RU2582353C1 - Method for gas-dynamic action on formation - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to oil production technologies and can be used for gas-dynamic action on formation. Method involves cumulative perforation well interval with formation in well casing string and in mine rock of grouped perforation channels for fluid inflow, subsequent operation of pressure generators and their impact on formation through grouped perforation channels for fluid inflow to form in mine rock of rock individual fractures in direction of each perforation channel. At that, adjacent perforation channels in group are directed in opposite directions. Linear distance between perforation channels in group is different or equal to linear distance between groups of perforation channels.

EFFECT: technical result consists in improvement of efficiency of gas-dynamic action on formation.

6 cl, 4 dwg, 2 ex

Description

The invention relates to the oil and gas industry, and in particular to means for oil production. It ensures the creation of cracks and cavities in the near-wellbore zone of the treated formation, which provide reliable hydrodynamic communication with the remote oil-saturated zone of the formation, which has natural filtration properties.

There is a known method of gas-hydraulic stimulation of a formation, including deep-perforating perforations at all intervals of the processed formation, formation of perforation channels in the casing of the well and in the rock for fluid inflow, followed by gas-dynamic impact on the formation and real-time monitoring of the combustion of charge sections (patent RU No. 2183741, IPC E21B 43/263, publ. 06/20/2002).

In this method, the use of real-time monitoring of the combustion process will probably prevent an emergency violation of the integrity of the casing string in the processed interval of the well and break the formation, providing a hydrodynamic connection with its remote zone, but it is impossible to call this connection reliable precisely with the oil-saturated zone of the formation for the inevitable destruction of the cement ring behind the pipe string already during perforation and with further rupture, as well as due to the formation of a single crack destruction of the furnace oh breed at break. This method provides reliable hydrodynamic communication with a water-saturated remote zone of the reservoir, and not with oil. The effectiveness of the location of punched perforation channels is not considered, however, traditional methods of gas-dynamic impact involve exposure to the formation through perforation channels for fluid inflow, located in a line or spiral, without dividing the channels into groups, which leads to a decrease in the efficiency of gas-dynamic treatment of the formation due to violation of the integrity of the cement rings behind the column of pipes. Subsequent gas-dynamic impact on the formation breaks up the partitions in the cement ring between the perforation channels, man-made cracks join, forming the line of least resistance to fluid flow in the cement ring of the well, which leads to its early flooding. And in the rock when it breaks, a single crack of rock destruction is formed. Water flooding along it is even faster than along the line of least resistance to fluid flow in the cement ring.

There is a method of opening a reservoir by cumulative charges, which are grouped in a cumulative perforator in the form of pairs, while the channels forming a pair are located relative to each other at the same angle, and the angle between the pairs of channels is different from the angle in pairs or equal to it (patent RU No. 2370639 IPC E21B 43/117, published on October 20, 2009).

There is a method of opening a reservoir by cumulative charges arranged in groups, with the charges forming the groups located relative to each other at a certain angle in different planes, and the angle between the groups of charges is determined depending on the angle in the group of charges, and these groups of charges are located in different planes (Patent RU No. 2447267, IPC E21B 43/117, publ. 07.20.2011).

The disadvantages of these inventions (RU No. 2370639, RU No. 2447267) is the absence of rock fracture and increased fracture beyond the perforation radius, the lack of reliable hydrodynamic communication with the remote formation zone.

To ensure effective rock fracture and prevent the destruction of the cement ring behind the pipe string, the perforation channels in the group formed during cumulative perforation should be directed in opposite directions. In this case, depending on the geological conditions, it is possible to change the linear pitch between the perforation channels in the group and between the groups of perforation channels.

The task to which the claimed technical solution is directed is to develop a method of gas-dynamic impact on the formation, which provides: reliable hydrodynamic communication with the borehole and the remote oil-saturated zone of the formation, reducing the rate of water cut in the well and maintaining the integrity of the cement ring behind the pipe string.

The technical result of the invention is to prevent the creation of a single fracture rock fracture in the treated interval during gas-dynamic impact on the reservoir and the increase in the volume of the filtration system of cracks in the reservoir.

