RU2548463C1 - Formation fracturing method and device for its implementation - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: group of inventions relates to the method and the device for oil production intensification. The method comprises the lowering into a well of a mechanical device making widening effort by means of slips which are widened in a single longitudinal plane of slips towards walls of uncased borehole for cracking. The device is lowered into a horizontal well and is oriented so that the widening effort to be directed up and down. The device for the method implementation contains a housing, a cylinder coupled with the housing, and the contains a working piston coupled with a wedge pusher which is fitted with a pair of slips designed with a possibility of movement with reference to the wedge pusher during interaction with the housing and cross widening in a single longitudinal plane. The device is fitted with one or several additional housings with the wedge pushers and slips which are tandem connected from below to the housing. The wedge pushers are rigidly connected among themselves.

EFFECT: improvement of efficiency of hydraulic fracturing.

5 cl, 2 dwg

Description

The invention relates to the oil and gas industry, in particular to methods for intensifying oil production.

One of the most effective ways to intensify oil production from a reservoir is to break it with the formation of either extended cracks or a network of cracks near the well.

Cracks in the formation are formed when a voltage is created in it that is sufficient for it to rupture or open cracks already existing in it.

A known method of fracturing (RF patent No. 2300629, IPC ЕВВ 43/263, publ. 06/10/2007), according to which a voltage sufficient to fracture or open existing cracks in it, create a descent into the well and burning a powder charge in the interval of various shapes.

Its disadvantages are the lack of focus on the formation of cracks, the lack of the possibility of their fixation, the short duration of the impact, the complex controllability of the process.

There is also a known method of fracturing by creating tearing stress by injecting high-pressure fluid into the reservoir (Economides M., Olini R., Valko P. Unified design of hydraulic fracturing. - Moscow-Izhevsk: Institute for Computer Research, 2007, p. 20).

The disadvantages of the method are the creation of vertical uncontrolled depth of propagation of cracks, often reaching aquifers and flooding the well, the inability to create a horizontal crack and close an unsuccessful crack.

The closest in technical essence to the proposed one is the method of cracking by creating a revealing force in the reservoir using a mechanical device (see AS No. 1456563, publ. 07.02.89 in Bulletin No. 5).

The disadvantage of this method is the inability to create a horizontal fracture, since the method is implemented in a vertical well.

The technical objectives of the proposed method are the ability to create horizontal cracks, exploitation of the crack without fixing it or fixing it with proppant, as well as the possibility of closing the crack.

The stated technical problems are solved by the method of fracturing, including the descent into the well of a mechanical device that creates a spreading force using transversely extensible in the same longitudinal plane dies on the walls of an uncased well to create cracks.

What is new is that the device is lowered into a horizontal well and oriented so that the spreading force is directed up and down.

What's new is that cracks are fixed with proppant.

Also new is the fact that two or more devices are sequentially lowered into a horizontal well, from the bottom of the well to the wellhead, the devices being positioned relative to each other at a distance that allows the resulting fractures to connect with each other.

To implement the method, you need a device that allows you to apply mechanical force to the walls of an open horizontal wellbore.

A device is known (RF patent No. 2287664, IPC ЕВВ 33/13, published on November 20, 2006) containing hydraulic cylinders with pistons and a wedge mechanism with dies interacting with the walls of the well.

The disadvantages of the device are the action of the dies in all directions around the circumference and the irregular shape of the dies.

The closest in technical essence to the proposed is a device (RF patent No. 2395671, IPC ЕВВ 43/112, publ. 07.27.2010), containing several hydraulic cylinders, as well as a wedge pusher with twin dies made with the possibility of radial expansion.

The disadvantage of this device is the small length along the axis of the borehole produced by the fracture.

The technical task of the proposed device is to increase the length of the created crack.

The stated technical problem is solved by a device for implementing the method of fracturing, comprising a housing connected to a housing, a cylinder in which a working piston is connected to a wedge pusher, which is equipped with paired dies made to move relative to the wedge pusher when interacting with the housing and transverse to one longitudinal plane.

New is the fact that it is equipped with one or more additional cases with wedge pushers and dies, connected in series from below to the case, and wedge pushers are rigidly interconnected.

Also new is the fact that on one side of the casing, each die is equipped externally with a longitudinal pointed protrusion, and on the other side of the casing it is rounded to the inside diameter of the well.

The essence of the invention lies in the fact that with the help of a device lowered into the open hole of a horizontal well, forces are created that push the opposite walls of the well up and down. This creates a tensile stress in the vertical plane, the plane along the axis of the well, leading to the formation of a horizontal crack and the opening of existing horizontal cracks.

The advantage of a horizontal fracture is that it will propagate through the formation and create a large filtration surface without spreading to higher or lower aquifers.

In FIG. 1 shows a diagram of a device for implementing the method of fracturing.

In FIG. 2 shows a diagram of a device for implementing a fracturing method with dies equipped with pointed longitudinal protrusions.

