EP1632640B1 - Method and apparatus for filling a drill string with a drilling fluid - Google Patents

Abstract

An oil or gas drilling rig has a filling assembly to feed a drilling lubricant/coolant to a drill tip and comprising a cylinder (1) with a valve-controlled fluid inlet (3) and a piston chamber (5). The cylinder has an end-piece (2) with a link fitting to a drill rod drive. The cylinder further has a hollow cylindrical filling piston (9) delivering fluid to the drill string inside the chamber (5). The filling piston moves back and forth axially and has an outlet that is opened and closed by a piston valve (4) and regulates discharge of the drill fluid.

Description

The invention relates to a filling device for filling of drilling fluid in drill pipe or in Bohrzüge a drill string, as used in oil or gas wells and a method for their operation.

In the operation of drilling rigs for deep drilling, in particular for the development of oil or natural gas deposits drilling methods are used in which drilling fluid are filled in certain compositions in the drill pipe of a drill string and directed to the drill head. For this purpose, the individual drill pipe are formed as a hollow cylinder and provided at the ends with openings for the passage of drilling fluid to the drill head.
By means of pumping means in the region of the platform, the drilling fluid is conducted during the drilling process through the drill pipe into the borehole and sprayed through the nozzles arranged at the drill head under high pressure in the borehole. The resulting in drilling operation cutting residues are thus continuously removed from the teeth of the cutting tool and secured its necessary cooling.
The fluid level should fill the cavity of the borehole as completely as possible and reach to the surface of the drilling platform. Because in addition to the extremely important reduction in the friction losses of the drill string, the drilling fluid also protects against uncontrollable gas leakage, so-called blow-outs and serves to transport the cuttings from the bottom of the well in Bohrschlammauffangvorrichtungen the drilling platform.

The drill string itself consists of a plurality of coupled drills, which in turn comprise a plurality of drill pipes.

Depending on the drilling progress achieved and the final depth of the well to be achieved, the drill string must be continuously extended by new drill string. The drill pipes are combined into drills and transported by the elevator on the platform to the well and coupled to the drill string. In order to maintain the necessary drilling fluid level in the well, which is also important for an effective circulation of the drilling fluid, drilling fluid must be supplied with the extension of the drill string.
After completion of the drilling operations, the drill string is removed from the wellbore in most cases and casings used to stabilize and line up the wellbore.

In particular, for cost reasons, it is desirable to perform the individual steps in the extension of the drill string and maintaining an optimal Bohrflüssigkeitspegels in the borehole with minimal expenditure of time and a user-friendly and reliable technique.
This goal has been subjected to numerous development work in the drilling technique. Particular emphasis is also placed on the tools and technical aids described in detail in the patent literature, which are used for filling and circulating the drilling fluid.

Here, the design optimization, the trouble-free, operating time, as well as the procedural minimization of changeover times of the developed tools are given special attention.

For example, many devices have been proposed which allow simultaneous filling of the drill string and the circulation of drilling fluid between the drill string and the casing. Such known Auffüllvorrichtungen are usually housed in cylindrical housings, with a pressure-actuated and displaceable in the axial direction valve for opening and closing the conduction path of the drilling fluid in the drill pipe.
For filling of casings of a drill string so-called filling valves are usually coupled to the drill string and partially lowered into the filled with drilling fluid casing, where then supplied by pumping drilling fluid is dispensed via differently designed closable openings and nozzles in the annulus between the drill string and casing , The filling valve also prevents the undesired backflow of contaminated drilling fluid, also called drilling mud, into the drill string after the pump is shut off.

Some technical solutions use tools that are advantageously connected to the topdrive of the drilling rig, in particular screwed and also have a pressure-actuated inlet valve that is opened by the flowing drilling fluid.
So will in the EP 929731 B1 discloses a very complex filling and circulating device for drilling rigs, which describes the partial filling of casings in a well with drilling fluid. In this case, the drilling fluid is added by means of a hooked into the drill tool filling each feed pipe to be used. The liquid inlet via inlet nozzles, which are protected by a Bohrschlamm valve device against the temporarily out of the wellbore drilling mud. This known auxiliary tool should also allow the circulation of the drilling fluid and the cementing of the casing in the borehole. The multi-functional capability to be achieved, however, requires a complicated structure and a high susceptibility to failure of the device.
From the EP 774564 A2 Also, a drilling fluid refilling apparatus is known which discharges the drilling fluid into the freed annulus between the drill string and the walls of the wellbore.
The cylindrical filler described herein is bolted to the topdrive of the elevator and the tubular drill string. The cylindrical walls provided with one or more laterally arranged outlet openings for the drilling fluid to be dispensed can be closed by a valve slidable between two positions.
The refilling device is also used for cementing casings and must be lowered both for filling the well with drilling fluid, as well as for cementing in the well.
In the next state of the art to be considered US 6460620 B1 a filling device for filling a deep drill string or one or more drill trains is described with drilling fluid. This filling device consists of a cylindrical body, which has a piston chamber with at least one Includes filling opening for drilling fluid and an end piece, which has connecting means and is used for coupling to the top drive of Tiefbohrstranges. In this case, a hollow cylindrical filling piston for discharging drilling fluid into the drill string in the piston chamber of the cylindrical base body is arranged to slide axially movable. However, the filling opening described here is not closable and there is also no device provided with which the hollow cylindrical filling piston can be opened and discharged for dispensing drilling fluid.
Other generic filling devices are also in the US 2002/0189814 A1 and the EP 939193 A2 described.

