RU2471973C2 - Device operating on solid fuel and used for well treatment, and its application method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: device includes cylindrical powder tubular charges, including ignition ones, with different diameters of channels and ratio of lengths of charge channels to diameters of channels of (20-40):1, and load-carrying rope with structure fixing elements. According to the invention, device also includes cylindrical powder tubular charges of smaller diameters, which have ratios of lengths of charge channels to diameters of channels of (6-80):1 and ratio of outer diameters of charges of smaller and larger diameter of (0.6-0.95):1. At that, charges of different diameters are alternated. Besides, charges with smaller diameters and ratios of lengths of channels to diameters of channels of (40-80):1 are provided with external annular grooves and through channels in places of grooves. Charges of larger diameter have shells to be protected against friction in the well. On edges of alternating charges there fixed are discs with annular projections entering each other at assembly of charges.

EFFECT: increasing production efficiency of hydrocarbons; enlarging the application scope of the device; improving its reliability for wells, including at increased temperatures and pressures.

2 cl, 1 ex, 1 dwg

Description

The invention relates to the oil and gas industry, and in particular to devices (powder generators) designed for treating the bottom-hole formation zone (PZP) with high-temperature gases released during the combustion of solid fuel cells (TFE). In most cases, ballistic gunpowder is used as a TFE.

Generators (another name for gas generators) are used to increase hydrocarbon production in wells contaminated with asphalt tar and paraffin deposits, as well as after poorly performed perforation. The TFE of the generators is fastened into one garland with special equipment, lowered on the cable to the interval of processing the reservoir, ignited by the current supply through the cable and by burning.

A device is known for impacting a formation by pressure of solid fuel combustion products [1]. Its unarmored TFEs with a high initial combustion surface and a small thickness of the burning roof have slots in the TFE or multi-tube block elements made of mixed fuel.

Known generator with a detonation system for initiating tubular TFE [2]. TFEs are coated on the side surface and a thin-walled metal tube in the central channel. A detonating cord connected to a sealed explosive cartridge is laid along the entire length of the tube.

A device [3] is known with one or more groups of igniter fuel cells. Above them or between them there is a TFE with a thick-walled metal tube in the channel.

A known method of processing the bottomhole formation zone and a device for its implementation [4]. The method sets the characteristics of the pressure pulses when creating excess pressure in the well from the combustion of the fuel cell. The device contains powder elements mounted on support tubes with a complex ignition system in them.

Known open-section sectional charge for gas-dynamic impact on the reservoir [5]. This device includes an ignition unit, powder sections and accessories from parts for their collection. Equipment passes through the central channel of each powder section and has parts for tightening powder sections close to each other.

All of the listed devices have bulky equipment running along the TFE axis, as well as a complex ignition system. After the combustion of the thermoelectric fuel cell, part of the equipment remains in the well. An additional disadvantage of the device [5], in addition to complexity and a large mass of equipment, is a relatively small mass of fuel.

Known gas generator with an adjustable pressure pulse for wells, having a tubular armored TTE and a load-bearing geophysical cable with fasteners [6].

The number of unarmored and armored tubular fuel cells is determined by the formulas taking into account the characteristics of fuels and wells.

During the combustion of the solid fuel cells, pressure pulsations occur against the background of a general increase in pressure in the well. Pulsations additionally contribute to an increase in the efficiency of thermogasochemical treatment of PZP due to the destruction of the walls of cracks and colmatants with alternating loads. The duration of the combustion of TFE varies from several hundredths to several tenths of a second.

The disadvantage of a gas generator [6] is the complexity of its layout as a whole. The presence of armored fuel cells in this device leads to additional contamination of the well after their combustion. The selection of the required number of armored and unarmored charges, providing the best effect, is very doubtful.

A known method of thermogasochemical effects on the reservoir and solid fuel charge for its implementation [7]. Despite the abundance of claims, the following is clear. The method is carried out by a device containing channel and non-channel TFEs, which are located in a hollow housing with an igniter. The lower end of the housing is muffled, and the upper is equipped with a regulator of the flow of powder gases. Thus, the device resembles a rocket engine with a pulsating outflow of combustion products through a nozzle.

Due to the complexity of the device, it will not work and, moreover, will not be effective under many geological and technical conditions of the well. For example, solid-state fuel cells in the hollow housing, burning from the end, will spontaneously attenuate, as is the case in rocket engines with increased heat loss. Great pressure in the well cannot be reached. Pressure pulsations without a general increase in pressure in the well will not bring the expected effect. There is no reliable evidence that the pressure pulsation frequencies created by the device are most suitable for increasing oil production, no.