The device (Fig. 1) contains a cylinder 1 placed coaxially or parallel to the axis of the well 2, a wedge pusher 3 rigidly connected to it, a housing 4 with windows 5, in which there are dies 6 interacting with the wedge pusher 3. A piston 7 is placed inside the cylinder 1 , the hollow rod 8 of which is in communication with the process pipes 9 and the hole 10 with the under-piston space 11, and the over-piston space is communicated with the hole 12 with the cavity of the well 2. The rod 8 is connected by a rod 13 passing inside the wedge pusher 3 with the bottom 14 of the housing 4. The outer surface 15 p pit 6 is made cylindrical with a radius equal to the radius of the well 2 and the maximum contact area with its surface (section AA) or pointed with a sharp edge 16 parallel to the axis of the device (Fig. 2). Well 2 is drilled in formation 17 in which a fracture 18 is created.

The device can also be implemented in a mixed version, when dies 6 with a cylindrical outer surface 15 are placed on one side of the housing 4, and on the other hand with a pointed outer surface 16.

The device shown in FIG. 1, works as follows.

After lowering it into a horizontal well 2 on technological pipes 9 at a predetermined interval so that the wedge pusher 3 and dies 6 are in a vertical plane, liquid is injected into the pipes 9 under pressure. The fluid along the hollow stem 8 enters the space 11 under the piston 7, which moves towards the wellhead 2 (conditionally, up), displacing the fluid located above the piston 7 through the hole 12 in the wall of the cylinder 1 into the cavity of the well 2. In this case, the piston 7 pulls through the rod 8, the rod 13 and the bottom 14 of the housing 4 upwards, which drags the dies 6 upwards with the edges of the windows 5. The latter, interacting with the wedge pusher 3, rigidly connected to the cylinder 1, extend radially outward against the stop in the borehole walls 2. With a further increase pressure fluid injection dies 6, upir Having the outer surface 15 in the walls of the borehole 2, a sufficient pressure is generated in the formation 17 to rupture it, and a crack forms 18. After the formation of a crack 18, the fluid is stopped, the dies 6 remain on the wedge follower 3 in the same position due to self-braking on the wedge surface and crack 18 is in the open state. Further, after conducting research, the cylinder 1 with the piston is disconnected from the wedge pusher 3 and the well is operated with an increased production rate. If the fracture 18 has fallen into the aquifer of the formation, the device is completely removed, and the fracture 18 closes.

A crack 18 is formed in a plane perpendicular to the plane of the dies 6, only horizontal.

The device of FIG. 2 basically works the same as the previous one, but the break mechanism is different. Therefore, the device is installed in a horizontal well 2 in such a way that the wedge pusher 3, dies 6 and their points 16 are located in a horizontal plane. Since the outer end 16 of the dies 6 is made pointed and wedge-shaped, they, under the action of the wedge pusher 3, cut into the walls of the well 2 and push the formation rock 17 apart in different directions, like a wedge splits a log.

Fracturing and formation of a crack 18 occurs in the plane of the tip 16 of the die 6 in a horizontal well.

When using mixed dies, the device is oriented in the same way as with pointed dies 16. In this case, horizontal cracks 18 are formed only on one side of the well 2, where there are dies 6 with pointed ends 16.

The device does not exclude the possibility, if necessary, for example, if it interferes with any work in the well and needs to be removed, the crack 18 should be fixed by pumping proppant into it. If the forces developed by one cylinder 1 are not enough, several cylinders 1 and pistons 7 are connected in series using hollow rods 8 so that their forces add up.

To create cracks longer along the well, several devices can be sequentially lowered into the well, leaving the previous or its wedge part in the well. In addition, the device can be performed with sequential actuation of the wedge-expanding units so as not to divide the force developed by cylinder 1 into several.

Thus, the proposed method, carried out using the proposed device, has the following advantages.

1. The ability to hold cracks opened by the device without fixing them with proppant.

2. Adjustable crack width and length.

3. The possibility of creating a horizontal fracture in a horizontal well.

4. The ability to close a crack if it falls into the aquifer.

Claims (5)

1. The method of fracturing, including the descent into the well of a mechanical device that creates a spreading force using transversely sliding in the same longitudinal plane of the dies on the walls of the uncased borehole to create cracks, characterized in that the device is lowered into a horizontal well and oriented so that the spreading force was directed up and down. 2. The method of fracturing according to claim 1, characterized in that the cracks are fixed with proppant. 3. The method of fracturing according to claim 1 or 2, characterized in that two or more devices are sequentially lowered into the horizontal well from the bottom of the well to the wellhead, the devices being positioned relative to each other at a distance that allows the resulting fractures to connect together. 4. The device for implementing the method of fracturing, containing a housing connected to the housing of the cylinder, which houses the working piston connected to the wedge pusher, which is equipped with paired dies, made with the possibility of movement relative to the wedge pusher when interacting with the body and transverse extension in one longitudinal plane, characterized in that it is equipped with one or more additional buildings with wedge pushers and dies, connected in series from below to the body, p Weigh wedge pushers are rigidly interconnected. 5. A device for implementing the method of fracturing according to claim 4, characterized in that, on one side of the body, each die is equipped externally with a longitudinal pointed protrusion, and on the other side of the body is rounded to the inside diameter of the well.

Images