METHOD OF CEMENTING OF THE ADDITIONAL COLUMN OF PIPES IN THE INJECTION WELL Russian patent published in 2018 - IPC E21B33/14 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, in particular to repair of the injection well by descending an additional column of pipes and then cementing it. Method of cementing an additional column of pipes in the injection well includes the steps, on which geophysical surveys of the well are conducted to determine the state of the production string, the locations of disturbance intervals and perforation intervals, the assembly of an additional tubing string into the bore is lowered and installed, prepare the estimated volume of the oil well and pour it into an additional column of pipes, squeeze a grouting mortar from an additional column of pipes into the inter-column space of the well, leave the well for the time of waiting on cement – WOC. After carrying out geophysical studies, the intervals of violations and intervals of perforation with a blocking composition are sealed. At the mouth of the injection well, before assembling, an additional pipe string is assembled, a bottom-up shoe-type nipple with radial bores, a check valve, stop ring, shank of steel tubing, column of fiberglass pipes to the mouth of the injection well and a fitting made of steel tubing. An additional column of pipes is lowered into the injection well from the face to the mouth so that the shank of the steel tubing is positioned opposite the interval of perforation of the well. Then, the estimated volume of the plugging solution with a density of 1,430 kg/m³ is prepared at the wellhead, consisting of 84.45 % – oil-well portland cement-II-50, 15 % – foam glass, 0,5 % – fluid loss reducer, 0.05 % – defoamer. Further, in the additional column of pipes, the calculated volume of the oil-well slurry is pumped in and pushed through using a stopper with the process liquid density of 1,180 kg/m³ with a flow rate of 10–15 l/s, while in the process of squeezing the last 0.5 m³ a plugging solution, the process fluid consumption is reduced to 4 l/s. After the release of a grouting mortar from the intertubular space, but before the interaction of the stopper with the stop ring, fix the selling pressure. After that, the pressure in the additional column of pipes is reduced by 50–60 % of the value of the selling pressure and the well is left at the WOC. At the end of WOC, reduce the pressure in the additional column of pipes to atmospheric pressure and a secondary opening of the perforation intervals is made using a cumulative perforation. Then the flexible tubing string is lowered, the downhole is washed and the injectivity of the opened perforation intervals is determined, after which they put the well into operation.

EFFECT: proposed method allows to increase the quality of fastening of the additional pipe string, and also to increase the service life of the steel pipes of the additional column in the injection wells.

1 cl, 2 dwg, 1 ex