The required technical result is achieved by the fact that in the method of gas-dynamic stimulation of the formation, including cumulative perforation of the well interval, formation of perforation channels in the casing of the well and in the rock for fluid flow, subsequent operation of pressure generators and their effect on the formation, the feature is that pressure generators act on the formation through grouped perforation channels for fluid inflow with the formation of individual rock fractures in the rock th rock in the direction of each perforation channel, and adjacent perforation channels in the group are directed in opposite directions, and the linear distance between the perforation channels in the group is different or equal to the linear distance between the groups of perforation channels.

In addition, before gas-dynamic impact on the formation, several perforations of the treated interval of the well are produced, and the perforation channels for fluid inflow formed by each subsequent perforation are deviated from the perforation channels formed by the previous perforation.

Traditional methods of gas-dynamic impact involve exposure to the formation through perforation channels for fluid inflow, located in a line or spirally along the interval of the well, without dividing the channels into groups, which leads to a decrease in the efficiency of gas-dynamic treatment of the formation due to the violation of the integrity of the cement ring behind the pipe string during perforation. Subsequent gas-dynamic impact on the formation breaks up the partitions in the cement ring between the perforation channels, man-made cracks join, forming the line of least resistance to fluid flow 4 in the cement ring of the well, which leads to its early flooding. And in the rock when it breaks, a single crack 5 of rock destruction is formed. Water flooding along it is even faster than along the line of least resistance to fluid flow in the cement ring.

The proposed method allows for gas-dynamic impact with fracturing, without violating the integrity of the casing and cement stone without forming the line of least resistance to fluid flow 4. During the gas-dynamic impact, the formation of individual cracks 6 in the rock of a rock fracture in the direction of each perforation channel is achieved by grouping perforation channels in the reservoir, and the perforation channels in the group formed during cumulative perforation must It is directed in opposite directions. If the adjacent perforation channels are directed in the same direction or close, then when the gas-dynamic effect is applied, it is impossible to obtain individual fracture cracks in the rock in the direction of each perforation channel.

Depending on the geological and geological conditions, a change in the linear pitch between the perforation channels in the group and between the groups of perforation channels is assumed, which also reduces the probability of violating the integrity of the casing and cement stone. So, for example, by reducing the linear step between the perforation channels in the group and increasing it between the groups, it is possible to achieve the claimed effect in wells with a weak cement ring or to increase the number of perforation channels in the interval.

An increase in the volume of the filtration system of cracks in the formation is achieved by the formation of individual cracks 6 of rock fracture in the direction of each perforation channel and, accordingly, by the grouping of perforation channels 2 in the formation. The total volume of individual cracks 6 of rock fracture of all channels of the proposed method is greater than the volume of a single rock 5 of fracture of rock obtained by traditional methods of gas-dynamic processing, since the perforation channels in the group are directed in opposite directions, and the offset of the channel groups relative to each other by a certain angle increases formation coverage.

Depending on the geological conditions, the interval of the well revealed by cumulative perforation may consist of one or more intervals of the treated formation, one or more layers and interlayers, moreover, they are opened simultaneously or separately, the whole or part of it is opened.

Delivery of perforators and pressure generators in the impact interval is carried out by all known delivery methods - on tubing, tubing, flexible pipes, on a geophysical cable depending on geological conditions. But to increase the efficiency of the method, the preferred option is the delivery on a universal geophysical cable, since the volume of construction of sidetracks in vertical wells and the volume of construction of horizontal wells are increasing. A universal cable is capable of delivering devices to both vertical and horizontal sections of the well.

To increase the efficiency of the method, a gas-dynamic effect on the rock through grouped perforation channels of different sizes is possible, when the sizes of the perforation channels in one group of channels are different from the sizes of the channels in the subsequent group, and the groups can alternate. For this, cumulative charges with various breakdown characteristics are used. In the overlying group, “large hole” charges are used, in the underlying group, “deep penetration” charges are used, the groups can alternate.

A group of perforation channels should be understood as two, three or more channels, and by the direction of the perforation channels in opposite directions is the angle of one channel relative to the other by 180 ° ± 45 °. In the figures, this angle is indicated by α.

