RU2473788C1 - Method of borehole perforation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: at borehole perforation after descending into the borehole the perforator is fixed to prevent turning and shifting. Perforation is made in fixed condition. After perforation is complete the perforator is lifted from the borehole, charged and descended into the borehole again. At borehole perforation after the perforator is again descended into borehole it is fixed in position shifted by azimuth and/or vertically in relation to position it was in at first descending. Repeated perforation is made in fixed condition, after repeated perforation the perforator is lifted from borehole, if necessary the perforation is repeated again.

EFFECT: invention provides combining the place of cumulative perforation action at the second and the following perforation cycles with the place of perforation action at the first perforation cycle, changing the form, extending and deepening perforation holes in the borehole, reducing the negative effect on annulus cement stone at reaching borehole connection with annulus area.

3 cl, 4 dwg, 5 ex

Description

The invention relates to the oil industry and may find application in well perforation by cumulative perforation.

A known method of orienting a firing punch and a device for its implementation, including turning the firing punch after lowering into the well (RF Patent No. 2241823, publ. 2004.12.10).

A well-known set of devices for perforating wells, which contains sections of a perforator, interconnected, casing, support and guide elements. The casing pipe in the wall has horizontal conical holes, protective rings, coaxial with horizontal holes. On the cylindrical surfaces of the bodies of the sections of the punch, there are through grooves consisting of conical and longitudinal parts, while the conical parts of the adjacent grooves form a conical ledge. There are horizontal holes and a vertical axial hole in the case, and a swivel consisting of a sphere and a body assembled from two parts covering the sphere is fixed at the ends of the bodies of the neighboring sections. The horizontal openings of the bodies of the sections of the punch are connected to the sleeve for supplying compressed air by means of a vertical hole (RF Patent No. 2332562, publ. 27.08.2008).

Known hydroperforator. The hydraulic perforator consists of two connected sections. The upper section includes a hollow body, the side walls of which are made with notches. They are made in the form of holders. They have carbide inserts in the form of the main and inverse cones. On the side surface of the main cone, helical grooves are additionally made. On the axial liners made channels. At some distance from the liners, split rings are placed inside the holders. The latch includes a housing with an axial channel and through channels on four tiers. Spring-loaded rods and plugs are installed in through holes. A plug is installed in the axial channel from below. A spring-loaded blind piston is installed on top. The chamber thus formed is filled with oil (RF patent 2038466, publ. 06/27/1995).

Closest to the proposed invention in technical essence is a method of creating perforations in an adjacent subterranean formation from a wellbore, which includes the following operations: placing a downhole perforator in the wellbore containing a group of explosive charges oriented to create perforations in the formation adjacent to well; detonation of a group of explosive charges to create the first perforation hole in the formation and the creation of a pair of second perforation holes intersecting at a point beyond the end point of the first hole (RF Patent No. 2411353, publ. 02/10/2011 - prototype).

All the aforementioned technical solutions allow either to orient the perforator in the well, or to carry out a complex perforating action during one perforation cycle, i.e. for one descent of the puncher. Perforation is carried out without fixing the perforator in the well. However, in one cycle of perforation, i.e. for one descent of the perforator into the well, it is not possible to resolve issues related to perforation. So, it is not possible to minimize the negative cumulative effect and at the same time to form wide and deep perforations, or it is not possible to make perforations of the desired depth, etc. These issues could be resolved by cumulative perforation in the same perforation hole, when the cumulative stream would be directed to the previously created perforation hole during repeated perforation. However, none of the known technical solutions provides for repeated perforation with exposure to the same perforation holes that were formed in the first perforation cycle when the perforator was first lowered into the well. Even the equipment of one perforator with two types of charges such as cumulative and bullet does not solve this problem. Perforation with two types of perforation, such as bullet and cumulative perforation, does not allow perforation into the same perforations, because after the first impact of the type of bullet (or cumulative), an unsecured perforator is displaced in the well and a second impact of the type of cumulative (or bullet) is carried out with the perforator displaced and the cumulative jet does not enter the previously formed perforations.

