The dominant horizontal frac technique is the sectional frac technique with dual-retrievable packers in the Daqing Oilfield, which adopts the small diameter dual packers to stimulate the targeted formations one by one. For several intervals treatment can be done in one trip, reverse sand flushing and pulling the tubing upward fulfill the frac operation. The well-head equipments need to be assembled and disassembled repeatedly and pulling the tubing upward can lead to the low job efficiency, intense labors and high risk of well operation when fracturing multiple formations. The coiled tubings were introduced in the Daqing Oilfield, which were integrated with the sectional frac technique in the horizontal wells to take advantage of the coiled tubing and improve the frac efficiency. Five aspects were researched as follows: The redress kits of the coiled tubing were developed to match the dual-packers frac tools; Anti-blowing equipments on the well head were researched according to the whole length of the frac tools; The resistance of the coiled tubing and filmed proppants’ tests were researched to optimize the reasonable frac parameters; The assemble test between the coiled tubing and the conventional tubing widens the application of coiled tubing.
Up to now, the coiled tubing frac technique has been applied on 3 horizontal wells in the Daqing Oilfield, among which 5 intervals were fractured in Well A. The time of tubing pull upward saved more than 1 hour to improve the rig efficiency, reduce the worker’ s labor and lower the risk of well operation. The coiled tubing frac technique indicates a step up in the field of shallow horizontal well fracturing.