This paper describes successful implementation of degradable fiber-laden fluids for hydraulic fracturing in one of the largest oilfield in Western Siberia. Placement advantage of fiber-assisted fluid already becomes obvious after initial campaign of four fracturing treatments. It demonstrated good proppant carrying capabilities and allowed decrease of polymer load without increasing risk of premature screenout. Fibers proved to be reliable for successful placement of 10/14-mesh size Intermediate Strength Proppants (ISP) at concentration up to 1000 kgPA and higher with only 3.0 kg/m3 (25lb/1000gal) guar polymer loading, a feat previously only achievable with 3.6-4.2 kg/m3 (30-35lb/1000gal) gel loading in similar geological conditions.

In addition to reducing damage with lower polymer concentrations, other advantages of degradable fiber usage were anticipated to be proven after proppant fractures geometries and production parameters (including PI and Jd) evaluation. Analyses of the fracturing treatments have been performed based on bottomhole pressure gauges data and well-supported with direct fracture geometry estimation obtained by using differential cased hole sonic anisotropy measurements. As it is common for most formations in Western Siberia to have high degree of lamination and multiple shaly layers inside producing zone, pilot well-candidates for the project were specifically selected to have complex geology including several layers of sandstones and shaly strikes. This requires the fracture to intersect layers of sandstone and provide optimum connection for hydrocarbons flow to the wellbore, by evenly distributing proppant throughout the height of the fracture. Thus, degradable fiber-assisted fluid must be utilized, as conventional fracturing fluids may not suspend proppant for required time period and proppant settling during fracture closure results in considerable part of net pay being under stimulated.

The laboratory testing on large size ISP proppant suspension by degradable fiber in viscous fluids was performed for this project and described in the paper.

Western Siberia field and degradable fiber-laden fluid provided a good example of how one solution may be applied for various challenges of hydraulic fracturing optimization. This research will present a comprehensive story supported by technical analyses.

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