The proposed invention solves the problem of combining the place of impact of perforation in the second and subsequent perforation cycles with the place of impact of perforation in the first cycle of perforation, changing the shape, expansion and deepening of perforations in the well, and reducing the negative impact on the annular cement stone.

The problem is solved in that in the method of perforating a well, including lowering the perforator into the well and perforating, according to the invention, after lowering the perforator into the well, it is fixed with the impossibility of rotation and displacement, perforation is performed in a fixed state, after perforation is lifted from the well, equipping charges and re-lowered into the well, after repeated descent, the perforator is fixed in the well in a position shifted azimuthally and / or vertically relative to the state, to Thoroe held drill after the first shutter holding re-perforation is performed in a fixed state after the re-perforating punch is raised from the well, if necessary, re-perforation operation is repeated.

In the method of perforating a well, the perforator is equipped with brine charges before different downs of the perforator.

In the method of perforating the well before the first descent into the well, the perforator is equipped with charges of lower power than the charges for equipping the perforator before the second descent.

In the method of perforating the well before the first descent into the well, the perforator is equipped with charges of greater power than the charges for equipping the perforator before the second descent.

SUMMARY OF THE INVENTION

During cumulative or bullet perforation of a well, a cement stone in the annulus experiences strong mechanical stress, leading to its destruction, delamination from the production string or rock, and cracking. According to the defects that have arisen, undesirable annular fluid flows appear, the water cut of the produced oil increases, and the isolation of the productive formations is violated. To avoid this, gentle cumulative perforation with weak charges is used, which has a relatively small effect on the annular cement stone. However, the number and depth of perforations is minimized, which adversely affects well productivity. Existing methods of cumulative perforation are not able to solve this problem. In the proposed invention, this problem is solved by combining the place of impact of cumulative perforation in the second and subsequent perforation cycles with the place of impact of perforation in the first perforation cycle. In this case, the combination is carried out with a shift up or down or in azimuth. With such perforation, a change in shape occurs, the perforation holes in the well expand and deepen, the negative impact on the annular cement stone is reduced, and the number of perforation holes decreases as their depth increases. The problem is solved as follows.

In the well in the interval of perforation, the lower part of the device for fixing (fixing) the casing punch is fixedly fixed. The upper part of the device for fixing (fixing) the perforator in the well is fixedly attached to the puncher. The device for fixing the perforator in the well is made in such a way that when in contact with the lower part, the upper part becomes stationary relative to the lower one, and consequently, the hammer also becomes stationary. In the first punching cycle, a case puncher is lowered into the well on a wireline cable with the upper part of the device for fixing the case punch until it contacts the lower part of the device for fixing the case punch. The perforator is equipped with cumulative charges. Perforate the well with a fixed (fixed) state of the perforator. Raise the punch from the well. Again equip the punch with cumulative charges. In the second punching cycle, a case perforator is lowered into the well on a wireline cable with the upper part of the device for fixing the case perforator until it contacts the lower part of the device for fixing the case perforator.

To change the shape of the perforation holes, repeated and / or subsequent perforation cycles are carried out with the cumulative effect shifted relative to the perforation holes made during the first descent of the perforator, forming a new form of the perforation hole or expanding the perforation hole, or even deepening it. So, when the axes of the perforation holes are displaced during subsequent cycles relative to the position in the first perforation cycle, the perforations can take a shape close to eight, ellipse, triangle, rectangle, polygon, straight line, curved line of almost any kind, the hole can be expanded in diameter. The hole may also be deepened.

Produce repeated perforation of the well. Raise the punch from the well. Stop punching or spend the third and subsequent cycles of punching the required number of times.

When perforating a well, perforators before different descents are equipped with charges of different capacities and / or charges forming perforation holes of different sizes in depth and cross section of the hole. The cumulative charges existing today can create, for example, wide but shallow perforations, or vice versa, deep but small diameters.

Before the first descent, the punch can be equipped with charges that form holes of large or small diameter, which is determined by the charges used to form holes of large or small diameter, and at the same time, of large or small depth, which is also determined by the charges used of greater or lesser power. Before the second and subsequent descents, the perforator can be equipped with the same charges or charges, differing in the formation of holes in diameter in a larger or smaller side or in the depth of the holes also in a larger or smaller side.

