PDC drill bit capable of achieving casing drilling and design method thereof

[0044]In order to solve the problems existing in the traditional PDC drill bit when drilling into the cement section 2 in the casing, a design method for a PDC drill bit capable of casing drilling is specifically provided in this embodiment. The technical principle of the design method is: adopt 6 points The isolation method isolates the PDC drill bit from the casing 1 to prevent the cutting teeth 6 on the drill bit from cutting the casing during drilling. Take the 6-point isolation method as an example, such as Figure 5 As shown, the design method includes:

[0045] Install and arrange 6 isolation units 5 on the blade gauge part 4 of the PDC drill bit, and each isolation unit 5 is made of hard alloy. surface 8, and it can ensure that the continuation of drilling efficiency after drilling out of the casing 1 is not affected), but in actual application, it is not limited to only arranging six isolation units 5. It should be noted that: if the number of isolation units 5 If ther

[0057] In Embodiment 1, a design method of a PDC drill bit capable of casing drilling is provided, and a corresponding PDC drill bit is designed according to the design method provided. Drilling PDC bits such as image 3 , Figure 4 As shown, it includes a drill body 3, a plurality of blades evenly distributed on the drill body 3 along the same circumferential direction, and each blade is divided into a gage part and a cutting tooth part 6, and the PDC drill bit also includes:

[0058] Two isolation unit groups, each isolation unit group is provided with 3 isolation units 5 (there are 6 isolation units 5 in total in the two isolation unit groups), each isolation unit 5 is made of hard alloy, and the same isolation unit Each isolation unit 5 of the group is respectively arranged on the gage part of each described blade and is surrounded by each isolation unit 5 of this isolation unit group to form a virtual plane 7; In the present embodiment, each isolation unit group respectivel