The major volume (62 %) of the current recoverable reserves at the RN-Uvatneftegas fields is confined to the Tyumen formation, while a significant portion is concentrated in areas with poor reservoir properties. Thus, at the Severo-Tyamkinskoye field, when developing oil reservoirs with permeability of less than 2·10-3 μm2 by directional wells with hydraulic fracturing, low startup rates and high decline rates were observed, as well as lack of any effect from applying a waterflooding system with directional wells used as injectors. Horizontal well patterns in combination with multi-stage hydraulic fracturing are an economic technology for the development of hard-to-recover reserves. The feasibility of drilling horizontal wells with multistage hydraulic fracturing in low-permeable reservoirs at the fields of RN-Uvatneftegas has been confirmed by pilot projects and results of a detailed sector flow simulation model runs (over 300 feasibility runs) which reproduced the typical properties of low-permeable reservoirs of the Tyumen formation. The flow simulation model runs and the pilot operations are used to roll out the HW systems with multistage hydraulic fracturing within the Tyumen formation reservoirs. As of January 1, 2020, 53 horizontal well with multi-stage hydraulic fracturing were drilled in the Tyumen formation reservoirs (J2, J3, J14, J24) at the fields of RN-Uvatneftegas with permeability ranging from 0.2·10-3 to 2·10-3 μm2. The actual well operation confirmed the theoretical conclusions: the average startup parameters of horizontal wells are more than twice as high, while horizontal wells are, on average, started up at lower drawdowns. The decline rates of horizontal and directional wells are comparable, an increase in the length of a horizontal section and the number of frac jobs leads to an increase in the startup rates and overall productivity of horizontal wells. With comparable decline rates and high start-up oil rates, the expected oil production from horizontal wells significantly exceeds that of directional wells.
References
1. Chusovitin A.A., Gnilitskiy R.A., Smirnov D.S. et al., Evolution of engineering solutions on the development of Tyumen suite oil reserves on an example of Krasnoleninskoye oilfield (In Russ.), Neftyanoe khozyaystvo = Oil Industry, 2016, no. 5, pp. 54–58.
2. Patrakov D.P., Plitkina Yu.A., Glebov A.S., Development experience of low permeable reservoirs of Tyumen suite of Krasnoleninskoye field RN-Nyaganneftegas JSC (In Russ.), Neftyanaya provintsiya, 2019, no. 2, pp. 72–100.
3. Ovcharov V.V., Ovcharova L.P., Updating number of frac stages for horizontal wells producing from low-permeability reservoir in Vikulov formation on Kamenny license block (In Russ.), Neftyanaya provintsiya, 2020, no. 2(22), pp. 59–72.
