Konstantin Mikhailovich Lyapunov

First Steps of Channel Fracturing in Russia Set New Directions for Production Increase of the Oil Fields

Channel fracturing technique changes the concept of proppant fracture conductivity generation by enabling hydrocarbons to flow through open channels instead of the proppant pack. The new technique is based on four main components: proppant pulsing at surface with fracturing equipment and software, a special perforation strategy, fibrous material to deliver stable channels, and a set of models to optimize channels geometry. Channel fracturing in Russia’s oil fields began in 2008 as field testing operations in tight collaboration with the development team. Full-suite logs provided geomechanical models and ensured fracture channels optimization. An important result of those first treatments was long-term channels stability. The treated wells continue to show stable productivity over a fouryear period. As of today, more than 90 channel fracturing treatments have been pumped in Russia with no screen-outs. A very low screenout risk has become one of the most important advantages of the technology; the fibers make fluid more stable while the presence of clean pulses around proppant structures ensure bridging-free flow. As the channel’s conductivity does not depend on proppant size to hold channels open, treatments can be performed with smaller proppants (20/40 or 16/20 mesh) instead of larger proppants (12/18 mesh) that have an increased risk of screenout. In combination with abrasive jetting perforations, channel fracturing has proven to be an efficient stimulation solution for Russia’s multi-layered reservoirs. This completion technique ensures proper flow distribution into perforation clusters according to the channel’s specific requirements. It also allows reliable proppant admittance through jetted caverns. Channel fracturing increases the effective half-length with increased treatment size. A considerable number of channel fracturing jobs with proppant mass equal to standard fracturing designs have been performed—significantly increasing channeled length and providing better production in low permeability (1 to 3 mD) oil reservoirs. Based on production analysis of stimulated wells in five different areas, a correlation between incremental channel fracturing productivity over the conventional stimulation technique and kH value of the formation can be made: the higher the kH the more significant the advantage of the channel fracturing is in oil wells. Introduction Hydraulic fracturing in western Siberia is by far most effective method of oil production enhancement. Majority of the Neocomian formations have low permeability (1-3 mD) and high lamination in the fields around Nefteyugansk City. Priobskoe Field, one of the world’s largest conventional oil fields is a representative sample for the area. This giant field produces from three formations – AS12, AS11 and AS10, whose properties are shown in the Table 1. Many wells have simultaneous production from several intervals in which massive hydraulic fracturing treatments were placed since 2002 to maximize production. A history of the propped fracturing designs evolution was written by Timonov et al. 2006 and Nikitin et al. 2007. Priobskoe was always a primary target for new stimulation technologies, since it is relatively well-studied; fullsuite logs, core analysis, geomechanics studies and fracture geometry measurements are available for dozens of wells. Another feature of the formations is low water contents. Since this significantly lowers the risk of the fracture growing into a water zone, the optimum fracture design can be modeled without restrictions on the treatment size and proppant concentration. Several iterations in the optimization process were made with various new technologies that deliver longer