Slotted in the oil casing or tubing in a variety of ways by cutting out some specifications on the longitudinal or spiral vertical cracks. Special slim cut and beams cut into the slit width (0.2-0.4) mm (according to customer's needs), and length is greater than 20mm (can be based on user needs). Sewing section as either rectangular or trapezoidal, and slot arrangement process according to user requirements. This product is good in sand and block, improve quality, mostly used in horizontal well and sidetracking and well branched. Foreign similar wells can reach over 90% slotted oil, is currently supporting dedicated pipe of special production process preferred.