EXPLORATION Multi-client seismic spurs interest The Northeast Shelf,with several giant fields already discovered and put on production,is recognised as a world-class petroleum province.New seismic acquired in the rest of the Sea of Okhotsk indicate that there is more to be found.

Dalmorneftegeofizica

Courtesy of TGS has acquired a huge seismic data base covering almost the entire Sea of Okhotsk. New, modern data is now made available through a cooperati- on with TGS Nopec. Photo: Erling Frantzen Courtesy of TGS

BP/Rosneft Pela Lache

OKHA

SAKHALIN

Yuzhno-Sakhalinsk

The Sea of Okhotsk is named after Okhotsk, the first Russian settlement in the Far East. It is the northwest arm of the Pacific Ocean covering an area of 1,528,000 sq km, lying between the Kamchatka Peninsula on the east, the Kuril Islands on the southeast, the island of Hokkaido belonging to to the far south, the island of Sakhalin along the west, and a long stretch of eastern Siberian coastline along the west and north. Most of the Sea of Okhotsk, except for the area around the Kuril Islands, is frozen during from November to June and has frequent heavy fogs. In the summer, the icebergs melt and the sea becomes navigable again. The sea is generally less than 1,500m deep; its deepest point, near the Kuriles, is 3,363 m. Fishing and crab- bing are carried on off W Kamchatka peninsula. The DMNG/TGS Seismic acquired in 1998, 2004 and 2005 is shown in green, blue and red colours. Note also the location of Okha where oil seeps were found 125 years ago.

On the shelf of the Sea of Okhotsk, mainly off the coast of Sakhalin, the world's largest oil companies are actively exploring for and exploiting oil and gas resources together with several Russian companies. The regi- on is highly productive and exceptionally important for fisheries.

GEO ExPro October 2005 35 EXPLORATION

Halfdan Carstens

Oil and gas have been produced in the

North Sakhalin Basin since 1927 from a lar- Courtesy of TGS ge number of small onshore fields. Offsho- re,giant discoveries have been made in the same basin, and this has spurred the inte- rest for exploring in other sedimentary basins offshore Sakhalin. This interest is now reaching further out, to the rest of the SeaofOkhotsk as more seismic data is acquired and interpreted. TheSea of Okhotsk thus represents another example where non-exclusive seismic data is a key tool to explore in a frontier area, the principle being that of dispersing cost and risk amongst several oil companies. "The challenge in the case of Sea of Okhotsk lies with central and local Russian Seismic line through the Lunskoye gas-condensate field offshore Sakhalin shows the gas cloud above the authorities. It is important that the terms proven field and channel deposits immediately to the east, not imaged on older vintage seismic in the area. permit and stimulate non-exclusive data acquisition: All parties will benefit. Russian seismic contractors will play an important This encouraged the first exploration dril- had been discovered. role, and Russian authorities will experien- ling in the 1890’s, but it was not until 1923 Offshore exploration began in earnest in ce higher interest and increased competiti- that the Sakhalin Trust struck oil and disco- 1968 with the drilling of a deviated onsho- on for exploration acreage," says Kjell vered the Okha field (compare map) that re well into the offshore region. Modern Trommestad, Vice President and General began producing four years later. activity was initiated during the first half of Director Europe of TGS NOPEC. During the next 40 years eight new the 1970's, first through a co-operation fields were discovered, and by the end of between and Japanese com- First onshore – then offshore the 1950’s all of the large anticlines map- panies, followed by a phase of activity by Exploration on the Sakhalin Island dates ped onshore had been tested to depths of Russian companies alone, and eventually back more than 100 years, to 1879, when a 2.5 km.Deeper targets were thereafter dril- the entrance of international exploration local hunter found oil lakes and numerous led based on seismic data. By 1971, a total companies came in the late 1980’s and ear- oil seeps near Okha on the northeast coast. number of 35 onshore oil and gas fields ly 1990’s. Marine drilling did not begin until 1977. "From 1977 to 1989, 22 wells were drilled and a number of significant oil and gas dis- coveries were made offshore Sakhalin, including Odoptu (1977), Chaivo (1979), Lunskoye (1984), Piltun-Astokhskoye (1986) and Arkutun-Dagi (1989)," says Deputy Director Vladimir Kudelkin of Dal- morneftegeofizica Trust, which is head- quartered in Yushno Sakhalin on the Sak- halin Island. During the next few years, in the early 1990’s, an aggressive exploration cam- paign followed both inside and outside the main fairway. A number of structures were drilled on the northeastern shelf, the southwestern shelf and the western shelf. TheAniva Bay and the Terpeniya Bay were also tested. "The five wells drilled were all dry.The main reason for this was that there were no reservoirs," says Kudelkin. World-class province "Exploration in the Sea of Okhotsk has toalarge extent been limited to the areas

