MIXING SYSTEM AND METHOD FOR PRODUCING A DRILLING FLUID FOR GROUND DRILLING AND USE IN PRODUCTING A DRILLING FLUID FOR GROUND DRILLING

Abstract

A mixing system for producing a drilling fluid for ground drilling includes a feed for a powdered medium and a mixing chamber with a feed for a fluid medium. A space is provided between the feed for the powdered medium and the mixing chamber, having sliding elements therein, which sliding elements can seal off the space at one end.

Claims

1. A mixing system for preparing a drilling fluid for ground drilling with a feed for a powdered medium and a mixing chamber with a feed for a fluid medium, wherein a space is provided between the feed for the powdered medium and the mixing chamber, wherein sliding elements which can close off the space at the end are present.

2. The mixing system according to claim 1, characterized in that the feed for the fluid medium is arranged in the area of the mixing chamber at the end toward the space.

3. The mixing system according to claim 1, characterized in that a sensor is provided in the end region of the space toward the feed of the powdered medium.

4. The mixing system according to claim 1, characterized in that a feed for fluid medium mixed with powdered medium is provided on the mixing chamber and/or a feed for a polymer is provided on the mixing chamber.

5. A method for preparing a drilling fluid for ground drilling, wherein a powdered medium is mixed with a fluid medium, comprising the steps of providing a space between a feed for the powdered medium and a mixing chamber, which has a feed for the fluid medium, wherein the space is opened and closed off by means of two sliding elements.

6. The method according to claim 5, characterized in that powdered medium is introduced into the space by means of a feed screw.

7. The method according to claim 5, characterized in that a mixer is driven to rotate in the mixing chamber.

8. The method according to claim 5, characterized in that the fluid medium is supplied at a pressure below 3 bar.

9. The method according to claim 5, characterized in that the sliding element between the mixing chamber and the space is first closed in a step at the beginning, and the space is filled with powdered medium.

10. The method according to claim 5, characterized in that in supplying a ground drilling device with drilling fluid, first the sliding element to the mixing chamber is closed, the powdered medium is supplied rapidly to the feed of powdered medium with the sliding element open, and on reaching a predetermined amount of powdered medium between the feed and the space, the sliding element to the mixing chamber is opened.

11. The method according to claim 5, characterized in that the sliding element for the feed of powdered medium is closed and the feed is terminated on ending a supply of drilling fluid to a ground drilling device, and the sliding element between the space and the mixing chamber is open.

12. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWING

[0038] The invention is described in greater detail below on the basis of an exemplary embodiment, which is illustrated in the drawing.

[0039] FIG. 1 shows a schematic diagram of a mixing system.

DETAILED DESCRIPTION

[0040] FIG. 1 shows a schematic diagram of a mixing system 1. A supply tank 2 in which bentonite can be stored is provided. A feed 2a into a feed space 3, where a feed screw 4 is situated, is provided on the end of the supply tank 2. The feed space 3 is designed in a tubular shape. The outside diameter of the feed screw 4 corresponds essentially to the inside diameter of the feed space 3. The feed of the powdered medium and/or the end of the supply tank 2 is/are connected to the outer pipe of the feed screw 4. The feed screw 4 is connected to a drive 5, with which the feed screw 4 can be driven.

[0041] The feed space 3 may be in fluid connection to a space 6, wherein the connection between the feed space 3 and the space 6 can be interrupted by means of a sliding element 7. The space is designed in a tubular shape and has essentially the same diameter as the feed space 3. The space 6 is an extension of the feed space 3. The central axis of the space 6 is essentially on the central axis of the feed space 3.

[0042] The fluid connection between the feed space 3 and the space 6 is selectively separable by means of the sliding element 7. When the sliding element 7 is open, powdered medium can be conveyed into the space 6 and subsequently into a mixing chamber 8 by means of the feed screw 4.

[0043] A sliding element 9, with which the connection between the space 6 and the mixing chamber 8 can selectively be interrupted, is also provided between the mixing chamber 8 and the space 6. The sliding elements 7, 9 may selectively be brought into a closed position or an open position. Independent movement of the sliding elements 7, 9 is possible. The sliding elements 7, 9 can be moved by means of an electrical or electronic drive 10 and/or 11, respectively.

[0044] The mixing chamber 8 is designed in the form of a tube. The mixing chamber 8 is an extension of the space 6. The central axes of the mixing chamber 8 and the feed chamber 3 essentially coincide.

[0045] A mixer 12 is arranged in the mixing chamber 8. The mixer 12 is arranged in the mixing chamber 8 in such a way that the mixer 12 is provided for rotating at the center of the mixing chamber 12 by means of a drive 13 at the center. The axis of the mixing chamber 12 corresponds essentially to the central axis of the mixing chamber 8. The rotational speed of the mixer 12 is adjustable independently of the rotational speed of the feed screw 4.

[0046] The mixing chamber 8 is provided with a feed for fluid medium. Furthermore, a feed 15 for drilling fluid 15 that is already present is provided on the mixing chamber 8. Another feed 16 for a fluid medium, for example, recycled drilling fluid, is also present.

[0047] A feed 17 for a polymer is provided in the rear area of the mixing chamber 8.

[0048] The mixture of powdered medium and fluid medium can be discharged from the mixing system 1 through a drain 18.

[0049] To empty the supply tank 2, an agitator 19, which may have a belt drive, is provided. The belt drive may be connected to the drive 5.

[0050] A sensor 20, which can monitor the filling level of the supply tank 2 with regard to the powdered medium, is provided on the supply tank 2. A sensor 21 for powdered medium, which is provided at the end of the feed space 3, can verify whether and how much powdered medium, i.e., whether there is enough powdered medium in the feed space 3.

[0051] Operation of the mixing system 1 is as follows:

[0052] For startup of the mixing system 1, the sliding element 9 may be closed, and the sliding element 7 may be opened. The feed 14 for the fluid medium may be opened, and the drive 5 of the feed screw 4 is started when the sensor 21 signals that enough powdered medium is present in the transition between the feed space 3 and the space 6. Then the sliding element 9 is opened and the drive 13 of the mixer 12 is turned on. Preparation of drilling fluid may begin by means of the procedure described here to prepare the mixing system.

[0053] In further preparation of drilling fluid, the sliding element 9 is first closed and the sliding element 7 is opened, so that the drive 5 for the feed screw 4 is rotated at a high rotational speed until the sensor 21 indicates that enough powdered medium is present, i.e., the space 6 has been filled to a sufficient extent. The sliding element 9 then opens and the drive 5 of the feed screw 4 is set at a lower rotational speed.

[0054] The ground drilling is stopped and/or the mixing of drilling fluid is stopped by closing the sliding element 7 and stopping the drive 5 for the feed screw 4. The sliding element 9 is open and the drive 13 of the mixer 12 is turned on. The mixing chamber 8 can then be emptied.