JPH047277Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] The present invention is a continuous bottomhole data telemetry system used as a means of transmitting information about the well or strata from the bottom of the well being excavated to the ground. The invention relates to a pulse generator for a switching system.

[Prior art]

Continuous bottomhole data telemetry system
It has recently been in the spotlight as another name, Measuring While Drilling (hereinafter abbreviated as MWD), and has been put into practical use in the field of oil exploration in the United States for several years. From there, various information about the well or geological formation, such as the direction and angle of inclination of the tip of the drill pipe during excavation work, and the temperature and pressure of the bottom of the well, is transmitted to the ground.

The mainstream of MWD technology development is the mated pulse method, which has already entered the stage of practical use by several companies.The pulse-up method and pulse-down method are typical examples of this method. This is compared to the conventional method of obtaining the above information by suspending the detector from the tip of a wire and lowering it to the bottom of the well after all drill pipes etc. are pulled up from the well while drilling an oil well. It will be increasingly put into practical use in the future as a measurement means that can reduce the work required to pull up drill pipes, etc., and improve the efficiency of excavation work.

Therefore, of the above two methods, the pulse-down method has a smaller valve in the pressure signal generating section than the pulse-up method, requiring less driving force, and has a higher repetition rate of valve opening and closing, so the data transmission rate is lower. It has the advantage of being expensive.

Next, the principle of the pulse-down type pulse generator of the conventional MWD will be explained with reference to FIG. Drill pipe 2 is attached to the lower end of casing 4 inserted inside.
An instrument section 5 is provided which has a built-in sensor to obtain information such as the direction of the inclination, the inclination angle, and the temperature and pressure of the bottom of the hole, and the information obtained by the instrument section 5 is transmitted to the ground as a pulse signal. , is calculated by a computer.

Therefore, in this pulse-down type pulse generator, a part of the high-pressure muddy water Mh pumped from the ground is pumped to the inner periphery of the bedrock 1 and the drill pipe in order to assist the drilling by the bit 3 and to transport the excavated debris to the ground. 2
A mud water bypass passage 7 is provided that bypasses the mud water M in the low-pressure part of the mine 6, and a piston valve 9 that is operated up and down by a solenoid 8 is provided in the middle of the mud water bypass passage 7. By opening and closing the muddy water bypass passage, the pressure of the high-pressure muddy water Mh drops rapidly, and the pressure difference generated at this time becomes a pulse down pressure and serves as a signal mechanism that is transmitted upward.

Figure 8 shows the relationship between the pressure of the muddy water Mh and time at that time, and the generated pulse is indicated by P, and the signal is modulated by changing the pulse interval.

The conventional pulse down method explained above
In the MWD pulse generator, solenoid 8
muddy water bypass passage 7 by the piston valve 9 and
Since the piston valve 9 is opened and closed, the piston valve 9 is controlled by turning on and off the current to the solenoid 8, and the force applied to the drive unit due to the pressure difference between the wedge-shaped opening and closing is reduced. is large,
There is a problem that driving power becomes large.

The characteristics that this type of pulse generator should have are a small driving force for pulse generation, a large amount of information to be transmitted, and excellent reliability. Conventional pulse oscillators do not completely satisfy these characteristics, and improvements in these characteristics are desired.

[Purpose of invention]

The present invention solves the above-mentioned conventional problems, requires less driving force for pulse generation, increases the amount of information transmitted, and has excellent reliability.
The purpose is to provide a pulse generator for MWD.

[Structure of the idea]

To achieve the above object, the pulse generator of the continuous bottomhole data telemetry system according to the present invention inserts the casing up to the tip of the drill pipe and supplies high-pressure muddy water to the space between the drill pipe and the casing. A passageway is formed in the casing, an inflow passageway for muddy water is opened in the casing, and a spouting passageway for spouting the muddy water that has flowed into the casing out of the drill pipe near the bit is opened, and the inflow passageway is opened in the casing. A rotary stopper is provided at the connection part between the and the spout passage, and this rotary stopper has a communication hole that can be connected to the inflow passage, and a spout hole that has one end connected to the communication hole and the other end connected to the spout passage. The rotary plug is configured to be driven by a driving means housed in the casing so that the communication hole is intermittently communicated with the inflow passage to jet high-pressure muddy water out of the drill pipe.

