This paper studies the principle and characteristics of bore trepanning processing technology of Nd-Fe-B permanent magnetic material by technological experiment,which develops proper and optimum processing technological parameters and establishes an empirical formula on the feeding force by multi-element regression analysis based on data of orthogonal test.

The work principle of a bore trepanning machine for rare-earth permanent magnetic material prestented.

FEM of sustainability for perforating casing with screw holding;

The greatest stress is on the aperture of the perforation casing.

In the process of oilfield production,perforation has much effects on casing mechanics performance,and serious damage of perforating casing in produced intervel is caused,thus cement hoop-casing perforation model is established and stress variation of perforation casing is analyzed.

The perforated casing is more vulnerable than common casing under external pressure.

The neglect of second and higher orders of small parameter ε will result in some errors when calculating the collapsing pressure of the perforated casing by using perturbation method.

The perforated casing is more vulnerable tocollapse under external pressure than that without per-forates.

Ideal open hole completion and casing perforation completion are derived from the update of the skin factor.