All of these previously known devices, whether only for filling or for combined filling and circulation of drilling fluid, have numerous disadvantages.
So is often a time-consuming procedure for coupling and decoupling of known filling tools and auxiliary equipment to the drill pipe or Bohrzug necessary, as well as a complicated and prone to failure lowering into the well. Also, with these facilities no filling of the coupled towing drills during their installation in the drill string possible.
The dirty with backwash drilling mud and slidably arranged valve parts, and their outlet openings clog and need time consuming cleaning.

It is therefore an object of the present invention to provide a device and a method for their operation, with which these disadvantages are eliminated and a fast, time-saving and reliable filling of Bohrzügen is ensured with drilling fluid.

This object is achieved by the filling device according to the invention according to the characterizing features of claim 1.

In the subclaims further advantageous embodiments and further developments of the invention are given.

The inventive solution relates to a filling device for filling a drill string, drill pipes or drills with drilling fluid.

Essential components of the inventive solution are a cylindrical body comprising a piston chamber with at least one closable filling opening for drilling fluid and having an end piece for coupling the filling device to the Topdrive (rotary drive head) of the Tiefbohrstranges. The inventive filling device is further characterized in that a hollow cylindrical filling piston for discharging drilling fluid into the drill string in the piston chamber of the cylindrical base body is arranged to slide axially movable.
In the cavity of the filling piston also engages an axially movable piston valve and cooperates with the piston chamber such that caused by the Bohrflüssigkeitsdruck opening position and caused by an external media pressure, in particular compressed air closing positions is ingestible and effective.

The device of the invention is preferably used to fill up drills or drill pipes with drilling fluid during their installation to reposition the drill string.
For this purpose, the filling device is mounted on the drilling platform in the coupling device of the elevator and connected to the pump system for the supply of drilling fluid, and an external pressure medium source for actuating the filling valve.
With this device according to the invention it is not necessary to lower the "filling opening" of the tool into the borehole or casing or to couple it to the drill string,
which leads to considerable time savings when repositioning the drill string

Details of the invention will now be explained in more detail with reference to drawings and an embodiment.

• Fig. 1 Die erfindungsgemäße Fülleinrichtung in der Öffnungsstellung
• Fig. 2 Die Fülleinrichtung bei geschlossenem Füllkolben 9

Show it:

• Fig. 1 The filling device according to the invention in the open position
• Fig. 2 The filling device with closed filling piston 9

The embodiment relates to the filling device according to the invention and a method for its operation for filling of drilling fluid in a Bohrzug which serves to extend the drill string during installation. Depending on the drill hole depth to be achieved, this process must be repeated very frequently. The frequency of the drill string to be used and replenished for the extension of the drill string, as well as the changeover time required therefor, are optimization variables that can be influenced by the technique used. The individual drill pipe or drill string combined into a drill string are then hooked into the elevator, coupled to the downhole drill string, and lowered into the wellbore.

For coupling to the top drive of the elevator, the filling device according to the invention is screwed to an intermediate piece of light. For this purpose, the cylindrical basic body 1 of the filling device is provided with an end piece 2 which has a coupling means formed with a corresponding screw thread (FIG. Fig. 1 ).
The filling device furthermore has a connection 10 for the supply and the discharge of printing media 16. As printing medium, compressed air is generally used on drilling platforms for easy availability.
The external controllable compressed air source, which is designed in particular as a pneumatic control unit, is then connected by means of compressed air hose to the terminal 10 of the filling device and secured against rotation.

The connection valve 10 for the compressed air is connected via a pressure channel with the gas-tight closed cylindrical space between the outer surface of the filling piston 9 and the inner surface of the piston chamber 5 m.