36 GEO ExPro October 2005 to opening of new areas for exploration and subsequent development offshore north Sakhalin," says Trommestad who has seen the modern seismic data in the Sea of Okhotsk acquired by TGS NOPEC in coope- Photo: Halfdan Carstens ration with DMNG." Excellent petroleum system TheSea of Okhotsk is a large marginal sea located at a triple junction with the Eurasian Plate to the north, The Pacific Pla- te to the south and the North American Plate to the east.The larger part of the Sea of Okhotsk is occupied by the Okhotsk sub-plate, which suffered several rifting phases during Tertiary times: in Eocene- Oligocene, Middle Miocene and Pliocene. TheKamchatka and Sakhalin orogenic systems were formed along collision boun- daries of the Okhotsk sub-plate due to transpression regime. "More than twenty discrete petroleum basins are present in the Sea of Okhotsk, Vladimir Kudelkin is Deputy and the depocentres have several similari- Director of Dalmorneftege- ofizica Trust (DMNG) and ties. The region may therefore considered has been involved in explo- ration in the Sea of Okhotsk for more than 20 years. DMNG and TGS NOPEC offshore Sakhalin. Offshore production the above mentioned discoveries are loca- started in 1999 and is taking place from the ted. ThePela Lache well drilled by Ros- Dalmorneftegeophizica (DMNG), a North Sakhalin Basin where prospectivity neft/BP in Sakhalin V in 2004 represents Russian seismic company based in Yuzh- is related to a combination of excellent the first step outside the established fair- no-Sakhalinsk, and TGS-NOPEC Geophy- reservoir rocks, effective seals and simple way," says Trommestad. sical Company (TGS), a Norwegian/Ame- rican company specialising in multi-client structures," says Kudelkin. In 1998, BP formed an Alliance with Ros- seismic have jointly carried out a number "This has established offshore Sakhalin neft to explore in Sakhalin via an exclusive of multi-client seismic projects throug- as a world-class hydrocarbon province. bidding agreement (BP 49%, Rosneft 51%). hout the world for more than 10 years. Accumulated reserves are in excess of 5.5 In June 2002, Rosneft obtained the first During the last 6-7 years, the multi-client 3 billion barrels of oil and 35 trillion ft (6.3 exploration licence on behalf of the Allian- concept has also been successfully imple- billion barrels of o.e.) of gas. Dalmornefte- ce for the rights to explore Kaigansky– mented in the Sea of Okhotsk in the Far geofizica has estimated the oil and gas Vasukansky blocks in the south of the Sak- East . This activity has played a sig- resources in place to be in excess of 90 bil- halin V area, which had no previous explo- nificant role in the exploration for oil and lion barrels of oil equivalents. In compari- ration history. gas in this region. son, total accumulated production on the The first well in the block "encountered UK continental shelf is in the order of 30 significant volumes of oil and gas in a num- billion barrels of oil equivalents." ber of high quality sandstone reservoirs," As offshore exploration has been very according to BP. It was drilled "farther limited we expect that many major disco- north, farther offshore (49 kilometres), and veries will be made in the future," Kudelkin in deeper water (114 metres) than any pre- adds. vious well offshore Sakhalin. This well Current investors in the area include marks the first drilling activity in the major oil companies like BP, ChevronTexa- modern stage of Sakhalin oil and gas co, ExxonMobil, Rosneft, Shell and TNK-BP. exploration." "The results of Pela Lache -1 represent a Stepping out positive first step towards opening a new "Despite the established prospectivity area for exploration and subsequent deve- of the region, offshore exploration activity lopment offshore northern Sakhalin," BP Photo: Erling Frantzen has so far been restricted to a narrow corri- said. "This is a first confirmation of a prolific DMGG’s premises in Yushno Sakhalin. dor east of the Sakhalin Island, where all of trend extending to the east and could lead

