Severe natural and climatic conditions, complex geology, and tectonic activity in eastern Siberia are just some of the challenges facing Russian companies in developing major gas reserves in the region.

Gazprom VNIIGAZ is tasked with developing the fields in the region. Problems include high helium and nitrogen content in the natural gas and bottomhole hydrate formation, said Pavel Tsybulsky, Gazprom VNIIGAZ, at the World Gas Conference 2012 in Kuala Lumpur, Malaysia, June 7.

The Chayadinskoye field in Krasnoyarsk Territory is a case in point. The license block covers 6,977 sq km (2,694 sq miles) and is scheduled for commissioning in 2016. Details of the project are in a paper written by Tsybulsky and D.V. Lyugai, Gazprom VNIIGAZ, on “Industrial development of Gazprom’s unique fields of eastern Siberia: Challenges and ways to address them.”

Key issues in developing the field include abnormally low reservoir pressure and temperature in the pay zones; low productivity of reservoirs leading to a high probability of hydrate formation at bottomholes and in well bores; the need for helium extraction and storage; lack of surface and subsurface water required for well drilling, completion, and production; instability caused by permafrost; poor infrastructure; and locating drilling pads in the boggy-rocky terrain, he continued.

The three producing formations – Biotubinsky, Khamakinsky, and Talakhsky – will be independently developed on a stage-by-stage basis. The commercially productive zones are at depths of around 2,000 m (6,600 ft). The Talakhsky and Khamakinsky sandstones contain gas condensate. The Biotubinsky sandstones contain oil and condensate.

Gas condensate deposits in the Talakhsky and Khamakinsky horizons will be developed first as a stage-by-stage pilot project for five years before commercial production begins, Tsybulsky explained.

image- drilling pads

Locating drilling pads in harsh terrain is one of the challenges in developing eastern Siberian fields

The field has abnormally low pressure (less than atmospheric pressure) and formation temperatures ranging from 9°C to 13.6°C (44°F to 54°F), which must be considered in the field development.

The Biotubinsky horizon has thin oil fringes with total oil in place of 200 million metric tons (1.5 Bbbl). The major part of the oil is in the gas-oil and water-oil contact zones.

Barrier technology is being developed to enhance the oil displacement from vertical wells. The first involves developing a nitrogen cushion above the oil fringe and the second is a polymer barrier between the gas cap and oil fringe. “In the initial phase of field development, three multifunctional wells for pilot-testing the barrier technology will be drilled,” he said. “It is recommended to develop the fringe using multifunctional wells with horizontal well bores with the barrier technologies.”

The technology developed in producing the Chayadinskoye field will pave the way for development of other eastern Siberian fields.