Further components of the filling device which are essential to the invention are also the piston valve 4 arranged in the base body 1 and the hollow cylindrical filling piston 9 cooperating with the piston valve.
The piston valve 4 comprises an inlet-side valve disk 6, which are arranged together with an outlet-side valve plug 7 at a certain distance from one another on a valve guide rod 8. The valve guide rod 8 extends on the inlet side through the filling opening 3 in the stop / valve seat 14 and is connected to a disc via which a restoring force for closing the valve disk 6 of the piston valve 4 is exerted by the valve return spring 11 disposed between the disk and the valve seat 14.
The arranged at the outlet end of the valve guide rod 8 valve plug 7 is dimensioned and provided on its circumference with inner sealing lips that it can penetrate into the opening of the hollow cylindrical filling piston 9 and this can close.
The tubular filling piston 9 is itself arranged axially slidably in the piston chamber 5 and formed on the inlet side as an annular stop 12 with a groove, which closes gas-tight and media-tight with the inner wall of the piston chamber 5.

In the following, the operation of the filling device according to the invention will be explained in more detail.
After coupling the filling device to the Topdrive of the drill string means Schonstück (4 1/2 IF), the connection of the Bohrflüssigkeitszuleitung and the compressed air via the connection valve 10, the compressed air space between the outer filling piston 9 and the inner wall of the piston chamber 5 is relieved, so that the filling piston 9 moves out in the outlet direction to the pipe opening of the Bohrzuges from the base body 1 and the valve plug 7, the outlet opening of the filling piston releases. On the pneumatic control unit (not shown) the corresponding lever must be set to the "Piston down" position.
Now, the annular pump for supplying the drilling fluid to start in the state and the flowing through a pressure hose, the Topdrive and the Schonstück drilling fluid opens against the spring force of the valve return spring 11, the valve plate 6 and the filling opening 3 of the piston chamber 5 free.

Thus, the drilling fluid passes through the piston chamber 5 into the tube opening of the filling piston 9 which forwards them into the drill train to be filled.

The filling piston is, for example, pushed down by a flushing pressure of the drilling fluid of about 9 bar until the internal piston valve 4 releases the flow path into the hollow filling piston rod 9.

The stroke of the filling piston should be about 60 cm here. However, other stroke parameters corresponding to the design requirements of other drilling rigs are also covered by this invention.
The filling speed with which the drill string is now filled should preferably not exceed 250 l / min.

After completion of the filling and stopping the ring pump closes the valve and leads to the emptying of the piston chamber 10 and the filling piston.

To do this, place the control lever on the pneumatic control unit in the "Piston up" position.
As a result, the filling piston retracts into the piston housing.

Preferably, to avoid spillage of the drilling fluid, a train should remain dry and the volume to be pumped pre-calculated and adjusted at the drilling fluid pumping device.

After completion of the filling operation, the annular pump is switched off on the drilling platform, and there is the automatic emptying of the piston chamber. 5

By actuating the "Piston up" lever of the pneumatic control unit, compressed air is pumped via the connection valve 10 into the piston chamber 5 and the filling piston 9 is moved upwards in the direction of the filling opening 3 (starting position).

Due to the closing movement of the filling piston 9, the valve plug 7 closes the hollow filling piston rod 9 and the valve disk 6 of the piston valve 4 is pressed against the valve seat 14. The closure of the filling opening 3 through the valve disk 6 is also supported by the return spring 11.

For effective and trouble-free. Operation of the filling device is provided in this preferred embodiment, a flushing pressure of the drilling fluid of minimum 9 bar and a compressed air supply to the ring floor of at least 7 bar.

In addition to the ease of use and the fast assembly or disassembly of the filling device and their permanently reliable operation is of particular advantage. The risk of clogging and soiling, as well as the occurrence of malfunctions are minimized by the present constructive inventive solution. Also very advantageous is the time savings to be achieved in the application of the tool according to the invention. Thus, for example, a time saving of one minute and 50 seconds can be achieved per three train to be installed compared to conventional known filling and / or circulating devices.
Particularly advantageous is the use of an external compressed air source for reliable operation of the filling piston. 9
Here, not only the back pressure of the drilling fluid for closing the drill string is used by the piston valve 4, but in addition a strong pneumatic pressure force, which is generated in the cylindrical cavity of the piston chamber 5.
According to the invention, therefore, the filling of new drill trains with drilling fluid already takes place during their coupling to the drill string and during their installation time.