GEO ExPro October 2005 37 EXPLORATION

Location Map - Sakhalin Island Sakhalin Island

Scale1:814000 Projection: Longitude/Latitude Datum: WGS 84 SHOM11257NPSHOM11257NP The Sakhalin-1 project Blocks Pipelines Sakhalinskiy Zaliv Unlicenced Gas

Licensed Oil Fields Proposed Gas The Sakhalin-1 project includes three Oil Proposed Oil Sea of Gas Miscellaneous Russia Okhotsk Gas Condensate Cities offshore fields: Chayvo, Odoptu, and Ark-  LNG Terminal  Platforms/ BP discoveries Proposed Platforms KOLENDOKOLENDO SEV SEV Sakhalin utun Dagi. Exxon Neftegas Limited is the Island Produced using Third Party Supplied Data, June 2004. KOLENDOKOLENDO SHOM11246NPSHOM11246NP ©2004 Deloitte & Touche LLP SHOM11246NPSHOM11246NP operator for the multinational Sakhalin-1 OKHAOKHA SEV SEV Piltun-Astokhskoye Field NEKRASOVKANEKRASOVKA Tatarskiy OKHAOKHA TSENTRALNAYA TSENTRALNAYA ASTRAKHANOVSKAYAASTRAKHANOVSKAYA Proliv Moskalvo Okha KAYGANSKOYEKAYGANSKOYE VOST VOST

OKHAYUZHOKHAYUZH

EKHABIEKHABI EKHABIEKHABI VOST VOST GILYAKO-ABUNANGILYAKO-ABUNAN Consortium. Co-venturers include the ODOPTU-MOREODOPTU-MORE ODOPTU-MOREODOPTU-MORE Vostochnyy ASTRAKHANOVSKOYEASTRAKHANOVSKOYE SAKHALINSAKHALIN I I - - ODUPTUODUPTU ODUPTUODUPTU ABANOVSKOYEABANOVSKOYE UZLOVOYEUZLOVOYE VOLCHINKAVOLCHINKA TUNGORTUNGOR ODOPTUODOPTU ODUPTU-MOREODUPTU-MORE VOLCHINKAVOLCHINKA Zaliv PILTUN-ASTOKHSKAYA 14 SHKHUNNOYESHKHUNNOYE NELMANELMA Terpeniya Japanese consortium SODECO (30 per-  VOLCHINKAVOLCHINKA ERRIERRI ZAP ZAP ODOPTU-MOREODOPTU-MORE SAKHALINSAKHALIN II II - - PILTUN PILTUN ERRIERRI SAKHALINSAKHALIN I I - - PILTUN-ASTOKHSKAYA 13 ODUPTUODUPTU  SABOSABO GLUKHARSKOYEGLUKHARSKOYE SEV SEV OSINOVSKOYEOSINOVSKOYE PILTUN-ASTOKHSKAYA 8 PA-BPA-B  SABOSABO ZAP ZAP cent); affiliates of Rosneft, the Russian sta- PILTUN-ASTOKHSKAYA 6 BEREZOVSKOYEBEREZOVSKOYE  7 PILTUN-ASTOKHSKAYA 7 ODOPTU-MOREODOPTU-MORE PILTUN-ASTOKHSKAYA 16 KYDYLANIKYDYLANI MALOYEMALOYE SABO SABO PILTUN-ASTOKHSKAYA 11 GYRGYLANIGYRGYLANI  SAKHALINSAKHALIN II II - - PILTUN PILTUN te-owned oil company, RN-Astra (8.5 per- KRAPIVNENSKOYEKRAPIVNENSKOYE MUKHTINSKOYEMUKHTINSKOYE KENIGAKENIGA PA-BPA-B YUZHYUZH PILTUN-ASTOKHSKAYA 9 PILTUN- PILTUN-ASTOKHSKAYA 12  ASTOKHSKAYA 18  PILTUN-ASTOKHSKAYA 5 PAROMAYPAROMAY PILTUN-ASTOKHSKOYEPILTUN-ASTOKHSKOYE cent) and Sakhalinmorneftegas-Shelf (11.5 2-UNDEV2-UNDEV

