RU2485306C1 - Method of hydraulic fracturing of well formation - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: method involves perforation of well walls at formation interval with channels with the depth that is not less than length of stress concentration zone in rocks from the well shaft; lowering of pipe string with packer; installation of packer above roof of perforated productive formation; pumping to under-packer zone of fracturing fluid gel to carry out formation hydraulic fracturing (FHF); creation of formation hydraulic fracturing pressure in under-packer zone and pumping of fracturing fluid gel with binding agent of fractures to the formed formation fracture. According to the invention, before formation hydraulic fracturing is performed, the pipe string is filled with process liquid and total volume of fracturing fluid gel is determined as per analytical expression. Then, formation hydraulic fracturing is performed. First, fracturing fluid gel is pumped without adding any binding agent for creation of fracture. Then, the rest volume of fracturing fluid gel with binding agent of fractures is pumped. As a binding agent of fractures there used is superlight proppant with the fraction of 20/40 mesh by gradual increase in concentration of the proppant in fracturing liquid of 200 kg/mto 1000 kg/m. As fracturing fluid gel there used is a line gel with simultaneous addition of a borate cross-linking agent and a destructor. Borate cross-linking agent is added to the line gel with concentration of 2.0 to 4.0 l/m, which is sufficient for complete cross-linking of fracturing fluid gel at the well perforation zone. The destructor is added with gradual increase in concentration by 0.15 kg/m, starting from the concentration of 1.0 kg/m. Upon completion of pumping of fracturing fluid gel with the binding agent of fractures to the pipe string there performed is their forcing-through to the formation with process liquid. Exposure is performed during the period of time, which is necessary for pumping pressure drop by 70-80% of forcing-through pressure to the formation of fracturing fluid gel with the binding agent of fractures; the packer is unpacked, and the above packer and the pipe string is removed to the surface.EFFECT: improving efficiency of the method owing to increasing the width of fracture and value of its penetration and reduction of the commissioning period of the well.3 ex, 1 dwg

Description

The invention relates to the oil and gas industry and may find application to increase the productivity of both newly commissioned and existing production and injection wells.

A known method of acid treatment of underground formations (patent RU No. 2122633 IPC E21B 43/27, publ. 1998), which includes injecting into the formation at a pressure above the fracturing pressure of acid agents and proppant.

The disadvantage of this method is that it does not allow to increase the productivity of wells and to develop for injection wells in clay reservoirs and low-power sandstones, in addition, the process of implementing the method differs in the duration of the process and high cost.

Also known is a method of hydraulic fracturing by pumping a liquid under high pressure into a well, which provides a postcard in the formation, in particular a productive formation, of existing cracks or the creation of new cracks, which greatly improve the hydrodynamic connection between the formation and the well. At the same time, a crack fixer is introduced into the fracture fluid — a proppant (for example, quartz sand or walnut shells or glass balls) that penetrate the cracks, remain in them when the well is put into operation and keep the cracks open (see, for example , Prince Usachev P.M., Hydraulic fracturing, M .. Nedra. 1986. p. 164).

The disadvantages of this method are:

- firstly, the high complexity and high cost of implementing the method, due to the fact that hydraulic fracturing requires a large number of pumping units of sand mixing machines, tank trucks, and pumping units are designed to pump liquid media under pressure up to 70 MPa, and sand mixing machines are designed to transportation of crack fixer - proppant, preparation of sand-liquid mixture and its submission to the reception of pumping units. Tankers are used for transporting liquids and supplying them to sand mixing and pumping plants, while for tying the mouth it is necessary to use special high-strength valves designed for high pressure up to 70 MPa. To protect the production string from high pressure during hydraulic fracturing according to the method described above, the use of high-strength packers with anchor devices is mandatory;

- secondly, when high pressures are reached, not only the productive formation ruptures, but also the overlying and / or underlying shielding bridges. This leads to intensive watering of the extracted products and, in general, to a decrease in the efficiency of work, in particular, work to intensify oil production. In addition, a full-scale hydraulic fracturing leads to the formation of a large-scale fracture, as a rule, a single one, with a long extension far beyond the boundaries of the zone of mudding. The intensified formation does not drain the product in this case with the entire thickness of the formation, but leads to catastrophic absorption of the working agent both at the stage of hydraulic fracturing and at subsequent stages of stimulation.