LIST OF REFERENCE NUMBERS

1

cylindrical body

2

End piece of the main body with coupling means

3

fill opening

4

piston valve

5

piston chamber

6

inlet-side valve disk of the piston valve

7

outlet-side valve plug of the piston valve

8th

Valve guide rod

9

hollow cylindrical filling piston

10

Connection valve for pressure medium

11

Valve return spring

12

Ring stop with groove of the filling piston

13

Sealant of the filling piston guide

14

Stop / valve seat

15

Füllkolbenführung

16

Media Connection

Claims (11)

1. Filling system for filling a deep drilling string or one or more drill trains with drilling fluid, comprised of a cylindrical base body (1), that encloses a piston chamber (5) with at least one filling aperture (3) for drilling fluid, a hollow cylindrical filling piston (9) for drawing the drilling fluid into the drilling string or drill train, which is arranged such that it can slide axially in the piston chamber (5) of the cylindrical base body (1) and an end piece (2) which has a joining means and which serves to couple to the topdrive of the deep drilling string, characterised in that the filling aperture (3) can be closed and the hollow cylindrical filling piston (9) with a piston valve (4), is likewise arranged such that it can slide axially in the piston chamber (5), and which work together such that the open and closed positions for drawing in drilling fluid can be taken up.
2. Filling device per claim 1, characterised in that the base body (1) has a connection valve (10) for the feeding or releasing of fluidic or gaseous media, in particular compressed air, into the cylindrical interior between the base body (1) and the filling piston (9) of the piston chamber (5), whereby a pressure-driven movement of the filling piston (9) between the open and closed positions shall be effected.
3. Filling device per claim 2, characterised in that both the base body (1) and also the filling piston (9) have a stop, in particular an inlet-side valve seat (14) and an outlet-side filling piston guide (15), whose arrangement can fix the filling piston stroke between the open position and the closed position of the filling piston (9) in the base body (1), whereby the filling piston guide (15) has a seal (13), which closes the assembly gas-tight and liquid-tight.
4. Filling device per claim 3, characterised in that the piston valve (4) has a valve guide rod (8) with a valve disc (6) and at least one valve plug (7) within a defined distance, which is designed in such a way that it can be inserted into the hollow cylindrical interior of the filling piston (9) in a fluid-tight manner, whereby its closure is enabled and an inlet-side valve return spring (11) located above the stop or valve seat (14) is arranged such that the inlet-side valve disc (6) can be closed against the stop or the valve seat through its spring force.
5. Filling device per claim 4, characterised in that the filling piston (9) is equipped on the inlet side with a ring stop (12), which has at least one circumferential groove to accept a seal, in particular an O-ring, which separates the volume of the pressure medium from the drilling fluid flowing into the piston chamber (5), whereby the valve plug (7) which can be inserted into the filling piston (9) is likewise provided with at least one seal around its circumference, whereby the closure of the filling piston is enabled on the opposite side of the deep drilling string or drill train.
6. Process for operating a filling device per one or more of the claims 2 to 5 characterised in that the end piece (2) of the base body (1) of the filling device is screwed fluid-tight to the topdrive of the drill string and the pressure media feed (16) is linked to the connection valve (10) and the filling of the drill train with drilling fluid is implemented during its integration into the drill string.
7. Process per claim 6, characterised in that to fill a drill train the drilling fluid to be filled into the drill train under pressure opens the piston valve (4) and permeates through the filling aperture (3) into the piston chamber (5), whereby the hydraulic filling piston (9) is pushed downwards in the base body (1) until the outlet-side valve plug (7) of the piston valve (4) opens the flow path into the filling piston (9) and the pre-defined quantity of drilling fluid is filled into the drill train via its outlet aperture.
8. Process per claim 7, characterised in that the pressure of the drilling fluid to be filled in is 8 to 10 bar and the opening stroke of the filling piston (9) is 60 cm, whereby the filling rate of the drill train or the drill string does not exceed 250 l/min.
9. Process per claim 6, characterised in that at the conclusion of the filling process no further feed of drilling fluid occurs through the filling aperture (3) and the piston valve (4) will be closed, whereby the inlet-side valve disc (6) is pressed against the fluid-tight valve seat (14) by means of the valve return spring (11).
10. Process per one of the aforementioned claims, characterised in that, by means of an external compressed gas source, in particular a compressed air generating compressor, compressed gas is routed into the cylindrical interior between the base body (1) and the filling piston (9) via the connection valve (10), whereby the filling piston (9) is moved to its closed position, whereby the valve piston (7) in inserted into the interior of the filling piston (9) and closes this and the valve disc (6) is held against the valve seat (14) by means of the filling piston (9) ring stop (12).
11. Process per one of the aforementioned claims, characterised in that, to prevent the overflow of drilling fluid, at least one drill train of the drill string will not be filled and the filling volume to be pumped will be calculated before the filling and will be regulated by means of adjusting the drilling fluid filling pump, preferably a ring pump.

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