PILTUN-ASTOKHSKOYEPILTUN-ASTOKHSKOYE 2-UNDEV2-UNDEV PILTUNPILTUN PA-APA-A MOLIKPAQ MOLIKPAQ Japan PILTUN-ASTOKHSKAYA 2   PILTUN-ASTOKHSKAYA 10 SAKHALINSAKHALIN I I - - percent); and the Indian state-owned oil ARKUTUNARKUTUN PILTUN-ASTOKHSKAYA 4

 GOROMAYGOROMAY

BOATASINOBOATASINO SEV SEV

PA-APA-A MOLIKPAQ MOLIKPAQ ARKUTUN-DAGIARKUTUN-DAGI company ONGC Videsh Ltd. (20 percent). ARKUTUN-DAGIARKUTUN-DAGI ) PILTUN-ASTOKHSKAYA 15 CHAYVO-MORECHAYVO-MORE  PILTUN-ASTOKHSKAYA 3 YUZHNYYYUZHNYY VAL VAL

SREDNIYSREDNIY ASKASAY ASKASAY UST-EVAYUST-EVAY SAKHALINSAKHALIN III III Sakhalin-1 potential recoverable resour-

EVAYEVAY VOST VOST SAKHALISAKHALINSAKHALINI-NI- I -CHAYVO CHAYVO

SAKHALINSAKHALIN III III SAKHALINSAKHALIN I I - - EVAYEVAY NIZHNIY NIZHNIY ARKUTUNARKUTUN MIRZOYEVMIRZOYEV

DAGIDAGI NIZHNYEYE NIZHNYEYE DAGIDAGI VOST VOST ces are 2.3 billion barrels oil and 17.1 trilli- MONGIMONGI DAGIDAGI YUZH YUZH Southern Sakhalin Island VERKHNE-NYSHSKOYEVERKHNE-NYSHSKOYE DZHIMDANSKAYADZHIMDANSKAYA on cubic feet of gas (485 billion m3 of

TATAMSKOYETATAMSKOYE ZAP ZAP

Ilinskiy VERKHNE-TATAMSKOYEVERKHNE-TATAMSKOYE

LYSAYALYSAYA SOPKA SOPKA

VENINSKOYEVENINSKOYE VENINSKIYVENINSKIY IMCHINIMCHINIMCHIN UYGLEKUTYUYGLEKUTY I I gas). Sakhalin-1 will be one of the largest UYGLEKUTYUYGLEKUTY II II

KATANGLIKATANGLI ZAP ZAP KATANGLIKATANGLI

Tomari PRIBREZHNOYEPRIBREZHNOYE single foreign direct investments in Russia. Viakhtu KATANGLIKATANGLI SOUTHSOUTH

NABILNABIL KIRINSKOYEKIRINSKOYE The Project will be executed in phases. LUNSKOYELUNSKOYE Chekhov

SAKHALINSAKHALIN II II - - LUNSKILUNSKI Dolinsk LUNSKILUNSKI The initial phase develops the Chayvo field

UFSKOYEUFSKOYE KHOLMSKAYAKHOLMSKAYA License areas offs- with production start-up targeted for the

Kholmsk POLYARNINSKOYEPOLYARNINSKOYE hore Sakhalin as of

PIONERSKAYAPIONERSKAYA Yuzhno-Sakhalinsk Aleksandrovsk Sakhalinskiy fall of 2005. A dedicated oil pipeline and

Tymovskoye Due June 1, 2005. The terminal facility at DeKastri on the Russian Kirovskoye