For the manufacture of generators, some channel thermopiles, previously used in rocketry and intended for disposal, may be suitable. An insignificant refinement of such thermoelectric fuel cells will allow mass production of cheap, simple and efficient generators for a wide variety of geological and technical conditions. There are many difficulties. One of them is to make generators with utilized converted charges function reliably at high pressure and temperature.

For new generators with TFEs of various shapes and sizes, a simple universal tooling with a minimum number of parts and a reliable ignition system are needed. This is not the case with the considered analogues.

A gas generator with cylindrical powder tube charges, including igniter or igniter, and a load-carrying cable with structural fasteners for thermogaschemical and vibration microwave treatment of the formation is a prototype [8]. Its TFE creates overpressure in the well. TFEs have different diameters of the central circular channels, and the ratio of channel lengths to the diameters of these channels is (20-40): 1. Between the charges or in the charges themselves, there are passages for connecting the cavity of the TFE channel with the outer surface. The content of the filler stabilizer of combustion in the fuel mass is not more than 1.5%.

The disadvantages of the device and method of its implementation are as follows. This device does not have a TFE of various external diameters with other ratios of channel lengths to their diameters, as well as with a stabilizer content in the fuel of more than 1.5%. This limits the design and operational capabilities of the device and the use of recycled fuel cells of different sizes and from a larger number of fuels.

In addition, at elevated temperature, pressure, and an increase in the ratio of the TFE channel length to its diameter, there is a danger of a charge rupture from the channel side, since gases do not have time to leave the channel. Similar regimes of combustion of a solid fuel cell with a narrow channel were considered and investigated in [9]. The data experimentally obtained in this work were used in the analysis of the operability of the designed generators.

For the expulsion of powder gases through the end sections of the TFE, a certain pressure drop relative to the surrounding medium element arises inside its channel. This difference depends on the stress-strain state of the TFE and is determined by its geometric dimensions.

The strength performance of a channel solid-fuel cell made from ballistic powder or mixed solid fuel located in the well is ensured when the condition

ε _about β≤ε _b ,

where ε _about - circumferential deformations that occur on the channel of the TFE (%),

ε _about - the ultimate strain of the thermoelectric fuel (%),

β is the safety factor (β = 2).

The circumferential deformations on the TFE channel are determined by the formula

where E, µ is the elastic modulus and Poisson's ratio for the charge,

r _about - the radius of the channel of the TFE,

r _N is the outer radius of the TFE,

p _ST is the static pressure in the well corresponding to the depth of immersion and acting on the outer lateral surface of the thermoelectric fuel,

p _ok - pressure inside the channel of the TFE (determined by the ratio of the length of the charge to the diameter of the channel),

p _OT - static pressure at the ends of the TFE (p _OT = p _CT ). As the temperature rises to + 90 ° C (the maximum for the use of TFE in the well), the elastic modulus for ballistic gunpowder decreases tens of times compared with the initial temperature + 20 ° C. At + 90 ° C, circumferential deformations, for example, when the ratio of the length of the TFE channel to its diameter 40: 1 and the outer diameter of the charge is 100 mm, increase several times with a well depth of more than three kilometers.

Obviously, appropriate measures should be taken to increase the efficiency of the thermoelectric fuel cells with long charges and a narrow channel.

The objective of the invention is to develop a universal and simpler when assembling a device for solid fuel to increase hydrocarbon production in the well, to expand the geometric parameters of charges and brand of fuels, allowing you to select ready-made disposed fuel cells (without preparing the fuel mass). Another task is to expand the applicability of a device with different thermal characteristics, as well as to increase its reliability, including at elevated temperatures and pressures.

To solve the problem in a known device for solid fuel for treating wells, including cylindrical powder tube charges, including igniter or igniter, with different diameters of the channels and the ratio of the lengths of the channels of the charges to the diameters of these channels (20-40): 1, and load-bearing the cable with the fastening elements of the structure according to the invention is new, that the device further includes cylindrical powder tube charges of smaller diameters, which have channel length ratios the diameters of the channels (6-80): 1 and the ratio of the outer diameters of the charges of a smaller and larger diameter (0.6-0.95): 1, while the charges of different diameters alternate, in addition, for charges with smaller diameters and ratios of the lengths of the channels to the diameters of the channels (40-80): 1 there are external annular grooves and through channels at the place of the grooves, and the charges of a larger diameter have clips to protect them from friction in the borehole, while at the ends of alternating charges disks with annular protrusions entering each other are fixed when assembling charges.