That is, the structure is such that a part of the muddy water flowing through the high-pressure muddy water passage between the drill pipe and the casing inserted therein flows into the casing, bypasses the muddy water to the side of the drill pipe, and blows out. A rotary stopper driven by a driving means such as a DC servo motor is provided in the bypass passage, and the bypass passage is intermittently opened and closed as the rotary stopper rotates. The rotary stopper has a T-shaped communication hole and an ejection hole so that the inlet passage and the communication passage are intermittently communicated with each other as the rotary stopper rotates.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a cross-sectional view of the main parts of the MWD pulse generator according to the embodiment of the present invention, and has a structure that is almost the same as the conventional example shown in Figure 7, with the same parts and part numbers as in Figure 7. It shows.

A flow path 2a for high-pressure muddy water Mh is formed between the drill pipe 2 and the casing 4 inserted therein, and furthermore, near the tip of this casing 4, a part of the muddy water Mh is channeled into the casing 4. A bypass passage 7 is provided, which includes an inflow passage 7a for introducing the muddy water Mh into the casing, and an ejection passage 7b for spouting the muddy water Mh out of the casing again. A rotary plug 10 is rotatably provided at a connecting portion 7c between the inlet passage 7a and the ejection passage 7b by a driving means such as a DC servo motor 11.

As shown in FIG. 2-A, FIG. 2-B, and FIG. 2-C, the rotary plug 10 passes through the main body 10a in the lateral direction and has a communication hole 12a and an ejection hole 12b perpendicular to the communication hole 12a. A T-shaped communication hole 12 is provided, and when the rotary stopper 10 is driven by the DC servo motor 11, the communication hole 12a connects to the inflow path 7a as shown in FIG. 3-A. Spout channel 7
The bypass passage 7 formed by b is connected to the underground mine 6.
By repeating the open state in which the muddy water Mh is spouted out and the state in which the bypass passage 7 is closed as shown in Figure 3-B, the high-pressure muddy water Mh in the passage 2a is intermittently supplied to the underground mine 6 via the bypass passage 7. It is made to eject at a specific time to generate down pulse pressure.

As a result, the information obtained by the instrument section 5 is transmitted to the ground as a pulse signal using down pulse pressure, and the computer calculates the relationship between the pressure of the high pressure muddy water Mh and time. FIG. 4 shows this, and the generated pulse is indicated by P.

In the pulse generator of the present invention, the signal is modulated by changing the frequency of the pulse P, and as a result, the amount of information transmitted can be increased.

On the other hand, by controlling the rotary plug to open and close, it is also possible to select a method that changes the pulse interval as shown in FIG. 8, which is similar to the wedge-shaped opening and closing.

Further, in the pulse generator of the present invention, the DC servo motor 11 is used to open and close the muddy water bypass passage 7.
Since the rotary stopper 10 rotated by a drive device such as the above is provided, the force applied to the driving part of the rotary stopper 10 is smaller than that in the conventional example shown in FIG. The driving force can be reduced, and the rotary plug 10 system has fewer failures and is more reliable than the piston valve 9.

The pulse generator of this invention has the ability to operate reliably at a depth of several thousand meters underground.
Servo motor 11 (rotary solenoid may also be used)
may be stored in the pressure chamber 14. In this case, the transmission of the rotational torque to the rotary plug 10 takes place by means of a magnetic coupling 15 . Further, in addition to the magnetic coupling 15, a deceleration means 16 is provided between the DC servo motor 11 and the rotary plug 10, thereby increasing the transmitted torque and imparting a predetermined rotational speed to the rotary plug 10. When the deceleration means 16 is arranged inside the pressure chamber 14 (see FIG. 6)
There are two cases: and the case where it is arranged between the magnetic coupling 15 and the rotary stopper 10 (see FIG. 5).