LUGOVSKOYELUGOVSKOYE YUZH YUZH ZOLOTORHBNOYEZOLOTORHBNOYE LUGOVSKOYELUGOVSKOYE VOST VOST SAKHALINSAKHALIN II II LNG LNG recent discovery LUGOVSKOYELUGOVSKOYE VOST VOST ---PROPOSEDPROPOSED mainland will export crude oil to world Gornozavodsk POGRANICHNYYPOGRANICHNYY made by BP lies in markets beginning in 2006. The initial gas OKRUZHNOYEOKRUZHNOYE Sakhalin V and production will be sold in the Russian Far Onor PORANICHNYYPORANICHNYY TROUGHTROUGH represents a new East domestic market. Export of the remai-

Pervomaysk play which give fur- ning gas reserves via pipeline will com- Pobedino ther incentives to

Smirnykh Kenneth McKellar, Director Simon Crellin Matthew Snyder Mauro Andrade mence when a contract with a regional Petroleum Services Hill House, 1 Little New Street, 6 Shenton Way #32-00, DBS Building Tower Two 333 Clay Street, Suite 2300 Av. Presidente Wilson, 231- 8 andar London EC4A 3TR, UK Boshnyakovo Singapore 068809, Republic of Singapore Houston, TX 77002-4196, USA CEP: 20030-021, Rio de Janeiro, Brazil extend exploration Innovation in the global energy business Tel: +44 20 7007 0715 Tel: +65 6216 3286 Tel: +001 713 982 2378 Tel: +55 21 3981 0531 Fax: +44 20 7007 0167 Fax: +65 6538 6166 Fax: +001 713 427 4140 Fax: +55 21 3981 0600 Website: www.deloitte.com/petroleumservices E-Mail: [email protected] E-Mail: [email protected] E-Mail: [email protected] E-Mail: [email protected] away from Sakhalin. customer is secured. The Odoptu and Ark- utun Dagi fields will be developed as sub- sequent phases. The Chayvo field will be developed from in terms of a relatively simple petroleum racteristics with multidarcy permeabilities both offshore and onshore facilities. The system," says Vladimir Kudelkin. and porosities greater than 20 percent, Chayvo Yastreb land rig is designed to drill Kudelkin explains that there are two "says Kudelkin. In the South Sakhalin area extended reach wells to offshore targets principal source rocks, both of which are fractured Oligocene siliceous mudstones from land based locations. In June 2003, a Tertiary in age.It is the Palaeogene lacustri- are potential reservoirs. shore-based extended reach programme ne and shallow marine shelf with kerogen "In the Magadan and West Kamchatka (ERD) to install wells under the seabed at type II and III that give both oil and gas and areas distribution of potential reservoirs is distances exceeding 11 km to tap the the Miocene marine shales with kerogen little known but thick Palaeogene fluvial northwestern flank of the main Chayvo oil type II that give predominantly oil. The sandstones are probably the best potential zone was initiated. Six ERD wells have quantity of organic matter in the source reservoirs." been drilled to-date from Yastreb. rocks ranges from 0.6 to 4.2% and the Avariety of structural traps are present Oil and gas will also be produced from geothermal gradient varies between 2.4 to with Miocene-Pliocene wrench fault move- an offshore platform. The 20-well concrete 4.4 °C/100 metres."The Golden Zone" (GEO ments being most important. structure will serve as the offshore drilling ExPro no. 2, 2004), which supposedly con- "The small onshore fields occur within and living quarters and will be used to tains 90% of the hydrocarbons in a sedi- strongly faulted anticlines associated with develop the southwestern flank of the main mentary basin, should therefore be found Late Pliocene-Pleistocene inversion, says Chayvo zone. Installation of Orlan at Chay- approximately between 1500 and 5000 Kudelkin." vo is currently under way. The Orlan dril- metres below the surface. Theprincipal play model in the region is ling rig will be operated on the platform "The best reservoir rocks in the region hydrocarbons in reservoirs that are associ- year-round. The Chayvo Onshore Processing Facility are stacked deltaic sandstones deposited ated with the palaeo Amur delta system, will produce at the rate of approximately by the Neogene palaeo-Amur system since sealed by shales and sourced from the 250,000 barrels of oil per day and 800 mil- Early-Middle Miocene. Seismic data tells us Palaeogene. lion cubic feet per day. that the delta extended much further Exclusive agreement A 24-inch pipeline will be built from the north and east than Sakhalin in Eocene- Chayvo OPF to the DeKastri export termi- Early Oligocene times. Individual sandsto- "Our current understanding of the regi- nal on the Russian mainland. The pipeline ne beds vary in thickness from several tens onal geological setting in the Sea of construction started in 2004 and is sche- of metres up to more than 100 metres.The Okhotsk is based on evaluations and inter- duled to be completed at the end of 2005. sandstones have excellent reservoir cha- pretation of old seismic data with clear