As charges forming holes of large diameter, can be used charges of the type ZPK-105 "N-BO". As charges forming holes of small diameter, charges of the ZPK-105 type can be used. As charges forming holes of great depth, charges of the ZPK-105DN type can be used. As charges forming holes of shallow depth, charges of the ZPK-105 type can be used.

To change the shape of the perforation holes, repeated and / or subsequent perforation cycles are carried out with a cumulative effect offset relative to the perforation holes made during the first descent of the perforator, forming a new form of the perforation hole or expanding the perforation hole. So, when the axes of the perforation holes are displaced in the first and subsequent perforation cycles, the perforation holes can take a shape close to eight, ellipse, triangle, rectangle, polygon, straight line, curved line of almost any kind, the hole can be expanded in diameter.

The second and subsequent perforation cycles can be performed without displacing the axes of the holes to deepen the perforations.

To solve various technical problems, the power of the cumulative effect is changed in different cycles of perforation.

To minimize the impact on the annular cement stone, a low-power cumulative effect in the first cycle and a more powerful effect in the second and subsequent cycles are used. Low-power charges in the first perforation cycle tend to break through the production casing, not caring for the depth of perforation, but maintaining the integrity of the cement stone. In the second and subsequent cycles, the perforations are deepened by powerful charges, without fear of destruction of the annular cement stone.

If you are not afraid of the destruction of the annular cement stone, then apply a powerful cumulative effect in the first cycle. At the same time, if the perforation of the hole with an undesirable zone (usually flooded) is feared, then a less powerful effect is used in the second and subsequent cycles.

A casing puncher can be lowered into the well on a tubing string with tight reference in depth and azimuthal orientation. To orient the bottom of the pipe string in the borehole in azimuth, a lot of methods and devices have been developed, such as gyroscopic orientation, orientation using gamma detectors, orientation using magnetic marks, mechanical devices, etc. In this case, there is no need for a device for fixing a casing punch in the well. However, in fairness, it should be noted the low accuracy of such orientation.

As a device for fixing a casing punch in the well, a variety of devices can be used. Examples of these include:

- setting on the packer the bottom of the device in the form of a crown with the location of the counterpart on the punch in the form of a reverse crown;

- setting in the interval of perforation of the pin (s) perpendicular to the axis of the well with the location of the counterpart on the perforator with slots for the pin (s);

- setting in the interval of perforation of the cone centralizer with an azimuth and mate orientation on the perforator in the form of an inverse cone, etc.

The lower part of the case punch has a threaded plug through which it is connected to the punch. The counterparts of the fixing devices are attached to this plug or to the punch body itself. It is possible that the counterpart is attached to the top cap. In this case, the punch after contacting the bottom of the fixing device will be suspended in the well.

The displacement of the punch in the second punching cycle relative to its position in the first punching cycle can be achieved by displacing the mating upper part of the device for fixing on the punch, changing the shape and size of the mating part, replacing the mating part with a new one with new dimensions.

Case Studies

Example 1 is a control. Perforate an oil well. The perforation interval is from 1610 to 1612 m. The well is cased with a production string with a diameter of 146 mm and a wall thickness of 8 mm. Before perforation, a cumulative-shaped case perforator is equipped with a device for fixing a perforator in a well, shown in FIGS. 1, 2 and 3.

The device comprises a bottom plug 1 of a perforator 2, a reciprocal part of a device for fixing a perforator 2 in a well 3 in the form of a cone-shaped guide tip 4 having round protrusions 5, a lower part of a device for fixing a perforator 2 in a well, which is a funnel 6 having grooves 7 round shape. A shank 8 having centralizers 9 is attached to the lower part of the device. The lower part of the device is located in the sump 10 of the well 3. A geophysical cable 11 is used to lower and remove the shank, as well as the perforator. The perforator 2 is also equipped with centralizers 12. The perforator 2 is placed in the productive interval formation 13. As a result of the work of the perforator, perforations 14 are formed.

