CN2690557Y

CN2690557Y - Large diameter well drill bit

Info

Publication number: CN2690557Y
Application number: CN 200420010646
Authority: CN
Inventors: 翁行芳; 李俊波; 王爱芳; 李树盛; 李让; 赵顺英; 管林泽
Original assignee: Drilling Engineering Technology Research Institute Of Zhongyuan Petroleum Exploration Bureau Sinopec
Current assignee: Drilling Engineering Technology Research Institute Of Zhongyuan Petroleum Exploration Bureau Sinopec
Priority date: 2004-04-13
Filing date: 2004-04-13
Publication date: 2005-04-06
Anticipated expiration: 2014-04-13

Abstract

The utility model discloses a large diameter well drill bit, comprising a body, a drill column and a normal drill bit. Two ends of the body which is hollow are provided with screw threads, and the screw threads on the lower end is connected with the drill column. The lower end of the drill column is connected with the normal drill bit, and expanding bits composed of tooth claws, tooth wheels, bearings and teeth are equispaced on the same circumference of the body. The utility model drills into the stratum by simultaneously adopting the two drill bits, and a stepped well bottom is formed in the progress of drilling. The stepped well bottom changes the stressed states of rocks, and the rocks are relatively easily crushed. Therefore, drilling speed is improved, and a pilot bit is of small diameter, of broad selection range and of higher mechanical drilling speed; in addition, the tooth wheel structures of the expanding bits reduce the operational torque at the time of the drill bit expanding and improve safety factors.

Description

A kind of large hole drill bit

Technical field

The utility model relates to a kind of drill bit, belongs to drilling tool.

Background technology

The method of brill large hole commonly used is to adopt and the drill bit for the treatment of drilling well eye consistent size in the oil drilling, be lowered in the stratum, and circulating fluid, and rotary drilling-head creeps into.But because present large-sized bit model is single, series is incomplete, add mechanical energy and hydraulic energy deficiency in drilling process, cause the rate of penetration of large hole generally all lower, thereby drilling period is long, large hole well segment length in the drilling cost height, particularly deep-well, formation drillability is poor, and the problems referred to above are more outstanding.Counter-boring techniques commonly used comes the slim-hole that has been drilled to is carried out reaming both at home and abroad at present, and it has dual mode: a kind of is the diplocardia counter-boring techniques, generally adopts the diplocardia reaming bit to realize; Another kind is that the eye technology of reaming is again led in subdrilling, generally adopts hydraulic arm to stretch the formula reamer and realizes.The subject matter that the diplocardia drill bit exists at present is that operation torque is big, and the hole diameter amplification degree is little, and the reaming hole drilling speed is low, easily form the spirality well, and is simultaneously also high for large diameter its processing charges of diplocardia re-drill bit; The subject matter that hydraulic arm is stretched the formula reamer is that operation torque is big, simultaneously because of the existence of movable part is arranged, exists disconnected arm, blocks arm, arm contracts potential accident potential such as not returning original position.

Summary of the invention

The purpose of this utility model is exactly the shortcoming that overcomes prior art, and a kind of large hole drill bit is provided.It can be in drilling process bores neck eye and reaming simultaneously in same well, and gets out large scale well with the reaming bit consistent size with two drill bits under the situation of changing drilling tool that do not pull out of hole.

The purpose of this utility model is achieved in that the large hole drill bit is made up of body, drill string, conventional bit, body hollow, two ends are processed with screw thread, the lower end screw thread is connected with drill string, the drill string lower end is connected to conventional bit, is evenly equipped with the reaming bit of being made up of tooth pawl, gear wheel, bearing, tooth on the same circumference of body.

The utility model adopts two drill bits to creep into to the stratum simultaneously, in drilling process, form a step-like shaft bottom, the stairstepping shaft bottom has changed the stress state of rock, broken relatively easy, thereby can improve bit speed, and the pilot bit diameter is little, range of choice is wide, rate of penetration is than higher, and the operation torque the when cone structure of reaming bit has reduced the drill bit reaming has simultaneously improved safety factor.

Description of drawings

Fig. 1: large hole drill bit structure schematic diagram;

Fig. 2: A-A sectional view;

1-body, 2-tooth pawl, 3-gear wheel, 4-bearing, 5-tooth, 6-drill string, 7-conventional bit among the figure;

The specific embodiment

As shown in Figure 1, the large hole drill bit is made up of reaming bit and conventional bit 7 two parts, reaming bit is made of tooth pawl 2, gear wheel 3, bearing 4, tooth 5, reaming bit is distributed on the same circumference of body 1, body 1 hollow, the screw thread of having got on or off the bus couples together by screw thread and drill string 6, drill string 6 lower ends are connected to undersized conventional bit 7, i.e. pilot bit.

In the drilling process of large hole, at first a kind of large hole drill bit by being threaded in up and down in the drill string, at the bottom of the lower going-into-well, the pressurization of turn on pump circulating fluid is crept into then.Pilot bit 7 sizes are less, get out the well of a reduced size in front, and reaming bit reaming in the back gets out a larger-diameter well.Just form a step-like shaft bottom section like this in the down-hole, made the broken rock condition in shaft bottom obtain changing.The stairstepping shaft bottom is in tension and the stress state of being cut because the rock ambient stress obtains discharging under the effect of reaming bit teeth pressure, broken easily, efficiency of breaking rock obviously improves like this.The pressure that bears owing to the shaft bottom outer shroud reduces simultaneously, pilot bit 7 just can obtain enough mechanical rock breaking energy and hydraulic energy in energy distribution, the contradiction of mechanical rock breaking energy and hydraulic energy deficiency when having solved the disposable broken rock of large scale drill bit, solved also simultaneously that the large scale drill bit structure is single, model is few, form series, can not satisfy the on-the-spot contradiction of selecting drill bit according to the stratum, make full use of the wide advantage of minor diameter drill bit range of choice, help improving bit speed.In addition, a kind of fixedly concentric type structure of large hole drill bit can guarantee that the large hole hole diameter that finally gets out is regular, and wellbore quality is better.

Claims

1, a kind of large hole drill bit, it is characterized in that: it is made up of body (1), drill string (6), conventional bit (7), body (1) hollow, two ends are processed with screw thread, the lower end screw thread is connected with drill string (6), drill string (6) lower end is connected to conventional bit (7), is evenly equipped with the reaming bit of being made up of tooth pawl (2), gear wheel (3), bearing (4), tooth (5) on the same circumference of body (1).