drilled James Craig and Kirk Sherwood, geologists n ri © MMS - Alaska Division a H a n H m o 73° C b y u n S a N 73° C

A

I by Shell in 1989-90. Five other operators with Minerals Management Service (MMS), S

S

U

R also won tracts in this sale. Alaska Division, estimated the trap closure Gas Potentia l & l Oi to cover 765 km² as the well encountered th 72° 72° i W Barrow Exploration History d POPCORN Submarine gas shows in a 33m thick Cretaceous sand- e Point Canyon arrow s B s t i Barrow e m i CRACKERJACK L s e l In 1988 and 1991, four lease sales (2 sales stone at 1,695 m. Condensate and gas were i DIAMOND - ° s M BRONTO 71 BURGER klin - Point Fran e SAURUS re A h R. 71° T u ar SKULL In a each of those years) were held in different recovered from formation sampling devic- Peard CLIFF e Bay t M r ainwrigh W D e PEAR a Atqasuk d KLONDIKE e A Icy KUGRUA K

u R k parts of the Chukchi shelf with Shell as the es, however the well was never flow tested. Cape . R

. TUNALIK 70°

) 156° s r primary industry investor. Of the 42 pros- The most likely estimated resource is 14 Tcf e ° 70° t luk AOLAK 159 a Kasega K W Lagoon e t a t TUNGAK CREEK S

(

t i PLUGGED AND ABANDONED WELL

m

pects the MMS had identified on the shelf, (0.4 Tm³; 2.5 Bboe) gas and 724 MMb (115 i Point Lay L

e AREA OF RESOURCE POTENTIAL l i (2006 ASSESSMENT) M

- e BATHYMETRIC ISOBATH (METERS) e r h . 85% of the previous bids went to just five MMm³) of condensate, however, Craig and T R Ledyard Bathymetry from Perry and Fleming, 1990 69° Bay AKULIK Cape 69° Lisburne Chukchi Sea P itm prospects all of which were then drilled. All Sherwood admit the volumetric estimates k e g u EAGLE CREEK ea r w o . p R R. k u 68°30' K ALASKA ik ew . leases had 10- year terms that expired prior for the pool are highly speculative based on Ip R 68°20' k kpu Point Hope Ku

165°00' to this lease sale. Many leases had been just one well. 68° 68° 0 50 Nautical Miles 0 50 Statute Miles 168°00' 167°00' 166°00' 164°00' 163°00' 162°00' 0 50 Kilometers Sherwood\....\Figure Chuk-02-Chukchi Location Map.cdr dropped before expiration dates to allow Figure 2. Location of continental shelf area with the Chukchi Sea Panning Area assessed as offering potential for companies to take write-offs for leasing and New Optimism technicallyThe Chukchirecoverable oil and gas Sea in 2006 leaseassessment. area off the north west coast of AlaskaChukchi Sea where Province Summary-2006 5 offshore Assessment wells have exploration expenses. “The Chukchi Sea is believed by many to be been drilled and is considered21 by the Minerals Over 160,000 km of high quality seismic one of the most promising undeveloped Management Service (MMS) to have high oil and data, as well as gravity, magnetic, thermal hydrocarbon basins in the United States,” gas potential.

60 GEO ExPro April 2008 U.S. Department of the Interior Minerals Management Service MMS Alaska OCS Region 169°0'0"W 167°0'0"W 165°0'0"W 163°0'0"W 161°0'0"W 159°0'0"W 157°0'0"W NS04-06 NS02-06 NS03-05 NS03-06 NS04-05 Successful companies N " 0 '

0 in the recent Chukchi ° 3 N 7 " 0 ' 0 ° 3 7 Arctic Ocean lease sale.

NS04-08 NS02-08 ea NS04-07 NS03-07 i SNS03-08

h N

c " 0 k ' 0

u ° © MMS - Alaska Division 2

N h " 7 0

' C 0 ° 2 7

NR03-01 NR04-02 NR02-02 NR04-01 # N " 0 '

0 winning 16 tracts and bidding almost $14 over 8 Tbo (1.3 Tm³). The US Geological Sur- ° 1 N " 7 0 ' Barrow 0 °

1 NR03-02 Peard Bay 7 million. Their leases are located on pros- vey estimates a recoverable hydrocarbon

##Wainwright NR03-03 NR0#4-04 pects outside the areas that have been endowment of 71.3 Bboe of which about Atqasuk NR02-04 NR03-04 NR04-03 # drilled. “Alaska is a new and exciting play for 40% or 28.8 Bboe have already been dis- N " 0 ' 0 ° N 0 " 7

0 Icy Cape ' 0 °

0 National Petroleum StatoilHydro,” says Kjersti Torgersen, head covered. 7 Reserve - Alaska # of communication for StatoilHydro North In 2006, the MMS assessed 29 explora- Point Lay Legend NR02-06 NR03-05 NR03-06 America. “We believe the area is both oil and tion plays in the Chukchi Sea OCS area. High Bid Companies N " 0

ConocoPhillips Company ' 0 ° N 9 " 6

0 gas prone,” she adds. They arrived at an expected or mean value ' Eni Petroleum US LLC 0 ° 9 6 Iona Energy Company (US) NACRA for technically-recoverable, undiscovered Repsol E&P USA Inc. Shell Gulf of Mexico Inc. NR02-08 Alaska Maritime National Huge Potential-Complex Geology hydrocarbon energy of 29 Bboe (4.6 Bm³) NR03-07 Wildlife RefugeNR03-08 StatoilHydro USA E&P, Inc. ## Point Hope Official Protraction Diagram N " 0 ' MMS mapping of the area show 5 distinct ranging up to 77 Bboe (12 Bm³). Free oil and 0 ° N Submerged Lands Act Boundary " 8 0 6 '