The problem is also solved by the fact that in the known method of treating the bottom-hole zone of the formation using a solid fuel device, which includes creating excess pressure in the well by exposing the formation to the formation of gaseous combustion products of cylindrical powder tube charges with different channel diameters and the ratio of the length of the charge channels to the indicated diameters ( 20-40): 1, new is that overpressure in the well is created by the action of additional cylindrical gunpowder on the formation of gaseous products of combustion tubular charges of smaller diameters, alternating with charges of a larger diameter, while charges of a smaller diameter have a ratio of channel lengths to channel diameters (6-80): 1 and the ratio of the outer diameters of charges of a smaller and larger diameter (0.6-0.95); 1, and at temperatures of + 60-90 ° C and pressures of 20-40 megapascals in the well, eliminating charge discontinuities with ratios of channel lengths to channel diameters (40-80): 1 per set of fragments with an abnormal increase in pressure due to a critical increase in pressure drop in the axial channels of the burning charges rel Regarding the environment, they are achieved by dividing these charges into two separate fragments at the place of the annular grooves when the combustion fronts meet from the outer surfaces of the charges and from their channels.

The device and method are implemented as follows.

Figure 1 shows the device is a generator with a cylindrical powder tube tubular fuel cell. It has a load-carrying cable 1 along the axes of the charge channels 2 and 3 of different sizes. These TFEs have discs 4 and 5 of different diameters fixed at the ends with end protrusions entering into each other. At the ends of the charges 2 there are holders 6, which protect them from friction with subsequent spontaneous ignition in the well. The top charge 2 in the assembled garland is igniter. A heating element (for example, an incandescent wire) is mounted in it.

Discs 4 and 5 with other accessories - a cover at the top, a pallet at the bottom and their mountings to the cable provide the rigidity of the generator as a whole.

Charge 2 has a diameter of 100 mm and a length of 600 mm, which corresponds to the length of the channel. The ratio of the length of the channel to its diameter, equal to 20 mm, is 30: 1. The diameter of 100 mm is the maximum for wells with an internal diameter of 124-127 mm (column 146 mm). A further increase in this diameter in the presence of safety clips (protective shells) of a thickness of 2-3 mm due to the narrow gap between the charge and the inner surface of the column will lead to difficult passage of the thermoelectric fuse.

Charge 3 has a diameter of 60 mm and a length of 84 mm, which corresponds to the length of the channel. The ratio of the length of the channel to its diameter (14 mm) is 6: 1. The ratio of the outer diameters of the charges 3 and 2 is 0.6: 1. Charges 2 and 3 alternate with each other.

The ratio of smaller and larger diameters of charges of 0.6: 1 is the minimum for this design of the generator. This is explained by the following. Firstly, a further decrease in this ratio reduces the efficiency of the generator due to the loss of fuel mass per unit length of the generator. It is necessary to increase the length of the cable 1 for additional charges. Secondly, the connection of disks (centralizers) 4 and 5 of charges 2 and 3 due to the presence of charge channels and the small outer diameter of charge channel 3 is limited in size. This connection will not be reliable.

The ratio of the length of the charge channel 3 to its diameter (6: 1) is also the smallest for the above reasons. Assembling a generator with such short charges is cumbersome. We need additional components of the generator.

The outer diameter of the charge 3 can only be increased from 60 mm to 95 mm. Further, it is impossible to increase the outer diameter of the charge 3, because clips like charge 2 will be required. Thus, the ratio of the diameters of charges 3 and 2 of 0.95: 1 is the maximum.

To increase the efficiency of the generator shown in figure 1, the additional charge 3 must have the largest geometric dimensions (diameter, length) with a minimum diameter of the channel. At the same time, it should not be torn during combustion from excessive gas pressure from the channel. Therefore, the minimum channel diameter cannot be less than 14 mm. Cable 1 will not pass into a narrower channel. It is also necessary to take into account the mandatory presence of an annular gap between the cable and the inner surface of the TFE channel for the passage of gaseous products of combustion.

The maximum charge length 3, ensuring its operability at a temperature of + 60-90 ° C and a pressure of 20-40 megapascals in the well with a minimum channel diameter of 14 mm, should be 560 mm. The ratio of the length of the channel to its diameter in this case is 40: 1. The safe ratio of the outer diameters of the charge 3 and 2 is (0.6-0.95): 1. The larger the diameter of the TFE at a fixed charge length, the safer its operation.