Grouping parameters: total number of perforation channels, number of channels in a group, location (angles, direction, linear step) in a group and between groups, density, channel diameter and length, etc. appoint depending on the conditions of intensification of the influx by the method of gas-dynamic effects on the reservoir.

The perforation radius is the length of the perforation channel in the rock before any impact on the formation through it.

The invention is illustrated by drawings, in which:

in FIG. 1 (a) schematically shows the traditional arrangement of perforations in a casing in a spiral, where:

1 - perforated interval of the well with a cement ring,

2 - perforation channels

3 - technogenic cracks in the cement ring,

4 - line of least resistance to fluid flow in the cement ring of the well;

in FIG. 1 (b) schematically shows the location of the grouped perforation channels 2 in the casing: α is the angle in the group of perforation channels 2, β is the angle between the groups of perforation channels, C is the linear step in the group of perforation channels, D is the linear step between the groups of perforation channels;

in FIG. 2 (a) shows the formation of a single crack 5 of rock destruction with known methods of gas-dynamic impact;

in FIG. 2 (b) shows the formation of cracks in the rock with the claimed technical solution, when each perforation channel 2 has an individual rock fracture 6;

in FIG. 3 shows a scan of the bottomhole formation zone with perforation channels 2 for fluid inflow obtained with one perforation;

in FIG. 4 shows a scan of the bottom-hole zone of the formation with perforation channels 2 for fluid inflow obtained with two perforations; the channels obtained during the second perforation are shaded;

in FIG. 3 and FIG. 4 vertical grid lines correspond to the azimuthal angles of perforation channels, and horizontal grid lines to serial numbers of perforation channels; further in FIG. 4 shows the angle of displacement of the channels of the first perforation from the channels obtained by the second perforation interval of 90 °.

The method is carried out in the following sequence.

Depending on the conditions of stimulation of the influx by the method of gas-dynamic stimulation of the formation, the parameters of the grouping of perforation channels 2 in the well interval are determined. The total number of perforation channels in the interval is determined, the number of channels in the group and the number of groups are determined, the angle in the group of perforation channels α, the angle between groups of perforation channels β, the linear step in the group of perforation channels C, the linear step between groups of perforation channels D, and the perforation channels in the group should be directed in opposite directions, that is, the angle α is assigned in the range of 180 ° ± 45 °, and the angle between the groups of perforation channels β can have any value depending on the conditions applications, determine the density, diameter and length of the channel. Spend the equipment and lower the cumulative punch (or several punch) in the machined perforated interval 1 well (or at several intervals), produce its shooting. In the casing of the well and in the rock, grouped perforation channels 2 are formed for fluid flow, after which the perforator is lifted to the surface. Next, pressure generators are lowered into the perforated interval 1 of the well (or intervals), they are initiated, pressure generators act on the formation through grouped perforation channels 2 for fluid flow. In the rock, in the direction of each perforation channel 2, individual cracks 6 of rock rupture are formed, propagating along the perforation channel 2 over the radius of perforation. The equipment is removed from the well, the well is switched to mode.

The descent of perforators with generators can be combined, in this case all the equipment used is removed from the well after the pressure generators are triggered.

Case Studies

Example 1

Mining and geological conditions are known under which a gas-dynamic effect on the reservoir will be produced. The parameters for grouping perforation channels 2 in the perforated interval 1 are established: the length of the interval is 3 meters, the required number of perforation channels is 30, the density of the perforation channels is 10 channels per 1 meter of the interval, the number of perforation channels in the group is 2 channels, the number of groups is 15, the perforation channels in the group are multidirectional at an angle (α) of 180 °, the angle between the channel groups (β) is 135 °, the linear step between the channels in the group (C) is 50 mm, the linear step between the channel groups (D) is 200 mm, the diameter of the channel is 18 mm.

Equipment and descent of a cumulative perforator that meets the grouping parameters in the perforated interval 1 of the well is carried out, it is shot with the formation of grouped perforation channels 2 in the casing of the well and in the rock, then it is lifted. The pressure generators are lowered into the perforated interval, they are initiated, the pressure generators act on the formation through the grouped perforation channels 2 for the flow of fluid. In the rock, individual rupture cracks 6 are formed in the direction of each perforation channel 2, propagating along the perforation channel 2 beyond the perforation radius. The equipment is removed from the well, the well is switched to mode.