The perforator is charged with cumulative charges of the ZPK-105DN brand, the perforator is collected and lowered into the well 3 on the geophysical cable 11 in the interval of the reservoir 13 until the upper part contacts the lower part of the device for fixing the perforator. Undermine the cumulative charges, resulting in the formation of perforations 14. The perforator is lifted from the well. The perforator is disassembled at the wellhead, recharged with cumulative charges of the ZPK-105DN brand, lowered into the well 3 on the geophysical cable 11 until the upper part contacts the lower part of the device for fixing the perforator. Undermine the cumulative charges. The hammer drill is lifted from the well. As a result, the depth of the perforations increased from 650 to 1000 mm. The shape of the holes remained unchanged as after the first cycle of perforation.

Example 2. Perform as example 1. Disconnect the plug 1 and the cone-shaped guide tip 4, weld a 2 mm thick ring onto the plug and cone-shaped guide tip 4 is welded to the ring. Next, the perforation is performed as in example 1. As a result, perforated holes of an elongated shape are obtained.

Example 3. Perform as example 1. Disconnect the plug 1 and the cone-shaped guide tip 4 and again weld the cone-shaped guide tip 4 to the plug 1 by turning 1 degree. Next, the perforation is performed as in example 1. As a result, perforation holes of a horizontally elongated shape are obtained.

As a result of perforation according to examples 1-3, the flow rate of the well compared with the surrounding oil producing wells with conventional one-time perforation with the same amount of the same charges increased by 35% and amounted to 8 m ³ / day.

Annular fluid flows are not observed.

Example 4. Perform as example 2. For perforation at the first descent of the punch, non-deep-penetrating cumulative charges of the ZPK-105 "N-BO" grade are used, which are capable of piercing the production casing and forming perforation holes of small depth, but large size. During repeated perforation, cumulative charges of the ZPK-105 “DN” brand are used, capable of forming deep perforations in the annular space.

Studies have shown that the cement stone in the annulus of the well has been completely preserved, there are no cracks and delaminations from the rock and production casing. Cross-flowing flows are not observed. Well production compared to surrounding wells increased by 22%.

Example 5. Perform as example 3. A well was opened by a well that, due to technical reasons or design features of a particular well, was blocked by two columns. Cement stone in the annular space is either absent or has pronounced defects in the form of poor adhesion and breaks. It is planned to carry out perforation, and then perform repair and insulation work by pumping cement mortar into the annulus.

For the perforation during the first descent of the perforator, powerful cumulative charges of the ZPK-105 “DN” brand are used, capable of not only punching the production casing, but also forming perforation holes of increased depth. With repeated perforation, the same cumulative charges are used. As a result, a message was received with annular space and cementing was performed to eliminate annular overflow.

Thus, the application of the proposed method will allow us to solve the problem of combining the place of impact of cumulative perforation in the second and subsequent perforation cycles with the place of impact of perforation in the first perforation cycle with a change in the shape, expansion and deepening of the perforation holes in the well, the task of reducing the negative impact on the annular cement stone upon reaching wellbore communication with annulus.

The application of the proposed method will allow you to combine the impact of cumulative perforation in the second and subsequent perforation cycles with the impact of perforation in the first perforation cycle, change the shape, expand and deepen the perforation holes in the well, reduce the negative impact on the annular cement stone when the wellbore communicates with the annulus .

Claims (3)

1. The method of perforation of the well, including the descent of the perforator into the well and perforation, characterized in that after the descent of the perforator into the well, it is fixed with the impossibility of rotation and displacement, the perforation is carried out in a fixed state, after the perforation is carried out, the perforator is raised from the well, charged with charges and re-lowered into the well, after repeated descent, the perforator is fixed in the well in a position shifted azimuthally and / or vertically relative to the state occupied by the perforator after the first descent, repeated perforation is performed in a fixed state, after repeated perforation, the perforator is lifted from the well, if necessary, repeated perforation operations are repeated. 2. The method according to claim 1, characterized in that the perforator is equipped with charges of the same or different power before different descents of the perforator. 3. The method according to claim 1, characterized in that when the perforation of the well before the first descent into the well, the perforator is equipped with charges of lower or greater power than the charges for equipping the perforator before the second descent.

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