During several decades high viscous guar-based gels remained main and single fluid type on Russian fracturing market. Having high viscosity and excellent proppant carrying capacity, crosslinked gel possesses damaging nature–it results in low retained conductivity of proppant pack even in case of oxidative destructors usage (<50%). In 2016-2017 low viscosity fluids based on synthetic polymer – polyacrylamide (High Viscosity Friction reducer, HiVis FR, HVFR, Viscous slickwater) started to be actively used in North America for shale fracturing. Along with improved sand carrying capacity in comparison with conventional FR due to its elastic properties, fluid demonstrated high retained conductivity of sand packs (~80%) confirmed during laboratory investigations, firstly performed by Stim-Lab (Stim-Lab Proppant Consortium 2015 – Fracturing Fluid Cleanup of various Low Polymer Fluid Systems; Stim-Lab Proppant Consortium - 2016 – Historical and current Friction Reducer Studies). However, fracturing design and job execution on conventional sandstones in Russia significantly differs from shales stimulations, i.e. serious work was required in order to start implementation of HiVis FR (Viscous slickwater) on sandstones in Russia. First field trials of Viscous slickwater were performed in Russia in the end of 2018 on conventional sandstones owned by "Gazpromneft-Khantos" - Gazpromneft subsidiary. In spring 2019 first time in the world full scale fracturing jobs, where Viscous slickwater with only ~30 cP at 511 s-1 demonstrated high transport efficiency to carry and place ceramic proppant at moderate rates (4-4.5 m3/min), as in combination with crosslinked gel as well as single fracturing fluid. Prior HiVis FR was qualified for application on sandstones as alternative to guar-based high viscous gels, major laboratory investigations were performed on novel fluid rheology, dynamic proppant transport, mechanical fluid properties, influence of breakers, etc (Loginov at al. 2019). Later, in field trials phase, additional laboratory testing was carried out to address specific fluid performance questions. New technology field trials for "Gazpromneft-Khantos" were executed with high operational success–according to initial fracturing design. Viscous slickwater was pumped as single fracturing fluid, as well in combination with crosslinked guar gels (≥50%). Jobs were performed on vertical, inclined and horizontal wells. Despitê20 fold difference in viscosity, high proppant transport efficiency of HiVis FR allowed to place standard for South part of Priobskoe oilfield designs in case of hybrids and slightly less aggressive designs in case of 100% jobs on slickwater. Application of Viscous slickwater allowed to identify number of advantages of novel fluid over traditional guar-based fluids both in terms of operational efficiency, location and environmental footprint and fluid performance characteristics. It was shown that start production of wells treated with slickwater were ~10-20% higher, and current production rate were comparable in comparison with traditional designs with higher proppant volume. Field trials on implementation of Viscous slickwater - fluids based on polyacrylamide on low viscosity reservoirs owned by "Gazpromneft Khantos" were proven to be successful both from operational and technological point of view and have become a new milestone in history of Russian fracturing. This basis could be key to the future effective development of analogical oilfields in the world.

No abstract

No abstract

The main purpose of jobs execution on the medium-permeability Parfenov horizon of the Chorskaya suite, its new site for research, was to confirm the effectiveness of the hydraulic fracturing to determine further ways to optimize and increase the economic feasibility of developing gas and gas condensate fields in the Eastern Siberia. The chosen strategy has made a tangible contribution to the successful realization of the project. This manuscript describes an integrated approach to performing hydraulic fracturing on a gas-bearing area in the Irkutsk region. The lithological features of the formation structure and the existing temperature and pressure conditions were taken into account. Numerous laboratory tests were carried out to optimize the fluid design before the hydraulic fracturing campaign, including the selection of a destructor system. To confirm the results of the final treatments, independent well tests were performed. The method of channel fracturing (pumping proppant with pulses) chosen for this project is currently successfully and widely used in Western Siberia and all the accumulated experience has been successfully adapted to the challenges of the unique formations of Eastern Siberia.

No abstract