METHOD FOR OPERATING INJECTOR WITH MULTIPLE PACKER ASSEMBLY Russian patent published in 2015 - IPC E21B43/14 E21B33/122 

FIELD: oil and gas industry.

SUBSTANCE: method includes running in of the assembly to the well, setting packers and their leak testing, dual injection of working fluid to productive formations. Before running in the production string is gauged by a gage with length from 30 up to 100 m and diameter less than diameter of the production string per 4-6 mm, at that intervals of gage setting and tightening are marked and reasons for tightening are defined. The production string is studied within intervals of packer setting and intervals of the gages setting and tightening. The well is washed by back washing until clean flush fluid is obtained. The assembly is being assembled. Axial packer is used as the lower packer and thrust plate packers are used as the upper packers. A cable is connected to devices and fixed at outer surface of the assembly. The assembly is run in and its hydraulic leak testing is performed. The plug is removed by means of wire-line technique. The assembly is run in to the well to the required depth at tubing string with measuring length and gaging of inner cross-section of the tubing string. Simultaneously the cable is fixed at outer surface and the cable is run in together with the tubing string. Running speed should be maintained at 0.1 m/s at most. The cable tension is controlled during its running in; no jerks and tension release are permitted. When the tubing string is set to power slips the cable should not be trapped by slips, when releasing the tubing string out of power slips pulling depth should be less than 0.25 m. During running-in weight unload of the tubing string should not be more than 2 t and at unplanned setting of the packer in transport position the tubing string is lifted per 2-3 m and the tubing string is run out slowly passing the packer through interval of unplanned setting. The packers are positioned, fitting of the assembly is made to the preset interval by adjustable tubes, the cable is spliced with wellhead devices, chuck and preventer is mounted, hydraulic leak testing is performed for the tubing string. Value of the tubing string lifting with assembly for packers setting is calculated, the required length is determined for cables from the wellhead up to the controller panel, cable excess is cut, cables are bypassed through the cable input, the packers are set by fixating changes in weight of the tubing string, glands of the cable input are sealed off and functional check of the devices is made. The packers are pressed together and set to gas lift mandrels of pressure regulators with unions of the preset diameters or bottomhole pressure gages, at that during operation at working fluid pumping pressure is measured in the tubing string and annular space between formations and opposite each formation. Dependence of pressure in annular space is controlled on changes in injection pressure of the tubing string; overflow availability is monitored from under the packer to behind-the packer space. Fluid flow rate is defined between packers opposite the formations and when pressure occurs in annular space notwithstanding changes in injection pressure then pressure is released through the casing valve.

EFFECT: improved efficiency of multiple packer assembly setting in the well.

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