Тампонажні розчини з диференційованим темпом набору міцності

Abstract

Based on the analyzing of industrial materials has been established that lot of gas wells characterized of inter-string flows and could not been effective be on stream. The article has been shown, that main base of this problem is poor quality well cementing, first off all the interval of reservoir horizon. After researched of information of well cementing has been ascertained that first eight hour of the curing of cement is attended by drop of the hydrostatic pressure. It becomes the main reason of oil and gas inflow. The drop of cement stone sealing properties during long time maintenance is result of poor cement stone resistance to thermocorrosion in the subsurface conditions. This is the reason that new cementing slurry recipe should be prepared. This recipes should be provides a differentiated rate of strength gain during the time of waiting the cement in conditions with high technological properties for long time maintenance. One of the most dangerous process during well construction is oil and gas inflow or inter-string flows in time of wait-on-cement time. This time is characterized special conditions of cement stone, because it represents as permeable matrix with hydration products, and with porous full by water. It is the best conditions for the flow of fluid throw pores. It can be the reason of suffusion channeling. In order to prevent for oil and gas inflow the article has been invited the achieve optimal distribution the pressure. For the realized this purpose can been used cementing process with two cement slurry batch with different setting up time. In practice of cementing of casing with length of section capital string, which shut off the gas more than 400 m, use differentiation the wait-on-cement time the portion of cementing slurry with length of cement column. In result start of time wait-on-cement in the bottom portion should be less for 2-3 hour than top portion.