NO20101487A1 - Device for operating downhole equipment - Google Patents

Abstract

It is referred to as a device for generating a pressure pulse to activate a fluid pressure activating equipment in a tube (12/27), and it is characterized in that the tube (27) comprises a flexible membrane (24) which isolates the fluid F1 in the fluid-carrying tube from a fluid F2 in a second channel communicating with the equipment which, based on its elasticity, transmits pressure changes (pressure pulses) in the fluid P1 in the tube (12) to the fluid P2 in the second channel (30). Preferably, the second channel (30) is fluidly connected to a chamber (26) in which the diaphragm (24) is disposed and the diaphragm (a bellows) (24) is extruded outside the tube section (27) and arranged in a chamber-forming (26) seat in the pipe section (27), the wall of the pipe section comprising a plurality of through-bores for producing fluid communication from the fluid F1 with the pressure P1 in the pipe (27) radially outwardly against the membrane located on the outside of the pipe wall. The diaphragm (24) is preferably a sleeve-shaped bellows, and the chamber forms an annular shape around the perimeter of the pipe section, and the pipe wall comprises a plurality of through bores around the entire perimeter of the pipe.

Description

Device for operating downhole alignment

The present invention relates to a new construction of a device for producing a pressure pulsation in a well, as is evident from the introduction in the following claim 1. In particular, the invention relates to a construction which can contribute to operating downhole equipment that is hydraulically operated.

It has long been known that in connection with pressure pulsing to activate mechanical equipment installed down in an oil or gas well, there are challenges associated with getting these pressure pulses to the equipment.

This is especially the case when the pipe itself which is led down into the well is pressurized to send these pressure signals down to the equipment. The problem is that you very often find that, over time, precipitates of particles form and accumulate in the liquid, so that eventually a solid mass forms at the bottom of the pipe, when such particles sink to the bottom. This is particularly a problem when plugs are used in the production pipe, which are operated in such a way that pressure is pumped up over the plug from the rig.

One way to limit the problem is to connect the equipment to a hydraulic control line (a line) that is outside the existing pipe in which the plug is mounted. Such control lines are led up and through the wellhead installation and further up to the rig so that it can be pressurized directly from the rig, and consequently still operate the equipment even when mud accumulates above the plug in the pipe.

The disadvantage of such a system is that it greatly increases the cost of operations and that with the construction of a control line (wire) several kilometers long, it introduces a risk as it is likely that the pipe, which is generally and for example a thin pipe with a dimension of 1/4", wears off against the walls of the well, and you can then lose all control of the equipment.

A known solution is to use a type of accumulator where clean liquid is brought down into the well. Such a solution is described in Norwegian patent application no. 2008 0452. There, an accumulator is described which has a limited volume to supply the equipment with a clean bag for and operate it.

What is described in the Norwegian application is a piston accumulator which, according to the description, accumulates pressure while driving into the well.

This system still leads to a good number of problems associated with the functionality.

First of all, it is claimed that debris (deposits of impurities) cannot enter the system. But this is wrong as, by blocking the channel into the upstream piston described, you will not be able to supply the pressure pulses that are required for the system to function. It is true that these particles will not contaminate the bag that is downstream of the piston that will affect the cyclus mechanism in the system, which will open on a predetermined number of pressure impacts. The problem is that with fluid communication through the channel upstream of the piston, particles can be brought into the chamber and thereby the piston is blocked from moving so that a pressure difference can occur between the piston upstream and downstream.

A syclus system based on pressure differences will then stop working.

It is a main purpose of the invention to produce a new construction which can solve the above-mentioned disadvantages and problems.

The solution according to the invention includes installing a flexible diffusion-free membrane, such as rubber, in a separate housing/sleeve section of the pipe). With such a solution, a completely different effect can be achieved than in the previously known solutions.

The device according to the invention is characterized by the features that appear from the characteristic in claim 1, and the preferred embodiments appear from the independent claims.

One of the advantages of the present invention as defined is that a piston that moves axially in the longitudinal direction will be limited in area that can be affected, while a bellows that moves radially will be able to have an enormous area that is affected. This area is limited only by the length of the bellows.

The invention will be explained in more detail with reference to the subsequent figures.