The closest is the method of hydraulic fracturing (Fracturing) in the well (patent RU No. 2358100, IPC E2IB 43/26, published June 10, 2009), including perforation of the walls of the well with channels at least a depth of the stress concentration zone in the rocks from the existing wellbore wells and injection into the well of the gel-like fracturing fluid "Himeko" in portions: the first - in the amount of 3-8 m ³ ; the second - in a volume of 10-12 m ³ and with a crack crack fastener; the third - in a volume of 2-3 m ³ , after which the portions of gel-like liquid are forced into the reservoir with a flow rate of 0.5-1 m ³ / min.

The disadvantages of this method are:

- firstly, the gel-like (gelled) fracturing fluid does not provide sufficient crack opening in the formation, and the large friction pressure losses that occur during the injection of the gelled fracturing fluid cause high loads on the pumping equipment and can lead to failure of this equipment ;

- secondly, the low efficiency of hydraulic fracturing due to uneven consolidation of the fracture in the reservoir, i.e. a crack during subsequent operation of a production or injection well closes in a short period of time, which leads to a decrease in the productivity of production and injection wells;

- thirdly, a sufficiently long term for putting a well into operation after this hydraulic fracturing.

The objectives of the invention are to increase the width of the fracture and its penetration into the formation during hydraulic fracturing, to reduce friction pressure losses, as well as to increase the efficiency of hydraulic fracturing by uniformly fixing the fracture in the formation by using ultralight proppant of different densities and shortening the life of the well after commissioning hydraulic fracturing.

The problem is solved by the method of hydraulic fracturing in the well, including perforation of the walls of the well in the interval of the channel with channels of depth not less than the length of the stress concentration zone in the rocks from the well bore, descent of the pipe string with the packer, the packer landing over the roof of the perforated reservoir, injection into the sub-packer zone of the gelled fracturing fluid for conducting hydraulic fracturing, creating in the sub-packer zone of hydraulic fracturing pressure and pushing into the formed fracture This is a gelled fracture fluid with crack fixer.

What is new is that before hydraulic fracturing, the pipe string is filled with process fluid, the total volume of gelled fracturing fluid is determined by the following formula:

Vg = k · Hp,

where Vg is the total volume of the fracture fluid, m ³ ;

k = 11-12 - conversion factor, m ³ / m;

Np - the height of the interval of perforation of the reservoir, m,

then hydraulic fracturing is carried out, while first the gelled fracturing fluid is injected in a volume of 0.2-0.25 Vg without adding a fastener to create a crack, then the remaining volume of the gelled fracturing fluid is injected with a crack fixing, and ultralight fraction proppant is used as a crack fixing 20/40 mesh, gradually increasing the proppant concentration in the fracturing fluid from 200 kg / m ³ to 1000 kg / m ³ , and a linear gel with the addition of a borate crosslinker is used as a gelled fracturing fluid I and the destructor, while the borate crosslinker is introduced into a linear gel with a concentration of from 2.0 to 4.0 l / m ³ sufficient to completely crosslink the gelled fracturing fluid near the well perforation zone, and the destructor is introduced with a gradual increase in concentration by 0.15 kg / m ³ , starting from a concentration of 1.0 kg / m ³ , after the completion of the injection of the gelled fracturing fluid with the crack fixer into the pipe string, they are pushed into the formation by the process fluid, soaking is carried out for the time required for the injection pressure to drop by 70- 80% of the pressure pro avki a gelled liquid fracturing with binders cracks raspakerovyvayut packer, it is removed and the pipe string to the surface.

The drawing schematically shows the implementation of the method of hydraulic fracturing in the well.

The proposed method of hydraulic fracturing in a well is as follows.

