OREANDA-NEWS. A multiple hydraulic fracturing operation has been performed for the first time on a horizontal well drilled into carbonate reservoirs* in the East area of Orenburg oil and gas condensate field, operated by Gazprom Neft Orenburg, a subsidiary of Gazprom Neft. The operation was performed as part of Gazprom Neft's tight reserves program.

The drilling of horizontal wells using multiple hydraulic fracturing is the key technology for development of tight reserves. This technology makes it possible to complete several hydraulic fracturing operations on the borehole of an individual well in order to increase oil recovery by impacting individual strata one at a time.

Acid multiple hydraulic fracturing involves metered injections of a special gelatinous compound and inhibited hydrochloric acid into the stratum. During the first stage, a viscous layer fills the cracks in the reservoir. Subsequent acid processing makes it possible to accomplish deeper penetration of the compound into the stratum. The treated channels remain open, which allows for the cracks to have a high throughput and increases the influx of oil into the well.

Hydraulic fracturing in the East area of Orenburg oil and gas condensate field consisted of five stages. The length of the horizontal section reaches 600 meters. A total of two hydraulic fracturing operations were performed on two separate production wells. After completion of the operations, the combined average flow rate of both wells will add up to approximately eighty tons of oil per day. The wells are functioning via natural flow.

“The method we're using to raise oil recovery helps increase the flow rate of horizontal wells significantly by bringing larger quantities of reserves into development. The results we achieved clearly demonstrate that we can successfully apply acid multiple hydraulic fracturing at new wells to enhance the development of the East area of Orenburg oil and gas condensate field,” says Gazprom Neft Orenburg CEO Alexei Ovechkin.