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After hydraulic fracturing treatment, wellbore clean-out takes significant amount of time, and therefore, the commissioning of the well is delayed. In addition to production losses, production companies CAPEX and OPEX are also increasing proportionally to frac fleet activity. As a common practice, in western Siberia fracturing treatment is underflushed by about 0.5 cubic meters. This is supposed to prevent unintentional overflush and, as a result, hydraulic fracture closure at the wellbore. The loss of contact between the propped fracture and the perforated section of the well can neutralize the effect of hydraulic fracturing. This can happen in the first days of production after the operation or in a long-term perspective. On the other hand, overflush during hydraulic fracturing is common practice for unconventional formations. It allows to use various well completion technologies with the cemented liners and significantly reduces time required to complete multistage fracturing treatment. The objective of this paper is to show the approach and experience of the company "Salym petroleum development" (SPD). Positive result was obtained with proppant slurry overflush operation during treatment of conventional reservoirs.

Modeling the correct fracture geometry in hydraulic fracturing simulators is challenging. Mapping the fracture can reduce the degree of uncertainty and help adjust the hydraulic fracturing model in the simulator. To map fracture height, acoustic or temperature logging can be used, as well as pulsed-neutron logging combined with tagged nonradioactive tracer (NRT) neutron-absorbing proppant. This article compares the data for modeling a hydraulic fracture in pseudo three-dimensional (P3D) and full 3D (F3D) hydraulic fracturing simulators with the results of studies of mapping fracture height in a well. Analysis of well survey data allowed assessment of the degree of fracture penetration from an oil reservoir through a clay barrier in an aquifer. Interpretation of cross-dipole acoustic logging, which characterizes impaired continuity of the medium, coincides with the interpretation of dual-burst thermal-decay time log (DBTDT) data, reflecting NRT proppant placement in hydraulic fractures near the wellbore. Bottomhole pressure analysis and comparison of production before and after hydraulic fracturing also confirm fracture height measured using two methods: F3D and P3D modeling. The experiment showed that F3D modeling more accurately calculates fracture height than P3D modeling. The interpretation of temperature logging does not correspond to the fracture model and is not supported by other logging methods; therefore, this type of logging cannot be used to adjust fracturing design models.

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