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OJSC Severneftegazprom has patented its own method of developing multilayer gas fields with low-permeability reservoirs

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Invention relates to methods of gas production from boreholes, exposing several horizons of gas content.

Most often, the development of multilayer gas fields is carried out using separate grids of production wells for each development target, with the connection of wells operating different development targets to a single pipeline network. At the same time, field development begins with the production from lower gas deposits with a higher initial reservoir pressure, and overlying deposits are included in development when the current wellhead pressure of the wells draining the lower deposits decreases to the initial wellhead pressure of the wells draining the overlying deposits.

Gas reserves concentrated in the Turonian are hard-to-recover. The permeability of gas-saturated rocks is ten times lower than in the Cenomanian, therefore gas inflows are insignificant, and its development using traditional vertical and directional wells is impractical.

Improving the development efficiency of multilayer gas fields with low-permeability reservoirs is provided by drilling a directional well with U-shape design. The method differs from known analogs in that the well profile is preliminarily divided into six zones in accordance with the expected geological structure of the target layers (Fig. 1), while the profile is rotated starting from the top of the target reservoir with a deepening into it, but without reaching its lower stratigraphic boundary.

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Improving the efficiency of development of multilayer gas fields with low-permeability reservoirs is achieved by creating a well design consisting of a flat descending section and a steep ascending section, which allows the wellbore to be optimally positioned in productive deposits, which makes it possible to jointly operate several reservoirs with different properties, remove the fluid accumulated at the bottomhole and in the inflection zone, and also to increase the potential of the reservoir system due to their double opening.

OJSC Severneftegazprom is constantly looking for new technologies to improve production efficiency. The introduction of new innovative solutions in the development of hard-to-recover Turonian gas deposits has proven the prospects and efficiency of the innovative design solutions being developed.