The method of hydraulic fracturing in the well 1 (see drawing) includes perforating the walls of the well 1 with channels 2 with a depth not less than the length of the stress concentration zone in the rocks from the wellbore 1 by any known method, for example, as described in patent RU No. 2358100, IPC 8 E2IB 43/26, publ. in bull. No. 16 dated 06/10/2009. Next, a pipe string 3 is lowered into the well in the hydraulic fracturing zone, for example, a tubing string 73 mm with a packer 4 so that the packer is 5-10 m above the roof of layer 5 of formation 6 fracturing, and the lower end of the column is coarse 3 - at the level of the roof 5 of the layer 6.

Packer 4 of any known design is planted, for example, a through packer with an anchor with a mechanical rotary installation PRO-YaM2-YaG1 (F) or PRO-YaMZ-YaG2 (F) (100 MPa) manufactured by the Packer research and production company (g October, Republic of Bashkortostan, Russian Federation). Thus, annular space 7 of the well 1 is sealed in order to protect the walls of the well from the effects of high pressures arising during hydraulic fracturing.

Before hydraulic fracturing, the pipe string 3 is filled with process fluid, for example waste water with a density ρ = 1180 kg / m ³ , and the total volume of the gelled fracturing fluid is determined by the following formula:

where Vg is the total volume of the fracture fluid, m ³ ;

k = 11-12 - conversion factor, m ³ / m;

NP - the height of the interval of perforation of the reservoir, m

In this formula, the transfer coefficient is obtained experimentally and depends on the reservoir properties of the formation in which hydraulic fracturing is performed, for example, the opening interval height Нп = 5 m. Then, substituting into formula (1), we obtain the total volume of the injected gellated fracturing fluid:

Vg = k · Hp,

Vg = 12 (m ³ / m) · 5 (m) = 60 m ³ .

A gelled fracturing liquid is prepared, which is used as a linear gel with the simultaneous addition of a borate crosslinker and a destructor, which is prepared by any known method, for example, as described in patent RU No. 2381252, IPC 8 C09K 8/68, publ. in bull. No 4 on 02/20/2010

Then proceed to hydraulic fracturing. To do this, first inject into the well 1 (see Fig. 1) through a pipe string 3 of gelled liquid to break a linear gel in a volume of (0.2-0.25) Vg (without adding a fastener to create cracks), i.e. substituting the values: 0.25 · Vg = 0.25 · 60 m ³ = 15 m ³ .

The linear gel is injected with the simultaneous addition of a borate crosslinker and a destructor. The borate crosslinker is introduced into a linear gel with a concentration of from 2.0 to 4.0 l / m ³ sufficient to completely crosslink the time of the gelled fracturing fluid directly near the perforation zone of the well 1 when the gelled fluid enters the fracture. The borate crosslinker makes it possible to obtain a crosslinked gel from a linear gel when it enters the formation 6.

Simultaneously with the addition of a borate crosslinker, a destructor is introduced into the gelled fracturing fluid. The introduction of a destructor into a linear gel allows accelerating the time of putting a well into operation after hydraulic fracturing due to the accelerated decomposition of the gel in the formation. The destructor is introduced with a gradual increase in concentration by 0.15 kg / m ³ , starting from a concentration of 1.0 kg / m ³ . The maximum concentration of the destructor in the gelled fracturing fluid is 1.3-1.45 kg / m ³ .

The BS-1 borate stapler is used according to TU 2499-069-17197708-2003. The HV destructor according to TU 2499-074-17197708-2003 or the HV-1 destructor according to TU 2499-012-54651030-2005.

The gelled fracturing fluid is injected through perforation channels 2, for example, with a flow rate of 1.5–2 m ³ / min until a rock is broken in formation 6 and a crack 8 is formed, which will be indicated by a drop in injection pressure and an increase in injectivity of formation 6. For example, a pressure of 30 MPa was reached due to the formation of a crack 8, a decrease in the injection pressure of the gel-like rupture fluid by 20-25%, i.e. up to 22 MPa, while the injectivity of the formation 6 increased by 25-30%, for example, from 1.2 m ³ / min to 1.6 m ³ / min, while at the time of the drop in the injection pressure (during crack formation 8) into the column pipes 3 of well 1, a gel-like fracturing fluid was injected — a linear gel in the volume of 0.25 · Vg = 0.25 · 60 m ³ = 15 m ³ .