[Effect of idea]

The pulse generator of the continuous bottomhole data telemetry system according to the present invention inserts the casing up to the tip of the drill pipe to form a passage for high-pressure mud water in the space between the drill pipe and the casing. an inflow passage for muddy water that opens into the passage, and a spout passage for spouting the muddy water that has flowed into the casing out of the drill pipe near the pit, and a connecting portion between the inflow passage and the spout passage. A rotary plug is provided in the rotary plug, and the rotary plug has a communication hole that can be connected to the inflow channel, and a spout hole that has one end connected to the communication hole and the other end that is connected to the spout path. The communicating hole is driven by a driving means housed in the casing to intermittently communicate with the inflow path to jet high-pressure muddy water out of the drill pipe.

In particular, in the present invention, a bypass passage is formed in the high-pressure muddy water passage, and a rotary stopper is provided in the middle of this bypass passage, and this is rotated by a driving means to allow the high-pressure muddy water to pass through the bypass passage intermittently. When the bypass passage is closed, the high-pressure muddy water on the left and right sides acts on the rotary plugs to maintain pressure balance, and when the bypass passage is open, the T-shaped The muddy water that flows in from the horizontal communication holes joins and flows out to the spout hole, so the pressure balance can be maintained. Therefore,
The force needed to rotate this rotary stopper is small, and it can be operated accurately and without failure. Furthermore, since the signal is modulated by changing the frequency of the pulse, the amount of information transmitted can be increased, and the pulse generator of the present invention has the advantage of improving its reliability.

Note that the present invention can be effectively applied mainly as a pulse oscillator for MWD using a down-pulse method.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a main part of a pulse generator of an MWD according to an embodiment of the present invention, Fig. 2-A is an enlarged side sectional view of the rotary stopper shown in Fig. 1, and Fig. 2-B is a sectional view of a main part of a pulse generator of an MWD according to an embodiment of the present invention. A- in the diagram
Front view in direction A, Figure 2-C is B- in Figure 2-A
The plan view in direction B, Figures 3-A and 3-B are plane sectional views of main parts showing the open and closed states of the muddy water bypass passage in Figure 1, and Figure 3-A shows the open state, and −
Figure B shows the closed state, Figure 4 is a pulse diagram showing the relationship between the pressure of muddy water and time by the pulse transmitter of Figure 1, and Figures 5 and 6 are other embodiments of the present invention. FIG. FIG. 7 is a sectional view of a main part of a conventional MWD pulse generator, and FIG. 8 is a pulse diagram showing the relationship between the pressure of muddy water and time produced by the pulse generator of FIG. 7. 2... Drill pipe, 2a... Channel, 6... Mine, 7... Mud water bypass passage, 7a... Inflow channel,
7b...Ejection path, 7c...Connection part, 10...Rotary plug, 11...DC servo motor, 12...Communication hole, 12a...Communication hole, 12b...Ejection hole, Mh
...High pressure muddy water, M...Low pressure muddy water.

Claims (1)

[Scope of utility model registration request] A casing is inserted up to the tip of the drill pipe to form a passage for high-pressure muddy water in the space between the drill pipe and the casing, an inflow passage for muddy water is opened in the casing to open into the passage, and a muddy water inflow passage is opened in the casing. A spouting passage is opened for spouting the inflowing muddy water out of the drill pipe near the pit, and a rotary plug is provided at a connecting portion between the inflow passage and the spouting passage, and this rotary plug can be connected to the inflow passage. It has a communication hole and an ejection hole whose one end is connected to the communication hole and whose other end is connected to the ejection passage, and the rotary plug is driven by a driving means housed in the casing to cause the communication hole to flow in. A pulse generator for a continuous bottomhole data telemetry system configured to intermittently communicate with the drill pipe and eject high-pressure muddy water out of the drill pipe.