Successful Restimulation of Western Siberian Oil Fields with Channel Fracturing Technique

Abstract

Western Siberia's Jurassic and Achimov formations are well known for low permeability, high heterogeneity, and lamination in which the majority of the wells require stimulation. However, production declines call for restimulation operations to improve field economics. Common challenges for both fracturing and refracturing treatments include achieving considerable effective half-length and increasing fracture conductivity while reducing screenout rates, which average 10%. To solve both problems, the channel fracturing technique was implemented.The 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.The use of the channel fracturing technique enabled economical production from 10 restimulated wells. Also, a reduction in screen outs was seen during refracturing treatments, which was an important advantage of the new method over the conventional stimulation technique based on homogeneous proppant placement.Bottomhole pressure gauges were used consistently throughout the campaign to study friction pressure and net pressure behavior during channel fracturing jobs. Overall, zero screen outs occurred throughout the campaign and well productivity was 15% to 30% higher when restimulated with channel fracturing.