Then the remaining volume of the gelled fracturing fluid is pumped in - a linear gel mixed with crack fixer, i.e. in the volume Vg-0.25 · Vg = 60 m ³ -15 m ³ = 45 m ³ , moreover, ultralight proppant fraction 20/40 mesh, with a concentration of 200 kg / m ³ , gradually increasing the concentration of proppant in the liquid is used as crack cracking agent rupture starting from 200 kg / m ³ and ending with 1000 kg / m ³ , i.e. 200 kg / m ³ , 400 kg / m ³ , 600 kg / m ³ , 800 kg / m ³ , 1000 kg / m ³ , and the linear gel with proppant is injected, for example, with a flow rate of 1.5-2 m ³ / min The proppant fraction 20/40 mesh is made according to GOST R 51761-2005 - "Aluminosilicate proppants. Technical conditions ”and is produced by the Borovichi Refractory Plant (Borovichi, Republic of Belarus). The ultralight proppant of the 20-40 mesh fraction does not sink in the gelled fracturing fluid, a linear gel, due to which it is forced through the perforation channels 2 over the entire volume of the crack 8.

After completion of the injection of the gelled fracturing fluid with a fixture (proppant) of a concentration of 1000 kg / m ³ , they are forced into the reservoir 6 with process fluid, which is used as wastewater with a density of: ρ = 1180 kg / m ³ , for example, under a pressure of 32 MPa.

The volume of the process fluid, sufficient for the complete injection into the formation of a linear gel with proppant from the pipe string 3, is taken to be equal to one and a half times the internal volume of the pipe string 3, lowered into the well 1.

Extract is carried out for the time required for the injection pressure to drop by 70-80% of the pressure of the gelled fracturing fluid into the reservoir with crack cracking agent, for example, from 32 MPa to 7 MPa. Then packer 4 is unpacked and removed with pipe string 3 from well 1.

Examples of the practical implementation of the method

Example 1

Well 1 operates a reservoir located at a depth of 1700 m. The height of the perforation interval of the reservoir is Np = 5 m.

In the well 1, the walls of the well were perforated by channels 2 with a depth not less than the length of the stress concentration zone in the rocks from the well bore. Next, a column of tubing 3 with a nominal diameter of 73 mm and a packer 4 was lowered into the well into the hydraulic fracturing zone so that the packer was 5-10 m above the roof 5 of formation 6 to be fractured, and the lower end of the pipe string 3 was at the roof level 5 strata 6.

Packer 4 was planted in well 1, thus sealing the annular space 7 of well 1.

Before hydraulic fracturing, the pipe string 3 was filled with process fluid — waste water with a density ρ = 1180 kg / m ³ .

The total volume of the gelled fracturing fluid was determined by the following formula:

Vg = k · Hp = 12 (m ³ / m) · 5 (m) = 60 m ³ ,

where k = 11-12 - conversion coefficient, m ³ / m;

NP - the height of the interval of perforation of the reservoir, in this example = 5 m

A gelled fracturing liquid was prepared, which was used as a linear gel with the addition of a borate crosslinker and a destructor.

Then we proceeded to hydraulic fracturing. To do this, first, they injected into the well 1 (see Fig. 1) through a pipe string 3 of a gelled fracturing fluid — a linear gel in a volume of 0.2 Vg (without adding a fastener to create cracks), i.e. substituting the values: 0.2 · Vg = 0.2 · 60 m ³ = 12 m ³ .

The linear gel was injected with the simultaneous addition of a borate crosslinker and a destructor. The BS-1 borate crosslinker according to TU 2499-069-17197708-2003 was introduced into a linear gel with a concentration of 2.0 l / m ³ so that the time-crosslinked gelled fracture was completely crosslinked directly at the hole perforation zone 1 at the entrance of the gelled fluid into the crack. Simultaneously with the addition of a borate crosslinker, an XB destructor according to TU 2499-074-17197708-2003 was introduced into the gelled fracturing liquid. The destructor was introduced with a gradual increase in concentration by 0.15 kg / m ³ , starting from a concentration of 1.0 kg / m ³ , at the maximum concentration of the destructor in the gelled fracturing fluid was 1.3 kg / m ³ .

