RU2522031C1 - Method of fitting well screen in horizontal steam-injection well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method includes drilling of a horizontal well, running in of a production casing with a well screen with shear plugs in openings, and packers. In the drilling process permeability properties are defined, the borehole is divided into zones having the permeability properties differentiating per 1.5-1.6 times, a flow area of the screen openings and a number of openings for each zone is selected. At the mouth the well screen is equipped with a shear funnel and water-swellable packers from the outside, the string is run in into the well and the well screen is fitted so that the water-swellable packers are within boundaries of the formation zones with different properties. The hole is lined, and the following layout is assembled at the mouth: a fishing magnet, a pusher, a rigid centraliser with overflow channels. The assembly is run in to the well until the pusher is rested on the shear funnel, the string is slacked off, and the shear funnel is moved until it rests on the first row of the shear plugs, the string is slacked off completely to the funnel and the first row of the shear plugs is destroyed. The string is moved from the mouth to the bottomhole and the next row of the shear plugs is destroyed and fixed by the fishing magnet. The string is slacked off completely to the funnel again and the remaining rows of plugs are destroyed, the pipe string is run out with the assembly. Openings are isolated in the lower perimeter of the well screen.

EFFECT: improved quality of the formation drilling, reduced time for the well screen fitting.

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Description

The invention relates to the field of development of highly viscous oil fields and can be used to open productive formations with steam injection horizontal wells and equip them with filters in this interval.

A known method of completing construction of a well (patent RU No. 2134341, IPC E21B 43/11, publ. 08/10/1999, bull. No. 22), including the descent into the drilled well of the production string with a filter equipped with plugs in the holes of the filter from the material being destroyed during chemical exposure, installation of a production string in a well with a filter located in the interval of the reservoir, plugging of a production string with a filter, waiting for the grouting material to solidify, lowering the tubing string into the well, s filling the well with a chemical reagent, holding the well for the time of destroying the plugs of the filter openings, injecting gas with a variable pressure until the injected gas is connected to the formation fluid and cleaning the well of reaction products, according to the invention, a material soluble with a chemical reagent for destroying the plugs is added to the grouting material in the filter interval openings of the filter, before filling the well with a chemical reagent, fill the cavity of the tubing with gas when the annulus is open at the wellhead and push the well fluid to the bottom of the tubing, and after filling the well with a chemical reagent, it is pushed with gas into the annulus during the installation interval of the filter, after which the annulus at the wellhead is closed, and the subsequent injection of gas is carried out by the compressor.

The disadvantages of this method:

- firstly, the low quality of the opening of the reservoir due to the plugging of the production string filter, while behind the filter a cement stone is formed, which worsens the hydrodynamic connection of the well with the reservoir;

- secondly, the low efficiency of the development of high-viscosity oil deposits, due to the fact that when a water breakthrough occurs in any filter interval, all produced products are flooded;

- thirdly, the imperfection of opening the reservoir, due to the fact that the number of holes made on the filter body into which the plugs soluble by the chemical agent are installed do not take into account the filtration-capacitive characteristics of individual sections of the reservoir, which means that in areas with high reservoir properties of the reservoir, the filter bandwidth will be limited, and in areas with low reservoir characteristics of the reservoir, on the contrary, the filter bandwidth udet exceed the scope of selection of high viscosity oil from this zone.

Also known is a method of completing construction of a well (AS SU No. 1210507, IPC E21B 43/08, published 07.12.1987), including the descent of a production casing equipped with a filter with plugs in the holes of a filter made of material that is destroyed by chemical exposure, installation of the production string in the well with the filter in the interval of the reservoir, plugging of the production string with the filter, waiting for the hardening of the grouting material, descent of the tubing string into the well, filled e wellbore chemical reagent shutter wells in the destruction of the filter plugs holes, gas injection with variable pressure to a compound of the discharge gas with the formation fluid and cleaning the well from the reaction products.

