The Research Status of Bearing Seal of Cone Bit at Home and Abroad

Abstract

Cone bit drilling is the most important rock-breaking tool, its performance will directly affect the quality of drilling, drilling efficiency and drilling cost. High-speed roller bit bearing seal is the weakest link, but also wearing parts, is the most critical factor in determining the life of the high-speed roller bit. Field data statistical analysis showed that early damage caused by bearing failure drill 80% of the total failure of the drill bit, due to early failure and severe wear of the seal bearing 30% of the total failure of the bearing [1][2] . Sealing problem has become a serious impact speed cone bit drilling efficiency and drilling cost of technological bottlenecks, the current oil drilling project is urgently needed to solve the problem. Practice shows that current conventional cone bit bearing seal performance can not meet the requirements, especially in the high speed drilling, when lower seal life, sealing poor durability, seal wear, aging compared serious. Cone bits sealed condition very poor, including high temperature, high tempered medium, high load, and the size of a small sealed chamber, the working conditions and the environment will exacerbate the failure of the seal, but also to study the sealing tape to a lot of difficulties and challenges.Keywords: Cone bit; Seal problems; Research status Cone Bit Bearing Seal ProblemsSealing method currently used mainly rubber O-ring seal, floating seal bi-metal, a single metal floating seal, in recent years invented the double seal, but these are passive seal-tight manner, does not have the automatic discharge of sand functions in wells lower poor working conditions, severe seal failure, short seal life.(1) Rubber ring seal Rubber ring seal the biggest drawback is poor heat resistance properties and does not have exclusive sand, drill seal extremely harsh working conditions, including high temperature, high pressure, high tempered media, though, domestic and cross-sectional shape of the rubber ring to do a lot of research [3] -[5] , but the rubber ring wear property but it has not been solved. Especially at high temperatures, wear resistance of the rubber ring is even more serious, rubber brittle, hardened, abrasion resistance is greatly reduced, the seal will fail prematurely.(2) Metal floating seal Metal floating seal includes a bimetallic floating seal (Shown in figure 1.1) and a single metal floating seal (Shown in figure 1.2). Metal floating seal includes a primary seal and a secondary seal. Primary metal sealing surface of the sealing surface, the auxiliary seals are rubber O-ring seal. Metal floating seal the main problems: First, the primary sealing surface -metal contact surfaces can not be achieved after the deformation automatic wear compensation, once the particles into the mud, gradually increasing wear, the seal will lose its effective role, wear problems can not be resolved. Second auxiliary rubber ring seal -O remains of the rubber ring seal problem is the passive-tight manner, having no active discharge sands properties...