The gelled fracturing fluid was injected through perforation channels 2 with a flow rate of 1.5 m ³ / min until the formation rock 6 was fractured and crack 8 formed. In this case, the crack initiation pressure was 30 MPa and the hydraulic fracturing process pressure was 22 MPa.

Then, the remaining volume of the gelled fracturing fluid, a linear gel mixed with crack fixer, was pumped, i.e. in the volume Vg-0.2 · Vg = 60 m ³ -12 m ³ = 48 m ³ with a flow rate of 1.5 m ³ / min, and ultralight proppant according to GOST R 51761-2005 - “Aluminosilicate proppants. Technical conditions ”produced by the Borovichi Combine of Refractories (Borovichi, Republic of Belarus) fraction 20/40 mesh. Moreover, the gelled fracturing fluid was pumped into the mixture with proppant with a gradual increase in the proppant concentration in the mixture starting from 200 kg / m ³ and ending with 1000 kg / m ³ , i.e. 200 kg / m ³ , 400 kg / m ³ , 600 kg / m ³ , 800 kg / m ³ , 1000 kg / m ³ .

After completion of the injection of the gelled fracturing fluid in the mixture with the crack holder - proppant, the gelled fracturing fluid was pushed into the formation 6 by the process fluid, which was used as wastewater with a density of ρ = 1180 kg / m ³ under a pressure of 32 MPa.

The volume of the process fluid, sufficient for full linear injection of proppant gel from the pipe string 3 into the formation, was taken equal to one and a half times the internal volume of the pipe string 3, lowered into the well 1.

They made an exposure for the time required for the injection pressure to drop by 70%, from 32 MPa to 9.6 MPa. After that, the packer 4 was unpacked and removed with the pipe string 3 from the well 1.

Example 2

Well 1 operates a reservoir located at a depth of 1700 m. The height of the perforation interval of the reservoir is Np = 5 m.

In the well 1, the walls of the well were perforated by channels 2 with a depth not less than the length of the stress concentration zone in the rocks from the well bore. Next, a column of tubing 3 with a nominal diameter of 73 mm and a packer 4 was lowered into the well into the hydraulic fracturing zone so that the packer was 5-10 m above the roof 5 of formation 6 to be fractured, and the lower end of the pipe string 3 was at the roof level 5 strata 6.

Packer 4 was planted in well 1, thus sealing the annular space 7 of well 1.

Before hydraulic fracturing, the pipe string 3 was filled with process fluid — waste water with a density ρ = 1180 kg / m ³ .

The total volume of the gelled fracturing fluid was determined by the following formula:

Vg = k · Hp = 12 (m ³ / m) · 5 (m) = 60 m ³ ,

where k = 11-12 - conversion coefficient, m ³ / m;

NP - the height of the interval of perforation of the reservoir, in this example = 5 m

A gelled fracturing liquid was prepared, which was used as a linear gel with the addition of a borate crosslinker and a destructor.

Then we proceeded to hydraulic fracturing. To do this, first, they injected into the well 1 (see Fig. 1) through a pipe string 3 of a gelled fracturing fluid — a linear gel in a volume of 0.23 Vg (without adding a fastener to create cracks), i.e. substituting the values: 0.23 · Vg = 0.23 · 60 m ³ = 13.8 m ³ .

The linear gel was injected with the simultaneous addition of a borate crosslinker and a destructor. The BS-1 borate crosslinker according to TU 2499-069-17197708-2003 was introduced into a linear gel with a concentration of 3.0 l / m ³ so that the time crosslinking of the gelled fracturing fluid occurs directly near the perforation zone of the well 1 at the entrance of the gelled fluid into the crack. Simultaneously with the addition of a borate crosslinker, an XB destructor according to TU 2499-074-17197708-2003 was introduced into the gelled fracturing liquid. The destructor was introduced into a linear gel with a gradual increase in concentration by 0.15 kg / m ³ , starting from a concentration of 1.0 kg / m ³ , while the maximum concentration of the destructor in the gelled fracturing fluid was 1.4 kg / m ³ .

The gelled fracturing fluid was injected through perforation channels 2 with a flow rate of 1.5 m ³ / min until the formation rock 6 was fractured and crack 8 formed. In this case, the crack initiation pressure was 31 MPa and the hydraulic fracturing process pressure was 24 MPa.

