SU1760068A1 - Well drilling tool - Google Patents

Abstract

Usage: well drilling core method with diamond crowns. SUMMARY OF THE INVENTION: The device includes a column tube and an adapter and a diamond crown attached thereto. The column tube is made of upper and lower parts interconnected by a flexible shaft with a crossbar, the free end of the shaft connected to the adapter, and the crossbar is connected to the lower part of the core pipe. Between the end surfaces of the lower and upper parts of the core tube there is a rolling unit, which provides the crown with torsional vibrations. This makes it possible to eliminate polishing of diamonds when drilling over low-abrasive rocks. 5 il.

Description

The invention relates to the mining industry, namely to devices for drilling geological exploration wells with core sampling in the exploration of deposits of solid minerals and water.

A device for drilling wells is known, which includes a column pipe and diamond rock cutting tools and an adapter attached to it (see Kornilov, NI, et al. Rock-breaking tools for exploration wells. M., Nedra, 1979, p. 244, fig. IV, 30, b).

The disadvantage of the above device is polishing of the diamond crown while drilling over low abrasive rocks. Polishing the crown leads to a decrease in drilling efficiency, premature termination of the voyage and extraction of the core set to the surface for sharpening the diamond crown.

The aim of the present invention is to eliminate the above drawbacks, namely, to increase its efficiency when drilling low-abrasive rocks by sharpening polished diamonds. This goal is achieved by the fact that a device for drilling wells, including a column pipe and diamond rock-breaking tools and an adapter attached to it, according to the invention, is provided with a rolling unit and a flexible shaft with a crossbar, and the column pipe is made of two parts interconnected by means of a flexible the shaft, the crossbar of which is rigidly connected to the lower part of the core tube, and the free end of the shaft to the adapter, the rolling assembly being placed between the end surfaces of the upper and lower parts core pipe.

The essence of the invention is as follows. In the process of drilling wells, the working end of the tool destroys the rock by micro-cutting, as drilling practice shows, in this case polishing of diamonds occurs, especially

Ltd

Especially when drilling non-abrasive rocks, which is caused by diffusion of the carbon atoms into the diamond, and the formation of a carbide layer on the diamond, the hardness is much higher than the hardness of the rocks in the massif,

Polishing diamonds reduces the efficiency of the drilling process and increases the cost of drilling.

The studies carried out with the help of high-speed filming, the operation of a diamond tool while drilling a special block of optical glass in their properties to rocks of category VIII-IX drillability showed that, depending on the parameters of the drilling mode, three modes of rotation of the diamond tool can be distinguished, which are characterized by addiction

soy

(%

1. Mode

2. Rotation mode with torsional vibrations (non-stop) - Ri22 (1):

we

3. Rotation mode with torsional ko: f (t):

uniform rotation R123 ();

lebani mi (with stops)

where odAUs is the dimensionless angular velocity of rotation;

(Ub is the angular velocity of the crown;

GW set the speed of rotation.

The invention is illustrated in FIG. 1-5.

On the basis of the obtained research results, a diagram of the stability regions of various modes of rotation of the diamond tool in the coordinates n – p (see Fig. 1) was constructed, where n is the projectile rotation frequency, rpm; P - axial load on the rock-breaking tool, daN.

The region of existence of the rotational mode Ri21 is characterized by a uniform rotation of the diamond tool around the axis of the well, without stopping and strikes. Ensuring the uniformity of rotation allows for increasing the mechanical speed of the drill at the same parameters. In this mode, the values of w and i are equal, therefore.

Ј ° b2

The region of the Ri2 rotation mode is very narrow and is characterized by high-frequency torsional vibrations, a decrease in the mechanical drilling rate and an increased wear of the rock formation matrix.

five

0

50

demolishing tool. In this mode, the angular speed of rotation of the tool is lower than the angular velocity specified by the machine's rotator. Some 5 braking of the tool rotation and its speed occurs, and this leads to the formation of vibration on the tool at the stop in this mode are absent, therefore

0

10ftfe.