The maximum lengthening of the charge 3 will be with the ratio of the channel length to its minimum diameter of 80: 1. The charge length in this case will be 1120 mm. With a greater length and diameter of the charge 60-95 mm, it will bend with increasing temperature. In addition, TFEs of small diameter with a large length are difficult to dock with each other during assembly. When the ratio of the length of the TFE channel to its diameter (40-80): 1 there is a danger of it breaking in the combustion process into several fragments from the combustion products bursting from the channel. Therefore, a constructive method for bridging the gap is proposed.

Figure 2 shows a variant of the device with the same symbols as shown in figure 1. The differences are only in the size and configuration of the charge 3. In the center, the charge shown in figure 2 has an outer annular groove and a through channel crossing it. The ratio of its channel length to the channel diameter of 14 mm is (40-80): 1, i.e. TTE length varies from 560 mm to 1120 mm. It is the annular groove and the through channel through it that protect the fuel cell from bursting during combustion associated with a critical excess of pressure in the channel over external pressure.

Without a groove, in a TFE with a long length, it is destroyed due to the gases bursting from the inside into many separate fragments with an anomalous explosion of pressure from volumetric combustion. The division of the charge along the groove does not lead to this. TFE is divided into only two separate fragments. Due to the appearance of new end surfaces of fragments with a small area, the pressure in the well almost does not increase. The through channel improves the conditions of charge ignition 3, because promotes the movement of burning gases from the igniter charge 2.

The assembly of the device (figure 1 and figure 2) with the help of a load-carrying cable 1 occurs at the wellhead. Charges 2 and 3 are alternately docked through disks 4 and 5. The device is lowered into a predetermined interval on a geophysical cable. In this case, the clips 6 protect the charges 2 from friction, and the charges 3 do not touch the inner surface of the well. After installing the device in the right place through the cable and connected to the heating elements of the igniter charge 2 electric wires are supplied with alternating current 220 volts. Ultimately, after the ignition of charges 2, combustion extends to all the fuel cells. Well treatment is in progress.

An example implementation of the method according to the device shown in figure 1.

In a well with an internal diameter of 127 mm, the oil reservoir is at a depth of 2.9 km. The length of the perforation interval is 5 meters. Well temperature + 80 ° C. The conditions in the borehole should be normal for the combustion of solid fuel cells from ballistic gunpowder with a ratio of the length of the charge channel 3 to its diameter in the range (6-40): 1.

Charge 2 with a diameter of 100 mm was selected. The length of the TFE channel is 895 mm, the diameter is 24 mm, and their ratio is 37.3: 1. Charge 3 without a groove and a through hole through it has a diameter of 70 mm. The length of the channel is 500 mm, the diameter of the channel is 17 mm, their ratio is 29.4: 1. It falls within the limit (6-40): 1. The diameters of the charges 3 and 2 are 0.7: 1.

The method is implemented by a device (generator) assembled from five charges 2 and four charges 3. As a result of processing, additional inflows without charge discontinuities were obtained. Well pressure is 69 MPa.

An example implementation of the method according to the device shown in figure 2.

In a well with an internal diameter of 127 mm, the oil reservoir is at a depth of 3.2 km. The length of the perforation interval is 4 meters. The temperature in the well is + 85 ° C. Thus, the conditions in the well are close to extreme for the ballistic gunpowder from which charges 2 and 3 are made. With a ratio of the length of the charge channel 3 to its diameter (40-80): 1 and the absence of a groove, it can burst during combustion. Therefore, grooving is necessary.

Use charge 2 with a diameter of 104 mm. The length of the TFE channel is 895 mm, the channel diameter is 24 mm, their ratio is 37.3: 1. Charge 3 has a diameter of 93 mm. The channel length of this TFE is 900 mm, diameter 14 mm, their ratio is 64.3: 1, which falls within the limit (40-80): 1. An annular groove made for charge 3 has a width of 3 mm and a depth of 10 mm. There is also a through hole at the groove. The ratio of the diameters of the charges 3 and 2 is 0.89.

The method is implemented by a device assembled from three charges 2 and two charges 3.

After ignition, charges 2 and 3 burn normally on all surfaces. Burning along the groove also occurs. It expands and deepens. The strength performance of charge 3 with an increase in overpressure in its channel as the total pressure rises and against the background of charge 3 heated to a high temperature, sharply decreases.

At a pressure of 45 MPa, a narrow bridge between the groove and the channel does not withstand. Charges 3 burst along the grooves. New fragments with a half-length reduced begin to burn autonomously safely. Their volumetric destruction from the channels, followed by an abnormally high pressure in the well, which would have been with a TFE without a groove, was prevented.

