New Opportunities for Brownfields: Channel Fracturing Offers a Significant Increase of Well Productivity in Complex Geological Conditions in the Samara Region

Abstract A characteristic feature of oil fields in the Samara region which main oil reserves are concentrated in terrigenous formations is considered to be a high level of exploration and depletion. One of the main challenges the solution of which will allow to maintain the current level of production is the systematic application of modern technologies for the oil inflow stimulation of small and hard-to-reach reservoirs with unfavorable geological and physical conditions. Under these circumstances the classical fracturing method with regular proppant injection has no the proper effect, what forces the oil producing companies to recourse to more efficient technologies. Gradually deteriorating geological conditions limit both the size of the proppant pumped and the tonnage of the whole hydraulic fracturing operation, not allowing to achieve the optimal "formation-well" connection. To optimize the fields development process in 2015-2016 four pilot operations were performed with a new technology for the region - the cluster fracturing. When it is performed, the proppant is being pumped with "pulses" alternating with self-dissolving fibers, thus achieving a highly conductive fracture structure that removes the restrictions for hydrocarbons inflow occurring during conventional fracturing. The development objects, treated with channel hydraulic fracturing, were sandstones of the Devonian system (D1, D3, Dk) of the Kuleshovskoye oil field, which was discovered as far back as 1959 and being the second largest in the Samara region. These formations are characterized by low reservoir properties and located at a much greater depth in comparison with the main oil reservoirs. The obtained results showed that the wells after the cluster fracturing demonstrated a productivity coefficient higher by 47%, the oil production rate increased by 1.56 times as compared to the wells with the conventional fracturing. Good production results were obtained due to the pad stage percent decreasing, a reduction of the fluid volume (when converted to the equivalent mass of standard fracturing), and the use of higher proppant concentrations.