The area of the Ri2 rotation mode is characterized by torsional vibrations with stops and blows of the tool against the face, increased tool wear and increases in the mechanical drilling rate. In this mode, shock loads are observed on the tool due to its stops at the bottom hole. The diamond tool stops are caused by the accumulation of the pressed

0 sludge under the end of the matrix and an increase - the braking moment. At the moment of stopping the tool, the angular velocity and angular velocity (Ik is equal to the set rotational speed. After stopping the diamond tool, the tool rotates with acceleration to a certain moment and stops again. In practice, the stopping time and the diamond tool turning time are approximately equal. Therefore, the ratio

00) 5 p

uJfc -uAn axial load and torque is transmitted to the tool during drilling. Under the action of axial load, the string of drill pipes loses stability and takes a wavy shape. At the moment of stopping the diamond tool, the constantly transmitted torque continues to twist the drill pipes. When this occurs, the length of the half-wave of the drill pipe decreases, and this leads to a reduction in the length of the string and to the separation of the tool from the bottom. When the tool is removed from the bottom, the force of the friction on the bottom is reduced and the tool gains acceleration due to the elastic properties of the drill pipes and the torque. This increases the half-wavelength of the drill pipe and the tool is in contact with the bottom of the well. Such blows against a face occur with a frequency of up to 200-400 Hz. Impact loads with high frequency expose new cutting surfaces on diamonds without changing their properties. Based on the results of research on the operation of diamond crowns in various modes of its rotation, the dependences of the abrasiveness coefficient of a rock-crown pair were obtained: (W) (see Fig. 2),

where Kd - the coefficient of abrasiveness;

W is the specific volume work of destruction.

Studies show that the coefficient of abrasivity Kd increases when the crown operates in the Ri2 mode. those. in the Ri23 mode, sharpening of diamonds occurs with the formation of new cutting surfaces (see, Fig. 3). This is confirmed by an increase in the mechanical drilling rate in the rotation mode of the diamond tool Ri2 (see Fig. 4).

Fig. 1 shows a diagram of the stability regions of different modes of rotation of the diamond tool; in fig. 2 shows the dependence of the abrasiveness coefficient of a rock-crown pair; FIG. 3 is a view of a blunted diamond grain in a crown matrix: in FIG. 4 the dependence of the mechanical drilling rate on the change in axial load; and in fig. 5 a device for drilling wells.

The device for drilling wells consists of an adapter 1 connected to a core pipe 2 made of the upper 3 and lower 4 parts, between which end surfaces a rolling unit 5 is placed and a flexible shaft 6 with a crossbar 7. Upper 3 and lower 4 parts of the core pipe interconnected by means of a flexible shaft 6, the crossbar 7 of which is rigidly connected to the lower part 4 of the core pipe 2, and the free end of the shaft 6 to the adapter 1, while the lower part 4 of the core pipe 2 is equipped with a diamond rock-breaking tool 8,

When setting the core-set on the face to the diamond rock-cutting tool 8 transmit torque, axial load and flushing R. daN

agent. During the drilling of a well, the working end of tool 8 by micro-cutting destroys the rock with the formation of a core column. The axial load is transmitted to the tool 8 through the rolling unit 5, and the torque is transmitted through the flexible shaft 6, the crossbar 7 of which is rigidly connected to the lower part 4 of the core pipe 2, and the free end of the shaft 6 to the adapter 1.

Transferring the torque to the diamond rock-cutting tool 8 through the flexible shaft 6 allows the crown 8 to be introduced into the rotation mode with torsional vibrations with a frequency of up to 200-400 Hz. Job

of a rock-breaking tool with torsional vibrations makes it possible to continuously form new cutting surfaces on diamonds when drilling into low-abrasive rocks and to destroy them in optimal

no diamond polishing mode.

Claims (1)

The invention The device for drilling wells, including a column pipe and diamond rock cutting tools and an adapter attached to it, characterized in that, in order to increase its efficiency in drilling low-abrasive rocks by grinding polished diamonds, the device is equipped with a rolling unit and a flexible shaft with a crossbar, and the core pipe is made of two parts interconnected by a flexible shaft, the crossbar of which is rigidly connected to the lower part of the core pipe, and the free end of the shaft placed between the end surfaces of the upper and lower parts of the core tube. BUT / 2 / U / / / R FIG. V fSfXtfttO border. ftof /, min / 000 J but Cm I 0