HYDRO-PULSE PERFORATION OF OIL AND GAS WELLS WITH A POLYMER SOLUTION JET

Abstract

This paper analyzes the existing intensification method: hydro-abrasive jetting (or hydro-sandblasting perforation). Despite its effectiveness in establishing a reliable hydrodynamic connection between the formation and the wellbore, this method has significant drawbacks. Chief among these are the intense hydro-abrasive wear of pumping equipment and fittings, leading to a decline in the quality of perforation channels due to nozzle erosion, as well as the high resource and energy intensity of the process. As a promising and more advanced alternative, the authors propose the use of a high-velocity polymer solution jet (polyethylene oxide). The key innovative idea of the work is the application of a pulsed, rather than a steady (continuous), mode for delivering the water-polymer jet. The main hypothesis of the research posits that this approach, owing to the unique rheophysical properties of polymers, can significantly enhance the destructive capability of the jet. Theoretical justification and a series of experiments have fully confirmed this hypothesis. Studies of the behavior of polymer solutions under oscillatory flow conditions, which simulate the perforator's operation, revealed the existence of a critical pulsation frequency. It was established that maximum destructive efficiency is achieved when the pulse frequency corresponds to the maximum of the dissipative function. In this mode, the largest portion of the flow's energy is irreversibly dissipated and converted into destructive work. Experiments involving the perforation of a target model (steel, concrete, and rock formation) clearly demonstrated that the pulsed jet creates significantly deeper channels than a steady jet at identical initial pressures. Based on the results obtained, a conceptual solution and design for a new device–the hydro-pulse perforator–were developed. Its novelty lies in the use of a rotating rotor with V-shaped grooves, driven by an integrated hydraulic turbine. As it rotates, the rotor mechanically interrupts the flow of the working fluid to the nozzles, thereby generating powerful hydrodynamic pulses. An important design feature is the capability for axial displacement of the rotor, which allows for the precise adjustment of the pulse shape, duration, and frequency to achieve maximum destructive effect depending on the properties of the rock formation. Thus, the work demonstrates that the transition to a pulsed mode for water-polymer perforation is scientifically justified and highly effective. The proposed hydro-pulse perforator represents an innovative technical solution that meets the 'inventive step' criterion and paves the way for creating an energy-efficient and more productive technology for developing oil and gas formations.