At present, the competition of oil industry is very fury, so reducing the cost of exploitation of oil is imperative under the situation. but the oil drillers of our country are relatively old, and the control mode drops behind, which result in the long period of making hole and high ratio of aiguille attaint, which is the main restrict factor of reducing the cost of oil exploitation
Air hole grate
Planting bar used syringes from the bottom of the hole to put adequate amounts of external uniform adhesive filling injection hole, pay attention not to air hole inclose
Supermassive black hole in andromeda galaxy
The plate was loaded in its own plane by a pin passing through the hole in an annular disc fitted in the hole in the plate.