Compared with vertical well, to improve the central degree of the casing is the key to solving the horizontal wells / large displacement well cementing quality. Increase the number of casing centralizer is the only way to improve the central degree of the casing, but increasing the number of casing centralizer will lead to difficult casing construction, solving the difficulty of casing operation and guarantee casing central degree improve at the same time is to use floating cementing technology.
Increase the number of centralizer will increase friction in casing process, the floating cementing reduce the borehole wall lateral force to overcome the friction resistance, which comes from increased number of centralizer.
Install flotation device in the casing structure, with closed casing air between casing shoe and float collar or low-density drilling fluids, have a buoyancy effect inside and outside the casing, so that it keeps the casing string in a floating state in the process, reducing friction between casing and borehole wall, which can install centralizer according to the designed requirements to ensure the casing central degree, and creating basic conditions to improve the well cementing quality.
-Rotary self-guided shoe
-High-strength float collar
-No-drill float arrangement
-Horizontal well centralizer
-Horizontal well plug
-Eccentric self- guide shoe: Flexible rotation, guide casing overcome obstacle;
-High strength dual valve Rotary collar: spring / tongue plate double spool, endure huge backpressure up to 50MPa.
-Drill-free float devices: use special blasting board material, pressure- crushed into small pieces, and be carried into the ground by mud easily.
-Horizontal wells centralizer: highly designed; rounded edge piece with small friction; free rotate decentralized small resistance, spiral edge chip high displacement efficiency;
-Does not change the traditional cementing technology, simple construction and operation.
From 2010 to 2013, in totally more than 350 oil fields horizontal wells were cemented. The casing went smoothly, cementing quality pass rate 100%, high quality rate 72.5%.