38 GEO ExPro October 2005

EXPLORATION Courtesy of TGS

Seismic line north of Sakhalin Island shows high quality image and good definitions of local Tertiary basins above basement north of Sakhalin Island. The structural high in the middle of the section is the northern prolongation of the island itself. East of the high lies the Derugin basin. No wells have been drilled yetinthis area. The line is 250 km long.

limitations with respect to resolution and tains tilted fault-blocks, horsts, anticlinal vey, a third survey was acquired this sum- sequence definitions. Using modern, high structures and pinch out leads of world- mer. This is partly an infill to the existing quality seismic a new and better under- class sizes. "The presence of these ele- seismic grid, but also a test into Sakhalin 6 standing of the area can be obtained. This ments combined with a large number of to the southeast also to date suffering from will certainly benefit future exploration," Direct Hydrocarbon Indicators (DHI’s) give poor data quality. The geology in Sakhalin says Trommestad. reason for optimism in parts of Magadan 6isnot fully understood, but gravity and With this background TGS NOPEC in offshore areas," says Trommestad. magnetic indicate that huge basins could 1998 entered into a 5-year exclusive, rene- On the Khabarovsk shelf the 1998 sur- be present. wable agreement with DMNG. The purpo- veyconfirmed a heavily faulted structural "Another significant step forward has se was to make plans, acquire, process and trend where Tertiary deep grabens are been made with respect to data quality, market new non-exclusive seismic 2D-sur- thought to contain mature source rocks. and in combination with the extended veys in Eastern Russia, limited in the extre- More extensive acquisition is needed in coverage towards the deep-water areas of me northeast by the Bering Straight and by this area in order to establish confidence in the Sea of Okhotsk, this year’s survey will SeaofJapan in the southwest. The agree- leads and prospects. most likely image new structural elements ment thus encompasses the Bering Sea as and exploration models to be considered well as the Sea of Okhotsk. From now on New and more data in the future seismic programmes. More new modern seismic data would be availa- The agreement between TGS and DMNG data should therefore be acquired in the ble to the industry. has been extended with another five years, Khabarovsk, Magadan and West-Kamchat- The first programme under joint and during the summer of 2004 a non- ka areas," says Kjell Trommestad. TGS/DMNG operation (9700 km) was exclusive survey totalling 9,650 km (SA04) designed to confirm some of the major was acquired. The purpose was to get a Industry focus untested structural trends that DMNG had denser grid in Sakhalin 4 (northwest of There is an increasing interest for Sea of mapped around Sakhalin Island and on the Sakhalin) and Sakhalin 5 (northeast of Sak- Okhotsk among the international explora- Magadan and Khabarovsk shelves. halin), but also to test the idea of Tertiary tion companies. Several new players are fan deposition into a huge area east of the working with the multi-client data as a part Anewera for data Sakhalin, the Derugin Basin, in open areas of their initial evaluations, with the aim to Around Sakhalin Island the 1998 data not covered by seismic before. establish themselves as active investors represented a major improvement in reso- Based on review of preliminary data (fig. and partners in the region. However, key lution and definition of sequences and 3) from the SA04 survey, it is clear that the factors will be the availability of explorati- structural trends in many of the already objectives of the survey have been met. on licenses/acreage and that the processes established petroleum provinces. Pre-Terti- "The new data shows the presence of deep and terms related to this are predictable. ary sequences, specifically in Sakhalin 4 sedimentary basins not previously imaged. and 5 areas could now be defined, and un- These basins could represent a different drilled inversion structures in Sakhalin 1, 2 petroleum system than those we know and 3 stood out. about and have to be investigated further," This 1998 programme has confirmed says Trommestad. that Magadan geological province con- Based on the results from the 2004 sur-

40 GEO ExPro October 2005