The disadvantages of this method:

- firstly, when plugging a production string with a filter, the space between the reservoir and the filtration channels in the filter ribs is blocked by grouting material, which reduces the productivity of the well;

- secondly, there is an inefficient opening of the reservoir due to the fact that the number of holes made through the filter body into which the plugs soluble by the chemical agent are installed do not take into account the filtration-capacitive characteristics of individual sections of the reservoir, which means that in areas with high reservoir properties, the filter capacity will be limited, and in areas with low reservoir properties, on the contrary, the filter capacity will exceed the amount of selection of high viscosity oil from this zone.

The closest in technical essence is the method of installing a downhole filter (patent RU No. 2378495, IPC E21B 43/08, publ. 01/10/2010, bull. No. 1), including the descent into the drilled well of at least one downhole filter, installed in the production casing and containing cut-off plugs in the filter openings, and a centralizer is installed on each well filter before being lowered into the well, which is fixed to the downhole filter pipe that is free of the filter element, above the well filters column packers, the number of which corresponds to the number of productive formations, after the casing string is lowered, wash the well and activate the packers one by one, closing the central holes in the packer seats with a discharge element, for example a ball, with subsequent pressure increase inside the production string and forcing cement into the annulus for fixing the production string above the reservoir, after the cement has hardened, drill cementing plugs, seats akers and dumping elements, and also cut off the plugs of all filters.

The disadvantages of this method are:

- firstly, a complex technological process associated with the alternate planting of packers, the number of which corresponds to the number of productive formations, while the packers are planted by covering the central holes in the packer seats with a discharge element, such as a ball, followed by a rise in pressure inside the casing and forcing cement solution into the annulus above the reservoir, after cement hardening, cementing plugs, packer seats and discharge elements are drilled;

- secondly, the low reliability of the method, due to the fact that the packers are seated by covering the central holes in the saddles of the packers with a discharge element, for example a ball, and in horizontal wells there is a high probability of an leaky landing of the discharge element on the saddle of the packer;

- thirdly, the long process of destruction of the cut-off plugs, since their destruction is carried out simultaneously with the drilling of cementing plugs, saddles of packers and discharge elements;

- fourthly, inefficient opening of the reservoir, since the number of shear plugs installed on the filter body does not take into account the reservoir properties of the formation, therefore the filter capacity will not correspond to the reservoir characteristics of individual sections of the formation, for example, in areas with high permeability, the filter capacity will be limited, and in areas with low permeability, on the contrary, the filter capacity will exceed the volume of high-viscosity oil from this zone.

The technical objectives of the proposal are to increase the reliability and efficiency of installing a downhole filter in a horizontal steam injection well, simplifying the process of implementing the method, and also reducing the duration of the destruction of sheared plugs.

The tasks are solved by installing a downhole filter in a horizontal injection well, including drilling a horizontal injection well, lowering a production casing equipped with a downhole filter with cut-off plugs in the holes and packers, securing the production casing in the well with the filter in the interval of the reservoir, destruction cut-off plugs in the filter holes.

New is that in the process of drilling a horizontal well, filtration-capacitive characteristics are determined, their change within the reservoir along the horizontal wellbore is divided into zones that differ in filtration-capacitive characteristics by 1.5-1.6 times, after which selects the cross-sectional area of the filter openings depending on the filtration-capacitive characteristics and the number of holes for each zone separately, make holes in separate sections of the filter and set in they are shear plugs, then at the wellhead the filter is equipped inside with a shear funnel fixed by a shear element relative to the filter, and outside with annular water swellable packers, a production string with a filter is lowered into the drilled horizontal well and the filter is installed in the well so that the water swell packers are at the boundaries of the zones formation with different filtration-capacitive characteristics, the production string is fastened, then the bottom assembly is assembled at the wellhead top: magnetic catcher, pusher, rigid centralizer with transfer channels on the periphery, lower the assembly on the pipe string into the well until the push rod stops in the shear funnel, unload the pipe string by 5 kN and destroy the shear element, move the shear funnel through the pusher to the stop in the first row shear plugs, completely unload the pipe string to the shear funnel and destroy the first row of shear plugs, which after destruction is fixed on a magnetic catcher, then move the pipe string from the mouth to the bottom and destroy the a series of cut-off plugs with their fixation on a magnetic catcher, weighing a pipe string or pumping process fluid from the wellhead, followed by a well flushing, after which the pipe string is completely again unloaded onto a shear funnel and the remaining rows of cut-off plugs are destroyed over the entire filter section, the pipe string is removed from arrangement, then a string of flexible pipes is lowered into the well before the bottom, it is moved from the bottom to the mouth along the entire length of the filter, and at the same time the cement pipe is injected along the string of flexible pipes remaining, which isolate the openings formed in the lower perimeter of the filter.

