The Development And Application Of Corollary Equipment In Casing Drilling

Casing drilling is a revolutionary technology in the field of drilling. Compared with conventional drilling, casing drilling could effictively reduce about 10% of drilling costs. However the key of this technology is the development and improvement of supporting equipment. In this paper, three kinds of supporting equipment were developed and applied in casing drilling technology.In this paper,the connections of casing and drill pipe were analysed and studied. Through casing collar surface, limit cam slip, hanging casing under the collar end were hold, it developed articulated casing holder which the instructure allowed its operating inclined angle 30°and the buckle of casing allowed its inclined angle 15°, so that the adapter sets a 20-fold expansion of the work angle.The holder could be avoided the damage of casing wall and the dropout of drill tools when the holder was hanged with failure, could be safely achieved quantitative indentation and self-locking function, and could be effectively transmitted driving force of the table to casing, so it meet the fast need among different threads. The special pipe thread of casing drilling was studied. Through the thread was appximated with the tooth angle and angle of taper, it could be achieved the same connections and disassembly with conventional drill pipe, and prevented the poor efficiency using others implements. Through the face of cylinder was sealed with external thread and the sphere was metal sealed with internal thread, it could be secured the relative displacement in seal adaptation and meet the need in the seal. Through the outside end face of external thread and the inside shoulder of internal thread were sticked together with the special angle, it could be avoided the buckle of casing continue process due to discontinuity load, so it had greatly improved the effct of sealing. The fixed drilling shoes of casing drilling was studied. The material of knife-wing was high-strength with carbide blade, and The material of knife in the wing is lower-strength with carbide blade built up welding. The carbide blade could be cut out bits. The bit was installed a sealed ball in the internal. The sealed ball and the ball seat were formed a single-flow valve to prevent drilling fluid into the bit ports when making a joint. The heart of drilling shoes is a drillability material. After the well finish and cementing, the heart of drilling shoes could be passed to the next bits and the rate of penetrate was correspond with the conventional drilling, After a well with surface casing and two wells with oil casing, field tests showed that: articulated casing holder, special casing thread and exclusive fixed drilling shoes met the design specifications and the application requirements...