Figure 1 shows a pipe that is lowered in a borehole in, for example, a hydrocarbon-bearing formation, and where the inventive device is used. Figures 2 and 3 show the details of the inventive construction 10 in two positions, this being arranged a little upstream of the downhole equipment 20 which is to be operated hydraulically according to the invention. Figure 3B shows a cross-section of a hole arranged in a radial direction through the pipe wall. Figures 4 and 5 show an enlargement from Figures 2 and 3, and show the hydraulic channel 30 through the pipe wall and which connects the pressure pulsating device 10 with the equipment 20. The figures show a pipe 12 which is reduced in a borehole 14 in a formation 16. Described as a non-limiting example, a pipe section 18 is fitted at the bottom of the pipe with a seat that accommodates a plug 22. The plug 22 is used, for example, initially to test and check that the inside of the pipe is sufficiently tight under pressure, and will function as intended under production of hydrocarbons from the formation 16.

Since large layers 25 of impurities of solid particles such as sludge can accumulate on top of the upward-facing plug surface 23, the device 10 is placed a little above the plug 20, and the plug 20 and the device 10 are connected by a channel 30 which runs axially along and through the pipe wall between these two areas.

The device comprises a perforated pipe section 27 which is inserted into the pipe 12. A cavity or chamber 26 is defined between the section's outer wall 21 and the pipe 12's inner wall.

Enclosing, a sleeve-shaped elastic bellows or membrane 24 is threaded on the outside of the pipe section 25, and which at the top at 31 and at the bottom at 33 is fixed in the wall material in the pipe section 25. The bellows 24 can consequently be bulged out from a position where it lies almost glued to the outer wall 21 of the pipe section and to which it bulges out and lies against the inner wall 13. Outside the bellows 24, the annular chamber 26 is connected to a bored out channel 30 which runs through the pipe wall downwards to the release mechanism (not particularly shown here) which is used to blow away the plug. The setting or bulging of the bellows will depend on the difference in the pressure P1 inside the pipe 12 and the pressure P2 in the chamber and channel 30 outside the membrane 24. Figure 2 shows the situation where the pressure P1 is higher than the pressure P2 (P1 > P2) so that the membrane bulges out.

Figure 3 shows the situation where P2 is higher than or equal to P1 and the membrane lies more wavy next to the outer wall 21.

The trigger mechanism that removes the plug is arranged so that it counts a number of pulses where the fluid pressure P1 is increased and lowered, and where the plug is blown away on a predetermined number of pulses.

In the chamber radially outside the bellows, a clean bag is filled which is connected to an external pipe or the internally drilled channel 30 which in turn is connected to, for example, a pressure pulse-sensitive valve.

The pressure-sensitive valve can be set or set up to either read the signals electronically using a pressure transmitter or it can be a purely mechanical system that reads the pressure pulses and then opens the valve on a predetermined number of pressure impulses.

When the valve opens, the clean liquid will flow past the valve and operate the hydraulically operated equipment. The technique can be used to operate all downhole equipment that is hydraulically operated, and requires a clean bag to be operated correctly. Examples of such equipment can be detonation systems for removable (disappearing) plugs, sliding sleeves, hydraulically operated ball valves and hydraulically operated flapper valves. These are just a few examples of equipment that this new technological solution can be used for. The hydraulically operated system can, for example, be a layered plug 22 made of glass. How it is removed or crushed is not specifically shown in the figures. The pressure pulse-controlled device can comprise a device 39 which can count the number of pulses, and when it has counted the correct number, the mechanism is triggered and triggers the blasting mechanism. This can mean, for example, that an axially directed piston 38 in the pipe wall is pushed downwards with great force and pushes a horizontally directed crushing piston in a radial direction into the plug 22, which can thus crush. The plug can be made of breakable ceramic or of glass adapted for this purpose.

By using a bellows instead of a piston, it will also be possible to drill a large number of holes radially through the wall of the protective sleeve which holds the bellows and the clean liquid in place. A cross-section of one of these drilled holes 50 in the radial direction through the pipe wall 26 is shown in the section in Figure 3B. On both sides of a central concentric bore 56, a gradually widened hole shape 52 and 54 is drilled so that it forms a trumpet shape, with the widest cross-section at the wall.

