KHOLODILOV V.A., DZYUBLO A.D., KORYUKINA N.G., MANDEL K.A.
LLC "Gazflot" Russia

Ob and Tazov Bays of the Kara Sea are in Yamal, Gydanskaya and Nadym-Purskaya oil and gasbearing regions.

Ob and Tazov Bays area stock base analysis of raw material showed its high potential concerning gas content, however part of explored stock is not big yet. Significant part of hydrocarbon resources is concentrated in limiting shoaling water, that is why exploration work on the area of water are conducted very seldom because of operating complexities and high cost. But JSC "Gazprom" began seismic operations in Ob and Tazob Bays with the purpose to prepare water area structures for deep drilling, including exploration of shallow zones. Operator of work on the sea shelf is JSC "Gazprom" branch establishment LLC "Gazflot".

In 2001 JSC "Gazprom" with the purpose to clear up character joint of Kamennomysskoye-sea Cenomanian deposits conducted in shoaling water limiting zone marine seismic perations 2D do depth contours 4 in according to start-stop technology with application of 3 km bar in 320 miming km volume, hi season 2003 for the first time in Ob Bay area of water on Severo-Kamennomysskoye deposit seismic operations 3D in 600 km2 volume were performed.

Depth of sea on Severo-Kamennomysskoe deposit does not increase 12-15 m.

It is necessary to use great many self-floating means. While conducting exploration work it is necessary to use high-technology drilling and geophysical equipment adapted to conditions of given value. Wells drilling in Ob and Tazov Bays LLC "Gazflot" conducts from self-elevating drilling unit (JU) "Amazone" adapted to local natural-climatic conditions. JU "Amazone" function is drilling of exploratory wells for oil and gas with conditioned drilling depth up to 3000 m at sea depth from 4 up to 51 m. Field geophysical researches and tests in wells drilled in Ob and Tazov bays area of water in 2000-2003 were conducted with use of "Halliburton" firm equipment and test equipment providing reliability and quality of operations.

Operations region characteristics are complicated natural-climatic conditions. It is necessary to take into consideration natural factors influencing the process of exploration and fields arrangement -short iceless period (three months), permafrost soils, water level oscillations and others. Geological survey and hydrocarbon material production in bays water area are risk-bearing ecologically that is why it is necessary to assign means and carry out compensatory nature-conservative measures directed to conservation of ecosystems, hi order to ensure ecological security scientific and project institutes of Yamalo-Nenetsky A. D. Tyumen region (SibrybNIIproect TyumeiiNIIgiprogas, fishing control territorial bodies and OOC, protection of nature society departments, social ecological organization). LLC "Arcticecoshelf \ inter-departmental ichthyological commission and others were recruited.

Drilling operations are conducted at zero discharge. All the drilling waste -cuttings, hard domestic waste- are collected in containers and oil-containing water and oils are collected in tanks and utilized ashore. Drilling mud on the water base is used for drilling. Its conditioning is carried out by safe chemical reagents having maximum allowable concentration for water fishing basin.

LLC "Gazflot" reached definite results and experience in survey and exploration of hydrocarbon material fields in Ob and Tazov Bays area of water. Four fields are opened here-Kamennomysskoye - sea, Severo-Kamennomysskoye, Obskoye, Chugoriyakhinskoye with gas stock about 800 billion m³. This confirms new hydrocarbons deposits perspective of discovery in water area as well as proved oil-and gas presence in abutting dry land.

It is worth noted that subject developments are very near to Yamburg gaseous condensate development which is a very important factor providing advisability of exploration in Ob and Tazov Bays where infrastructure is developed and there is necessary complex for reprocessing and gas transportation to markets.

Thus in spite of complicated natural-climatic conditions in Ob and Tazov bays significant stocks of natural gas are discovered in Ob and Tazov bays water area and according to JSC "Gazprom" plan fields development will begin.

ARCTIC SHELF OIL AND GAS CONFERENCE 2004