WELL ABANDONMENT METHOD Russian patent published in 2019 - IPC E21B33/13 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, in particular, to elimination of horizontal wells at ultraviscous oil deposits. Method involves determining intervals of casing string annulus leakage by geophysical methods, perforation with perforations of the casing string in the intervals of leakage. Well is removed after the process string is lowered in two stages, at the first stage the cement solution is being pushed in the intervals of leakage through the perforation holes, and at the second stage the well is filled with the cement solution to the well mouth. At that, in horizontal or inclined wells equipped with tail filters in interval of productive formation, before pack perforation packer-plug is installed, covering the filtering part of shank on the side of wellhead. Process string is equipped with a demountable packer before the lowering, at the first stage the cement solution is pumped to the lower perforation holes. Detachable packer is installed in middle part of lower leakage interval, into which design volume of cement solution is pumped through process string, which allows filling the whole leakage interval with injection pressure not exceeding allowable pressure for this well. Detachable packer after setting of the cement solution, but before its hardening, is removed and re-installed after the well is filled with cement solution to the next perforation holes. Consistently from bottom to top, all intervals of leakage are filled with cement mortar. After removing the detachable packer from the upper leakage interval, the second stage is started. For elimination of wells used for technological processes using thermal impact on the formation, it is necessary to use heat-resistant cement.

EFFECT: technical result is higher efficiency and reliability of horizontal well elimination due to reliable isolation of inter-layer behind-the-casing flows due to displacement of well fluid in casing string and filling of leakage intervals with cement mortar.

1 cl, 1 dwg