Figure 1, 2, 3, 4 schematically shows the proposed method of installing a downhole filter in a steam horizontal injection well.

The proposed method is as follows.

In the process of drilling a horizontal wellbore of a steam injection well, filtration-capacitive characteristics and their change within the reservoir 1 (Fig. 1) are determined along the horizontal wellbore 2. The horizontal wellbore 2 is divided into zones that differ in filtration-capacitive characteristics of 1.5- 1.6 times.

For example, the length L of the barrel of the steam injection horizontal well 2 in the reservoir 1 is 190 m, the filtration-capacitive characteristics and their change along the trunk of the horizontal well 2 were determined as follows:

zone 3 ′ - permeability of 0.85 D, length L ₁ = 90 m;

zone 3 ′ ′ - permeability of 1.3 D, length L ₂ = 60 m (1.53 times relative to zone 3 ′);

zone 3 ″ ″ - permeability 2.0 D, length L ₃ = 40 m (1.54 times relative to zone 3 ″).

The boundaries of zones 3 ′, 3 ″, 3 ″ ″ are the boundaries of lengths L ₁ , L ₂ , L ₃ , in which the filtration-capacitive properties differ by 1.5-1.6 times.

Then, the cross-sectional area (filter bandwidth) of the openings 4, 4 ′, 4 ′ ′ ... 4 ⁿ (shown in Fig. 1 conditionally) of the filter 5 (depending on the filtration-capacitive characteristics) is selected.

Filter 5 is made of casing with an outer diameter of 168 mm and an inner diameter of 140.3 mm.

The cross-sectional area of the filter 5 is 154.5 cm ² .

The selection of the area of the bore holes 4, 4 ′, 4 ″ ... 4 ’ ^{n of the} filter 5 for each zone 3 ′, 3 ″, 3 ″ ″ is carried out in any known manner, for example, as described in patent RU No. 2134341, IPC E21B 43/11, publ. in bull. No.22 of 08/10/1999

Next, determine the number of holes 4, 4 ', 4 "... 4", performed in the filter 5 in each zone, by calculation by the formula:

N _Zi = (K ₁ / K _i ) · (4 · Fk / π · do ² ) · L _i / k,

where K ₁ - the minimum permeability of the rocks in the zone of the productive part, opened by a horizontal well, D;

K _i - rock permeability in the zone of the productive part, opened by a horizontal well, D;

Fk is the cross-sectional area of the filter, cm ² ;

π = 3.14;

do - the bore diameter of plugs 6, 6 ′, 6 ′ ′ ... 6 ⁿ (shown in FIG. 2 conventionally) inserted into the holes 4, 4 ′, 4 ′ ′ ... 4 ⁿ (FIG. 1) of filter 5, cm, do = 1.2 cm;

L _i is the length of the zone of the productive part of the horizontal well;

k is the duty ratio, taking into account that the development of a highly viscous oil deposit is carried out through the upper perimeter of filter 2, we take k = 5.

Thus, substituting the values in the formula, we get the number of holes made in the filter 5 in each individual zone:

N _Z1 = (0.85 / 0.85) · (4 · 154.5 / 3.14 · 1.2 ² ) 90/5 = 2460 pcs.

N _Z2 = (0.85 / 1.3) · (4 · 154.5 / 3.14 · 1.2 ² ) 60/5 = 1072 pcs.

