Improvement and Application of Key Tools for Hydraulic Jet Fracturing

Daqing Oilfield Production Engineering Research Institute, Daqing 163453, China

^* Corresponding author: yibozhang@petrochina.com.cn

Abstract

Aiming at the problems of poor reliability, low construction efficiency, and short service life of fracturing string in the application of hydraulic jet technology in Daqing Oilfield, targeted research has been carried out on key tools such as rubber cylinder, slip, and nozzle.A unidirectionally-sealing rubber cylinder adopting composite sealing method was designed. The rubber cylinder could bear the pressure of 80 MPa and temperature resistance of 150^∘C under the setting force of 20 kN, with tensile strength increased by 23% and residual deformation rate less than 3%, showing good overall sealing performance and recovery. The finite element method was used to optimize the structural parameters, materials and process of the slip to increase the ability of slips to withstand alternating loads by 1.5 times. The arc-shaped nozzle was improved to reduce the pressure drop and increase the jet density. By improving the performance indicators of key tools, the optimized fracturing string could meet the construction requirements of low setting force, high sealing pressure difference, and repeated setting and fracturing. The improved technical string was applied to section 3459 of well 218 well in the field, with the success rate reaching 100%. The large-scale application of the improved fracturing string satisfied the construction requirements for large-scale volume fracturing of the for the 5 1/2" inch casing new well completion in the low-permeability and tight reservoirs of Daqing Oilfield.