0 0 25 50 100 Miles ° 8 6 Cape Thompson basins with deformation ranging from sim- condensate estimates range from 15 Bb (2.4

# # 168°0'0"W 167°0'0"W 166°0'0"W 165°0'0"W 164°0'0"W 163°0'0"W 162°0'0"W 161°0'0"W 160°0'0"W 159°0'0"W 158°0'0"W ple listric faulting to a fold and thrust belt. Bm³) to 40 Bb (6.4 Bm³). heartland for Shell.” They have an inventory of 856 mapped After the previous sales, evaluation of Shell is responsible for 4 of the 5 wells prospects (from conventional 2-D seismic the Chukchi Sea was certainly curtailed by drilled in the Chukchi offshore area and data) that include anticlines, fault traps, and the industry downturn that occurred in has been gathering seismic data for nearly stratigraphic wedge-outs. Eleven of these the early 1990’s. We currently have much two decades. They have been evaluating prospects exceed 607 km², larger than the higher oil and gas prices, tried and proven the subsurface geology for the last 4 years major oil fields of the Alaska North Slope. Arctic production technologies, and a very that included reprocessing an extensive Most of the source rocks present in optimistic view among the bidders. While 2-D seismic data set and have two seasons northern Alaska were penetrated by the 5 it is too early to project about new seismic of new proprietary 3-D seismic. This effort exploration wells drilled here. The Klondike programs and wells, this area is certain to has allowed Shell to complete a state of well penetrated the most complete sec- receive a much more aggressive evaluation the art geologic tectonic plate reconstruc- tion encountering fair to excellent oil-prone this time around. tion of the Arctic and compile an extensive units 314 m thick. Kirk Sherwood of MMS regional study to “underpin the confidence estimates that one of these source beds in opportunities in the area.” (Triassic Shublic equivalents) could have “We have done our homework here, using created nearly 3 Tbo (0.5 Tm³). Across the current technology and current climate con- entire northern Alaska petroleum province, In the next issue of GEO ExPro we will look at ditions to evaluate possible development this same system could have generated the Russian part of the Chukchi Sea. scenarios, pending exploration success,” BROOKIAN SEQUENCE BASINS AND PLATFORMS says Curtis. “We plan to use extend reach 174° 172° 170° 168° 166° 164° 162° 160° 158° 156° 154° 152° 150° 148° 146° 144° 142° 140° 138° 136° drilling that enables a smaller footprint and 73° 100 m NORTH N IN CHUKCHI fewer platforms with fewer supply vessels. 72° OR S TH A HIGH TERTIARY CH I B We have developed ice-reinforced devel- UKCH N

s U s r CRETACEOUS r e I POPCORN W e t t © MMS - Alaska Division opment plans pioneered from our work at a H M U a W C R K W 72° n n a K O B a other Arctic sites like Sakhalin (a far eastern i i s CRACKER- A F d s U a u T JACK S H n R I A N a Russian island).” - C DIAMOND a L C e -

S P a i N KLONDIKE A Barrow CABOT e BURGER KAKTOVIK BASIN S ConocoPhillips spokesperson Erec Isaac- h Ed 50 70° c F g R 0 t e r k ol C Hin m d BARROW g o u b e e N T Li f h l I ne t u son, VP Exploration and Land for Cono- F E C WALAKPA C o dg a l P e d e Wainwright L be A MUKLUK GALAHAD B H lt T coPhillips in Alaska, seemed pretty excited E F SIMPSON MARS HAMMERHEAD R O BELCHER A R KUVLUM L M LIBERTY 70° after the sale as high bidder on 98 tracks D FISH CREEK Nuiqsut CORONA AUR- Point MEADE T PRUDHOE ORA H CO Lay N E ALPINE L dg KUPARUK K.I.C. #1 and with their optimistic outlook there, R V e IL Fol BADAMI U L db E OUMALIK elt S B SQUARE LAKE T they should be. “The Chukchi is an exten- T AS UMIAT RANGE FRON IN WOLF GUBIK S 68° CREEK KEMIK K NPR-A CO EAST sion of the same prolific petroleum system Point LV O ILL UMIAT O ANWR Hope E B R ASI B that produced the Kuparuk, Alpine, and N C HO A P OOKS RANG A N R E L E B A A 170° B F D A R S A Prudhoe Bay fields, says Erec Isaacson. “Both S O K 68° IN NT A

( U

E .

S GAS . the Klondike and Burger discoveries are ) EXPLORATORY OIL N FIELD I WELL, P&A FIELD L analogs to the established plays at Kuparuk SEISMIC PROFILE E P 50 0 150 I and Alpine.” MILES P 50 0 150 L KILOMETERS I For Norwegian oil company giant, Sta- O Sherwood\...\Figure Chuk-08-Brookian Basins.cdr 160° 150° 140° toilHydro this is their first move into AlaskaFigure Brookian 8. Brookian sequence sequence depositional depositional systems and systems tectonic setting, and tectonicArctic Alaska setting, and Arctic Arctic offshore. Alaska and Arctic offshore.

Chukchi Sea Province Summary-2006 Assessment 27 GEO ExPro April 2008 61