Study On High-Temperature Anti-Gas Cementing Technology

With the deepening of oil and gas exploration and development in China,especially in the north slope of the Western Tarim area,the depth of drilling is more than 7000 m,and the characteristics of high formation temperature and pressure have brought new technical challenges to cementing,especially in the high temperature and high pressure wells of ultra deep wells.On the basis of the research results at home and abroad,the advantages and disadvantages of the current evaluation methods of anti gas channeling performance of cement slurry are evaluated.According to the principle of mechanical balance,the mechanical analysis of cement slurry in three different stages of liquid,plastic and solid state is carried out and a new gas channeling condition formula is established.Using cement slurry pressure accurate transmission device to simulate the weightlessness experiment of cement slurry,the influencing factors of weightlessness law are analyzed,and the prediction model of cement slurry weightlessness is established.The strength decline law of cement stone and the change law of microstructure of cement stone under high temperature are studied,and the strength decline of cement stone under 200 centigrade high temperature environment is solved by reasonable proportion of coarse fine silica particle size compound.A high temperature anti gas channeling agent and admixture were selected,and an enhanced high temperature gas channeling prevention cement slurry system with high temperature resistant latex and nano liquid silicon was developed.The sealing performance of the cement sheath was evaluated by using the high pressure cement ring seal integrity test device.The cement slurry has been applied to the production of well cementing in well 1-7H well 177.8mm tailpipe.After cementing,the well logging results show that the unqualified well section is only 3%,and the cementing quality is a comprehensive evaluation.