Then, the remaining volume of the gelled fracturing fluid, a linear gel mixed with crack fixer, was pumped, i.e. in the volume Vg-0.23 Vg = 60 m ³ -13.8 m ³ = 46.2 m ³ with a flow rate of 1.5 m ³ / min, and ultralight proppant according to GOST R 51761-2005 was used as a crack fixer - “Aluminosilicate proppants. Technical conditions ”produced by the Borovichi Combine of Refractories (Borovichi, Republic of Belarus) fraction 20/40 mesh. Moreover, the gelled fracturing fluid was pumped into the mixture with proppant with a gradual increase in the proppant concentration in the mixture starting from 200 kg / m ³ and ending with 1000 kg / m ³ , i.e. 200 kg / m ³ , 400 kg / m ³ , 600 kg / m ³ , 800 kg / m ³ , 1000 kg / m ³ .

After completion of the injection of the gelled fracturing fluid in the mixture with the crack holder - proppant, the gelled fracturing fluid was pushed into the formation 6 by the process fluid, which was used as sewage with a density of ρ = 1180 kg / m ³ , under a pressure of 34 MPa.

The volume of the process fluid, sufficient to fully sell the linear gel with proppant from the pipe string 3 into the formation, was taken equal to one and a half times the internal volume of the pipe string 3, lowered into the well 1.

They made an exposure for the time necessary for the injection pressure to drop by 75%, from 34 MPa to 8.5 MPa. After that, the packer 4 was unpacked and removed with the pipe string 3 from the well 1.

Example 3

Well 1 operates a reservoir located at a depth of 1700 m. The height of the perforation interval of the reservoir is Hp = 5 m.

In the well 1, the walls of the well were perforated by channels 2 with a depth not less than the length of the stress concentration zone in the rocks from the well bore. Next, a column of tubing 3 with a nominal diameter of 73 mm and a packer 4 was lowered into the well into the hydraulic fracturing zone so that the packer was 5-10 m above the roof 5 of formation 6 to be fractured, and the lower end of the pipe string 3 was at the roof level 5 strata 6.

Packer 4 was planted in well 1, thus sealing the annular space 7 of well 1.

Before hydraulic fracturing, the pipe string 3 was filled with process fluid - waste water with a density ρ = 1180 kg / m ³ .

The total volume of the gelled fracturing fluid was determined by the following formula:

Vg = kNp = 12 (m ³ / m) 5 (m) = 60 m ³ ,

where k = 11-12 - conversion coefficient, m ³ / m;

NP - the height of the interval of perforation of the reservoir, in this example = 5 m

A gelled fracturing liquid was prepared, which was used as a linear gel with the addition of a borate crosslinker and a destructor.

Then we proceeded to hydraulic fracturing. To do this, they first injected into the well 1 (see Fig. 1) through a pipe string 3 of a gelled fracturing fluid — a linear gel in a volume of 0.25 Vg (without adding a fastener to create cracks), i.e. substituting the values: 0.25 · Vg = 0.25 · 60 m ³ = 15 m ³ .

The linear gel was injected with the simultaneous addition of a borate crosslinker and a destructor. The BS-1 borate crosslinker according to TU 2499-069-17197708-2003 was introduced into a linear gel with a concentration of 4.0 l / m ³ so that the time-crosslinked gelled fracture was completely crosslinked directly at the hole perforation zone 1 at the entrance of the gelled fluid into the crack. Simultaneously with the addition of a borate crosslinker, an XB destructor according to TU 2499-074-17197708-2003 was introduced into the gelled fracturing liquid. The destructor was introduced into a linear gel with a gradual increase in concentration by 0.15 kg / m ³ , starting from a concentration of 1.0 kg / m ³ , while the maximum concentration of the destructor in the gelled fracturing fluid was 1.45 kg / m ³ .

The gelled fracturing fluid was injected through perforation channels 2 with a flow rate of 1.5 m ³ / min until the formation rock 6 was fractured and crack 8 formed. At that, the crack initiation pressure was 29 MPa, the hydraulic fracturing process pressure was 21 MPa.

