HEADING FOR THE TURONIAN GAS. New Gas Reservoirs are Being Developed in Russia

September 23, 2012

   Severneftegazprom has been hard pressed to turn around declining production at Yuzhno-Russkoye considering the gas field's importance as the source of throughput into the Nordstream Pipeline to Europe.

   But its first test well, which combines multi-directional drilling with dual completions technologies, foreign and domestic, has born first fruit in producing gas from shallow Turonian layers that until recently were ignored given their complexity.

   Severneftegazprom and Nord Stream invited Oil&Gas Eurasia in summer to the Yuzhno-Russkoye field to show the results of its work, and those of the contractors involved in the project including: Halliburton, TyumenNIIgiprogaz, Gazprom Bureniye, Korvet, and the plant GROM (Tyumen).

   Total reserves of the turonian gas of West Siberian fields amount to approximately 3 trillion cubic meters and the fields of this region provide the bulk of potential supplies for Russian gas exports to Europe (approximately 80 percent). As the Cenomanian reservoirs (from which most of Russia's gas is produced) gradually deplete, further exploration and development of the more shallow Turonian level reserves are becoming a top-priority in Russia. Turonian rock is softer than shale, thus easier to produce than shale. But it is harder than the source rock found in Cenomanian layers. Thus, it presents its own problems.

Beginner's Luck

   The project to produce gas from Turonian strata at Yuzhno-Russkoye field is currently in the “pilot” stage and is a first for Russia. Never before have Russian producers succeeded in tapping into these layers. There were several previous attempts to produce gas from Turonian reservoirs in Russia, but first experiments did not meet expectations. At Vyngapurovskoye and Lenskoye fields, Gazprom Dobycha Noyabrsk attempted to get to the Turonian zones using conventional vertical Cenomanian wells, which are traditional and optimal for the Cenomanian pools. But these were absolutely unsuitable for the Turonian because of the low production rates (approximately 10,000-18,000 cubic meters per day, which is significantly lower than the breakeven level in terms of ROI).
At that time, no one considered the option of either drilling directional and sub-horizontal wells (techniques which are now being used in the Yuzhno-Russkoye pilot project), or applying enhanced gas recovery technologies, so the projects on development of the gas fields were literally focused only on the Cenomanian. It was planned initially to exploit the upper zones and later switch over to the deeper ones. However, due to the demand for hydrocarbons, these plans were corrected as the production from the Cenomanian pools went into deeper decline.

   A key factor was that the Yuzhno-Russkoye field was selected as the mineral resource base for the Nord Stream gas pipeline, by which Russian gas is transported along the Baltic Sea bed to Germany and farther to Europe. Investors took an interest in the great volume of reserves of this unique field.
And in Russia's Far North, there appears to be a lot of Turonian gas. The volume of Turonian gas in the Yuzhno-Russkoye field exceeds 300 billion cubic meters. In the Kharampurskoye field to the south of