Case studies and operation features of transient multiphase flow in low-flow wells with multistage fracturing and extended horizontal wellbore operated with ESP in PSA mode

The article is dedicated to the analysis and modeling of the operation modes of low-flow wells with extended horizontal wellbore (HW) and multi-stage hydraulic fracturing (MHF) during artificial lift with an electric submersible pump (ESP). A comprehensive analysis of the operation modes of Bazhenov formation wells with HW and MHF, working with ESP, has been conducted. Complications in the operation of ESP in such wells, related to proppant carryover, constant productivity decline, and gas factor growth, are shown, and operational data of various types of ESP in wells with complex construction are provided. One of the main parts of the manuscript is the new methodology for creating a model of multiphase transient flow in a well with ESP operating in periodic short-term activation (PSA) mode using specialized software. Various approaches for numerical modeling of transient multiphase flows in a well with ESP and a bottomhole separator were used to accurately describe the physical processes. Difficulties that may arise during well operation were demonstrated through the analysis of field data and numerical modeling results. The work includes modeling of complications in HW due to proppant carryover from MHF fractures, resulting in flow blockage in the well. The article demonstrates the process of tuning transient operation modes of a well with ESP in PSA mode using specialized software based on real field data (multiphase flowmeter, pressure gauges, etc.), taking into account the well construction, ESP characteristics, additional equipment (valves, separator, etc.), and reservoir parameters. The model was tuned to actual data, and possible ways of optimizing the operation mode were shown. In addition, the work provides an analysis of the sensitivity of fluid properties and well parameters to non-stationary flow in the well.