Progress of Polymer Gel Plugging Agent Formulation and Its Application in Ultra-Deep Horizontal Holes of Plateau Railway
The plateau railway crosses the southeast edge of Tibet,with complex and changeable regional lithology,and great difference in the strength and integrity of the rock bodies,which makes the line survey exceptionally difficult.In the directional drilling survey of ultra-deep horizontal hole,the significant hole leakage and falling blocks have seriously affected the drilling progress.Results show that the combination of large leakage channels,weak radial penetration of traditional plugging materials such as cement slurry,PAM+SZ803 polymer plugging agent,poor coagulation and the pumping effect when lifting and lowering the drilling,and other factors,all together led to complicated downhole phenomena such as block falling and jamming,collapsing and burying the drilling,loss of leakage,and bending of the drilling hole.In order to solve the problem of ultra-deep fracture leakage in horizontal holes,a new type of polymer gel plugging agent was synthesized by utilizing the mechanism of free cross-linking action of polymer gel.Through experiments to test the content of cross-linking agent,retarder(GH-8),carboxymethyl cellulose in the formula and the effect of temperature on the viscosity and time of gel formation,when poly(vinyl alcohol)was 3%,borax was 2%,carboxymethyl cellulose was 0.3%,GH-8 was 0.6%,and cross-linking temperature was 30～45℃,the time of gel formation was 74～91 min,and the viscosity of the gel formation of 247,400～25,440 mPa·s.These indexes meet the production requirements.Pressure sealing simulation experiments show that after adding 3%wood chips,the pressure capacity can be increased by 47%,and the leakage amount can be reduced by more than 30%.Production test shows that this gel plugging agent formula can effectively solve the problem of fissure leakage,with obvious wall protection effect,indicative of a good popularization and application prospect.
plateau railwayline surveyultra-deep horizontal holefissure leakagepolymer gel formulasplugging agent
国家科技期刊平台
NSTL
万方数据