Well treatment allows you to get additional inflows with forced division of charges 3. The maximum pressure during processing is 82 MPa.

The considered options for using the device and method for processing wells are acceptable under various geological and technical conditions, including extreme ones.

Information sources

1. USSR author's certificate No. 1704513 A1, 5 cl. E21B 43/263. A device for impacting a formation by pressure of solid fuel combustion products. Sukhorukov G.I., Belyaev B.M. et al. 05/03/1988. Registered on 09/08/1991.

2. RF patent No. 2018508 C1, 5C 5/00. Solid fuel well gas generator. Kroshchenko V.D., Kolyasov S.M. et al. 01/02/1990, publ. 08/30/1994, bull. No. 16.

3. RF patent No. 20047744 C1, 6 E21B 43/11, 43/26. Device for stimulating the formation. Gaivoronsky I.N., Kroshchenko V.D. et al. 03/23/1992, publ. 11/10/1995, bull. No. 31.

4. RF patent No. 2106485, IPC E21B 43/263. A method for processing a bottomhole formation zone and a device for its implementation. Krasnoshchekov Yu.I., Samoshkin V.I., Zansokhov L.G. et al. 08/25/1995, publ. 03/10/1998.

5. RF patent No. 2183740 C1, 6 E21B 43/263. Sectional uncharged charge for gas-dynamic impact on the formation. Paderin M.G., Gazizov F.M. et al. 08/22/2001, publ. 06/20/2002.

6. RF patent No. 2175059, MKI E21B 43/263. Solid fuel gas generator with adjustable pulse for stimulation of wells. Kroshchenko V.D., Gribanov N.I., Gaivoronsky I.N. et al. 10/06/1999, publ. 10/20/2001.

7. RF patent No. 2261990, IPC E21B 43/263. The method of thermogasochemical effects on the reservoir and solid fuel charge for its implementation. Dyblenko V.P., Sharifullin R.Ya., Lysenkov A.P. et al. 08/14/2003, publ. 10/10/2005.

8. RF patent No. 2339810, IPC 21 V 43/263. Solid fuel gas generator for thermogasochemical and vibro-microwave treatment of wells. Pelykh N.M., Fedchenko N.N., Bogdanov S.Yu., Kuznetsova L.N., Zaripov F.R. Claim 03/02/2007, publ. 11/27. 2008, bull. No. 33 is a prototype.

9. Pelykh N.M. Unsteady combustion of solid fuel charges and its use in the national economy. The dissertation for the degree of Doctor of Technical Sciences. Perm, 2002.

Claims (2)

1. A solid fuel device for treating wells, including cylindrical powder tube charges, including igniter or igniter ones, with different channel diameters and the ratio of charge channel lengths to channel diameters (20-40): 1 and a load-carrying cable with structural fasteners, characterized in that the device further includes cylindrical powder tube charges of smaller diameters, which have the ratio of the lengths of the charge channels to the diameters of the channels (6-80): 1 and the ratio of the outer diameters of the charges larger and larger diameters (0.6-0.95): 1, while charges of different diameters alternate, in addition, charges with smaller diameters and ratios of channel lengths to channel diameters (40-80): 1 have external ring grooves and through channels at the place of the grooves, and the charges of a larger diameter have holders to protect them from friction in the well, while at the ends of the alternating charges are fixed disks with annular protrusions that enter into each other when assembling the charges. 2. A method of treating the bottom-hole zone of the formation using a solid fuel device, which includes creating excess pressure in the well by exposing the formation to the formation of gaseous combustion products of cylindrical powder tube charges with different channel diameters and the ratio of the length of the charge channels to their diameters (20-40): 1, characterized in that the overpressure in the well is created by exposing the formation to the formation of gaseous combustion products of cylindrical powder tube charges of smaller diameters, alternating with charges of a larger diameter tra, while charges of a smaller diameter have a ratio of channel lengths to channel diameters (6-80): 1 and the ratio of the outer diameters of charges of a smaller and larger diameter (0.6-0.95): 1, and at temperatures of 60-90 ° C and pressures of 20-40 megapascals in the well, eliminating charge discontinuities with ratios of channel lengths to channel diameters (40-80): 1 per set of fragments with an abnormal increase in pressure due to a critical increase in pressure drop in the axial channels of burning charges relative to the environment, is achieved by dividing these charges into two separate fr agent at the place of the annular grooves when meeting the fronts of combustion from the outer surfaces of the charges and from their channels.

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