Main producing horizons of the southern license block of the Priobskoe oil field are low-permeable sandstone formations AS10–AS12. Here, horizontal drilling and multistage stimulation (MSS) involving hydraulic fracturing have proved to be an effective way of field development. Full-scale testing of the channel fracturing technology has become the next stage of MSS optimization. This paper is dedicated to analyzing the efficiency of this method based on data from 40 wells.
Centered around creation of channels inside the fracture, the new method of hydraulic fracture allows better reliability of proppant placement without conductivity restraint; this is achieved by pulsing the proppant on surface, and use of fibers. Moreover, the channel fracturing technique provides significant savings in materials needed for a stimulation job – particularly, up to 45% of proppant and up to 20% of fluid – accelerating bringing-in of the as well as reducing the environmental footprint. The screenout risk is mitigated by pulsing the clean fluid and using fibers while using higher proppant concentrations at the same time.
Over the course of three years, more than 240 channel fracturing jobs were executed in 43 wells. This paper contains a detail analysis of performance of the wells put on production with implementation of the new MSS technique, compared to neighbor wells where conventional stimulation techniques were used. The wells are divided into groups, e.g. by fracture direction (transverse and longitudinal) and water content in the area, i.e. water-free sections and high water cut sections. The obtained production data proves that wells stimulated with channel fracturing show at least the same efficiency than wells where conventional fracturing was used, and involve better utilization of less resources.
The project described in this paper is the first experience of mass use of channel fracturing technique for horizontal wellbores in Russia. Lessons learnt from this experience, efficiency analysis, and applicability criteria defined in the scope of this project will help assess the potential of this new technique for other oil and gas fields in Russia.