Full-sized diverting packer for large-scale multi-stage fracturing stimulation

After Daqing Oilfield entered its late development stage, peripheral Fuyang Formation having low permeability has become the primary target for oil production in Daqing Oilfield. Large-scale multi-stage fracturing techniques have been deployed to enhance productivity of individual wells to develop hardly reachable reserves. Currently, fracturing strings with staged slide-sleeve structures are used extensively in Daqing Oilfield. However the decrease of slide sleeves in diameter usually results in chocking energy loss around joints, potentially restricting discharging capacity. To eliminate energy loss related to pipe strings with reduced diameters, full-sized multi-stage diverting packers for fracturing stimulation have been developed, and by calculating chocking loss, proper diameters can be determined to achieve the maximum discharging capacity. ABAQUS finite-element software was applied to simulate and analyze contact stress among rubber barrel and casing to achieve desirable sealing performances. Laboratory oil immersion experiments confirmed the temperature resistance, pressure resistance and fatigue performances of these packers. By now they have been deployed in 4 wells, delivering a success rate of 100%. This indicates that the innovative full-sized fracturing technology is practicable for large-scale fracturing stimulation with high capacity and efficiency.