Then, the remaining volume of the gelled fracturing fluid, a linear gel mixed with crack fixer, was pumped, i.e. in the volume Vg-0.25 · Vg = 60 m ³ -15 m ³ = 45 m ³ with a flow rate of 1.5 m ³ / min, and ultralight proppant according to GOST R 51761-2005 - “Aluminosilicate proppants. Technical conditions ”produced by the Borovichi Combine of Refractories (Borovichi, Republic of Belarus) fraction 20/40 mesh. Moreover, the gelled fracturing fluid was pumped into the mixture with proppant with a gradual increase in the proppant concentration in the mixture starting from 200 kg / m ³ and ending with 1000 kg / m ³ , i.e. 200 kg / m ³ , 400 kg / m ³ , 600 kg / m ³ , 800 kg / m ³ , 1000 kg / m ³ .

After completion of the injection of the gelled fracturing fluid in the mixture with the crack holder - proppant, the gelled fracturing fluid was pushed into the formation 6 by the process fluid, which was used as wastewater with a density ρ = 1180 kg / m ³ under a pressure of 31 MPa.

The volume of the process fluid, sufficient to fully sell the linear gel with proppant from the pipe string 3 into the formation, was taken equal to one and a half times the internal volume of the pipe string 3, lowered into the well 1.

They made an exposure for the time required for the injection pressure to drop by 80%, from 31 MPa to 6.2 MPa. After that, the packer 4 was unpacked and removed with the pipe string 3 from the well 1.

The proposed method of hydraulic fracturing in the well allows to increase the width of the crack and the amount of its penetration into the reservoir due to the simultaneous addition of a borate crosslinker and destructor into the fracture fluid (linear gel) during the formation of fracture fractures in the reservoir, and also allows to reduce the pressure loss due to friction in the pipes by 8-10% in the process of formation of a fracture fracture in the reservoir.

Improving the efficiency of hydraulic fracturing is achieved by uniformly fixing the fracture in the formation with an ultralight proppant of a fraction of 20/40 mesh of various densities with a gradual increase in concentration, while it is possible to keep the fracture in the open state for a long time, and this allows increasing production productivity by 10-15% or injection well.

Claims (1)

A method of hydraulic fracturing in a well, including perforation of the walls of the well in the interval of the channels with channels at least the length of the stress concentration zone in the rocks from the wellbore, lowering the pipe string with the packer, packing the packer over the roof of the perforated productive formation, injecting gelled fracturing fluid into the sub-packer zone for hydraulic fracturing, creating a fracturing pressure in the sub-packer zone and pushing the gelled fluid into the resulting fracture and with a crack fastener, characterized in that before the hydraulic fracturing, the pipe string is filled with process fluid, the total volume of the gelled fracture fluid is determined by the following formula:
V _g = k · H _p
where V _g - the total volume of the fluid gap, m ³ ;
k is the transfer coefficient (k = 11-12), m ³ / m;
N _p - the height of the interval of perforation of the formation, m, then produce hydraulic fracturing of the formation, while first injected gelled fracturing fluid in a volume of (0.2-0.25) V _g without adding a fastener to create a crack, then the remaining volume of gelled fracturing fluid is injected with a crack fixer; moreover, an ultralight proppant of a 20/40 mesh fraction is used as a crack fixer, gradually increasing the proppant concentration in the fracturing fluid from 200 kg / m ³ to 1000 kg / m ³ , and a linear gel with od by the addition of a borate crosslinker and a destructive agent, the borate crosslinker is introduced into a linear gel with a concentration of 2.0 to 4.0 l / m ³ sufficient to completely crosslink the gelled fracturing fluid near the well perforation zone, and the destructor is introduced with a gradual increase in concentration by 0.15 kg / m ^3, starting with a concentration of 1.0 kg / m ^3, after the injection of fracturing fluids gelled with binders cracks in the pipe string prodavku produce them in the process fluid reservoir, produce exposure for a time required for a hell pressure injection by 70-80% of prodavki pressure in the gelled fracturing fluid with binders cracks raspakerovyvayut packer, it is removed and the pipe string to the surface.

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