The risk that holes with this design can be blocked by debris and solid particles and mud is reduced by the fact that the holes are drilled concentrically in both directions. This hole shape through the wall, with concentric drilling shape both ways, will lead to an effect where you will always have fluid/liquid flow both ways as particles that are stuck in a conical hole that opens up with the largest diameter on the opposite side of the one affected by pressure will help particles to loosen when pressure is applied from the side with the fewest holes. A particle 60 in the pipe fluid, which had to get stuck and block the inlet to the bore 56, when the fluid F1 flows in the direction of the arrow P2, will easily detach and be pushed back again when the pressure P2 exceeds P1 and the fluid F2 flows back. The particle 60 will be detached by the backflow.

Furthermore, with the introduction of a burst disk that is set to burst or burst at, for example, a 10 bar differential pressure between the pressure in the clean liquid behind the flexible material and the bag in the well pipe, we can further ensure that a pressure difference does not occur between the two the liquids. The flexible membrane will also always cause equal pressure to occur on both sides and return to its original shape after a pressure effect.

The burst disc is placed at the top of the tube where the bellows is mounted, to provide communication if too high pressure builds up on the back (P2) of the bellows which is not equal to the pressure P1 inside the tube (tubing).

The burst disc can basically be placed anywhere as long as it is positioned so that it separates the fluid between the tubing and the back of the bellows and creates communication between them when it bursts.

The burst disk will also assist any operation of equipment to be controlled by refilling with well fluid when the clean fluid behind the membrane is used up; and the membrane is pressed against the walls of its respective housing, a pressure difference will arise between the well pipe (P1) and the back (P2) of the membrane, after which the burst disk will burst and liquid from the well will be refilled into the system.

There are thus many advantages compared to, for example, known technology which has limited volume, limited surfaces that can be affected by the pressure, as well as the risk of jamming of the system, etc.

Claims (9)

1. Device for generating a pressure pulse to activate a fluid pressure activatable device in a pipe (12/27), characterized in that the pipe (27) comprises a flexible membrane (24) which isolates the fluid F1 in the fluid-carrying pipe from a fluid F2 in a second channel which is in fluid connection with the equipment, which membrane, based on its elasticity, mediates pressure changes (pressure pulses) in the fluid P1 in the pipe (12) to the fluid P2 in the second channel (30). 2. Device in accordance with claim 1, characterized in that the second channel (30) is fluidly connected to a chamber (26) in which the membrane (24) is arranged. 3. Device in accordance with claims 1-2, characterized in that the membrane (a bellows) (24) is threaded on the outside of the pipe section (27) and arranged in a chamber-forming (26) seat in the pipe section (27), which wall of the pipe section comprises a number through bores to create fluid connection from the fluid F1 with the pressure P1 in the pipe (27) radially out towards the membrane located outside the pipe wall. 4. Device in accordance with one of the preceding requirements, characterized by the diaphragm (24) is a sleeve-shaped bellows, and the chamber forms an annular shape around the circumference of the pipe section, and the pipe wall includes a number of continuous boreholes around the entire pipe circumference. 5. Device in accordance with one of the preceding claims, characterized in that each bore 50 through the pipe wall defines a central concentric bore 56, with each end of the bore (56) forming a trapezoidal extension facing the pipe's inner wall 121 or outer wall 21. 6. Device according to one of the preceding claims, characterized in that the flexible membrane produces an equal pressure on both sides of the membrane, which will, for example, fold, stretch and fold back to its original shape after a pressure effect. 7. Device in accordance with one of the preceding claims, characterized in that a burst disc is arranged in the pipe (12/27) to define a removable dividing plate between the two fluid areas F1 (pressure P1) and F2 (pressure P2). 8. Device in accordance with one of the preceding claims, characterized in that the burst disc is arranged to burst at a given pressure difference between the fluids F1 and F2, for example when a pressure difference of 10 bar occurs between the two areas, in order to thus secure the system against further against a pressure difference occurring between the two liquids. 9. Device in accordance with one of the preceding claims, characterized in that the burst disk is placed at the top of the pipe (12/27) where the bellows (24) is mounted, to provide communication if too high a pressure builds up in the fluid F2 at the back (P2) of the bellows and which is not equal to the pressure P1 in the fluid F1 inside the pipe (tubing).