Example 2

Mining and geological conditions are known under which a gas-dynamic effect on the reservoir will be produced. The parameters for grouping perforation channels 2 in the perforated interval 1 are established: the length of the interval is 3 meters, the required number is 60 channels, the density of the perforation channels is 10 channels per 1 meter of the interval, the number of channels in the group is 2 channels, the number of groups is 30, channels in the group are multidirectional at an angle (α) of 180 °, the angle between the groups of channels (β) is 135 °, the linear step between the channels in the group (C) is 50 mm, the linear step between the groups of channels (D) is 200 mm, the diameter of the channel is 18 mm

To obtain the required number of perforation channels 2 in the perforated interval 1, it is necessary to produce two perforations of one perforated interval 1.

The first cumulative perforator is equipped with an orienting device attached, the perforator is lowered into the perforated interval 1 and it is shot to form the first row of grouped perforation channels 2 in the well casing and in the rock, then it is lifted. The second perforator is equipped with an orienting device attached to it, the perforator is lowered into the perforated interval 1 and it is shot to form a second row of grouped perforation channels 2 in the casing of the well and in the rock, which are deviated from the first row of grouped perforation channels, then the perforator is lifted . The pressure generators are lowered into the perforated interval 1, they are initiated, the pressure generators act on the formation through the grouped perforation channels 2 for the flow of fluid. In the rock, individual cracks 6 of rock fracture are formed in the direction of each perforation channel 2. The equipment is removed from the well, the well is switched to the mode.

The application of the proposed method allows to maintain the integrity of the casing and cement ring between the perforation channels by grouping the perforation channels, as a result of which the formation of the line of least resistance to fluid flow in the cement ring is prevented, which leads to early flooding of the well. In addition, grouped perforation channels increase the efficiency of gas-dynamic impact by increasing the feed zone of each perforation channel, which occurs when the perforation channels are multidirectional in the group, increase the fracturing and the volume of impact on the formation, because each perforation channel will have an individual rock fracture crack, thereby preventing the creation of a single rock fracture crack, increasing the well watering rate. In addition, in the treated interval of the well increases the flow of fluid due to additional perforation. Possible additional impact on the reservoir while lowering the flow rate of the well, because the cement ring will be preserved and each perforation channel will have an individual rock fracture crack. The proposed method makes it possible to have a multi-stage impact on the formation when, after the formation of the grouped perforation channels, the pressure is repeatedly applied by the pressure generators to the formation with an increase in the size of individual fractures in the rock during each subsequent impact in order to increase the inflow.

Claims (6)

1. The method of gas-dynamic impact on the formation, including cumulative perforation of the well interval, the formation in the casing of the well and in the rock perforation channels for fluid flow, the subsequent operation of pressure generators and their impact on the reservoir, characterized in that the perforation channels for fluid flow are grouped, and pressure generators act on the formation through the formed grouped perforation channels for fluid flow with the formation of individual fracture fractures in the rock molecular rocks in the direction of each perforation, the perforations adjacent channels in a group are directed in opposite directions, and the distance between the perforations in the band is great or equal to the linear distance between the groups of perforations. 2. The method according to claim 1, characterized in that before the gasdynamic impact on the formation, a series of perforations of the interval are produced, and the grouped perforation channels for fluid flow formed by each subsequent perforation are deviated from the grouped perforation channels formed by the previous perforation of the interval. 3. The method according to claim 1, characterized in that the grouped perforation channels are formed in a group with dimensions different from the sizes of the grouped perforation channels in a subsequent group, while the groups can alternate. 4. The method according to claim 1, characterized in that the delivery of cumulative perforators and pressure generators in the interval of exposure is carried out on a universal geophysical cable. 5. The method according to claim 1, characterized in that the delivery of cumulative perforators and pressure generators in the interval is performed simultaneously. 6. The method according to claim 1, characterized in that the size of the individual fractures of the rock rupture in the direction of each perforation channel is increased by repeated exposure to the formation of pressure generators.

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