Research On Blocking Solution Against Gas-Migration And Cement Slurry In Qingshen Gas Field

All oil well cementing process face the problem cementing central channeling air, and it is a potential technical problem in cementing. Cementing central channeling air is one of the most difficultly technical challenges and it should be a considerable period of time to cementing the sector. Cementing after channeling has a bad effect on reservoir and productive, and sometimes it will lead to serious abandoned oil and gas wells and waste of resource.This paper discussed the central channeling air flow and the types of causes from the theory, expounded gas channeling process, discussed channeling potential factor, static gel strength, potential gas channeling coefficient (GFR), gas channeling factor (FGFP), gas migration index, cementitious local coefficient (GELFL), cement coefficient of performance evaluation of the anti-channeling system, introduced latex cement, fiber cement and a series of anti-cement slurry system. A new anti-channeling sealing liquid, blocking material+0.2%FS-800S+3%WD-830L+12%PS-l+3%JS- 210L +15%JR-800L+0.5%XP-800L+30%grit+5% silica power, is used sealing gas channeling, and optimization the sealing liquid formulation institute the effect of sealing liquid for gas channeling plugging. The results showed fluid sealing can seal cementing cracks for anti-gas channeling, so a new approach should be provided to improve the quality of cementing guarantee.This article aims to optimize the cement slurry system, G cement + 4.0%WD -830L+1.8%PS-l+3.5%JS-210L+0.3%FS-800S+15%JR-800L+0.5%XP-800L+35%grit +5% silica power+0.5%DZF-1+2%BXP-1, which is fit for the cementation for high temperature and pressure gas well avoiding the tendency towards gas migration. This cement slurry system has many advantages, such as anti-high temperature (180℃), right-angle colloid, against water/gas breakthrough and favorable rheological property. The article also evaluates the performance of cement slurry as a gas block, researches and analyzes the relationship among the microscopic composition of cement stone, the slurry system and the gas migration, and then found the cement slurry with fiber tenacity latexes is more effective, for its strengthening anti-shock ability of amulus interspaces. The performance of cement slurry as a gas block can be improved to a great extent. Thereby, the problems associated with high temperature and pressure cementation can be solved much better. It settles a base for cementing quality and provides a new way to avoid water/gas migration during cementation.