Gas Wells Repair
Gas wells repair is an obligatory measure in well operation process, which can prevent wells both from shutdown and from severe irreversible colmatation of pore space in the well zone, which may lead to their reduction of their productivity. Gas wells repair is carried out in order to prevent emissions that can lead to even more clogging of the porous medium, and consequently, the subsequent reduction of the reservoir productivity. This leads to long restoration work, as well as significant costs for the construction of new wells.
The company SNK uses blocking hydrophobic emulsion solution СНК-2 (emulsion of reverse type having external hydrocarbon phase), not mixing with fresh and brine water, to enhance the effectiveness of gas wells repair and to improve reservoir properties before the main cycle of activities in order to provide temporary insulation (block) of the well.
СНК-2 solution is versatile enough to be effective when used in carbonate and clastic reservoirs, operated in a diverse range of conditions: a pressure of hydrostatic level, as well as in a range from abnormally low to abnormally high reservoir pressure. It is recommended for use the solution in a reservoir with temperatures up to 100°C, and the main damping fluid should have a density 2-3 grades lower than the density of СНК-2, the amount of еруinjected composition is recommended not to be less than 1 m3/m. This solution is successfully usedto kill all kinds of wells.
The particulate filler, which constitutesa part of the invert dispersions, contains elements of regular spherical shape, and substantially reduces the friction of the drill pipe on bore walls, that enables to block effectively the pore space. It is not abrasive.
When repairing gas wells, a recipeis designedindividually for each well, taking into account its lithology, current pore pressure, depth of permeable reservoir, and other factors.
Polysaccharide (biopolymer) liquids for washing and killing of wellsare presentedin the form of foam and gel based on modified guars. When combined with crosslinking agents, they form a uniform cross-linked structure, an effectively blocking the major cracks and small pores of rocks occurs.