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

Acid multi-stage hydraulic fracturing involves metered injections of a special gelatinous compound and inhibited hydrochloric acid into the formation. During the first stage, a viscous layer fills the fractures in the reservoir. Subsequent acid processing makes it possible to accomplish deeper penetration of the compound into the formation. Treated channels remain open, which allows for the fractures 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 (1,970 ft.). A total of two hydraulic fracturing operations were performed in two separate production wells. After completion of the operations, the combined average flow rate of both wells will add up to approximately 80 tons of oil per day. The wells are functioning via natural flow.

“The method we’re using to raise oil recovery helps to 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 multi-stage hydraulic fracturing in new wells to enhance the development of the East area of Orenburg oil and gas condensate field,” says Gazprom Neft Orenburg CEO Alexei Ovechkin.

The East area of Orenburg oil and gas condensate field is a unique and one of the largest fields in the Orenburg region. Development of the field is complicated primarily by its geological characteristics, since fractured carbonate reservoirs with a high gas/oil ratio and hydrogen sulfide content predominate at the field.