N _Z3 = (0.85 / 2.0) · (4 · 154.5 / 3.14 · 1.2 ² ) 40/5 = 465 pcs.

For example, for a zone of length L ₂ with the number of holes 1072 pcs. perform: 8 holes with a diameter of 25 mm around the perimeter of the filter 5, the distance between the rows of radial holes is 0.45 m, i.e. 60 m / (1072 m / 8) = 0.45 m. Similarly, holes are made in the filter 5 in the remaining areas with lengths L ₁ , L ₃ .

In all the holes 4, 4 ', 4' ... 4 ⁿ set cut tube 6, 6 ', 6''... 6 ⁿ (3), for example, pressed cork cut 6, 6', 6 '' ... 6 ⁿ bottoms 7, 7 ′, 7 ′ ′ ... 7 ⁿ into the openings 4, 4 ′, 4 ′ ′ ... 4 ^{n of the} filter 5.

At the wellhead inside the filter 5 (Fig. 1), a shear funnel 8 is installed and fixed relative to the filter 5 with a shear element 9 relative to the filter 5, and from the outside - annular water swellable packers 10 ′, 10 ″. A production casing 11 with a filter 5 is lowered into a drilled horizontal well 2, and a filter 5 is installed in the well 2 so that the water swellable packers 10 ′, 10 ″ are at the boundaries of the zones of the formation 1 with different filtration-capacitive characteristics.

As annular water swellable packers 10 ′, 10 ′ ′, TAM FREECAP brand packers are used. These packers expand (swell), performing separation of layers after exposure to water on their cuff, while the volume expansion of the packer reaches 200%.

The use of annular water-swellable packers eliminates the alternate landing of packers by dropping locking elements from the wellhead into the well, as well as drilling cement plugs, packer seats and discharge elements, which makes it possible to simplify, accelerate, and cheapen the implementation of the method.

Landing of annular water-swellable packers occurs due to contact with water in horizontal injection wells, which eliminates the need to use dumping elements for landing packers and the likelihood of them being leaky on packer saddles, and this increases the reliability of the method.

Fix the production casing 11 (Fig. 1) in a horizontal well 2 by plugging 11 'and 11 ", in front of the filter 5 and behind it until the bottom 12, respectively. Leave the horizontal well 2 while waiting for the hardening of the grouting material, for example cement mortar, for 48 hours

The exclusion of cementing of filter 5 and the calculation of the selection of the area of the bore holes 4 of the filter 5 for each zone 3 ′, 3 ′ ′, 3 ″ ″ of the reservoir, depending on the permeability, improves the opening quality of the reservoir 1 and optimizes the injection of steam into the reservoir of high viscosity oil.

Then, at the mouth of the horizontal well 2, the assembly is assembled from the bottom up: a magnetic catcher 13, a pusher 14, a hard centralizer 15 with transfer channels 16 around the periphery. For example, the rigid centralizer 15 is equipped with four longitudinal ribs (not shown in FIGS. 1, 2, 3, 4) and, accordingly, four transfer channels 16 formed between the longitudinal ribs. The transfer channels 16 allow you to bypass the liquid through the hard centralizer 15 during the implementation of the method.

As a magnetic trap, a magnetic jet metal catcher (MSM) is used, manufactured by the Neftekamsk oil equipment plant (Russia, the Republic of Bashkortostan, Neftekamsk). MSM is designed to extract small metal objects from the bottom of oil and gas wells. High-energy magnets are used in MSM, the coercive force of which is almost 10 times higher than the strength of previously used magnets.

In the horizontal steam injection well 2, the layout on the pipe string 17 is lowered to the end of the pusher 14 in the end face 18 (Fig. 1) of the shear funnel 8.

Unload the pipe string 17 by 5 kN and destroy the shear element 9, fixing the shear funnel 8 relative to the production string 11. Under the influence of the weight of the pipe string 17, the shear funnel 8 is moved (Fig. 2) by means of the pusher 14 until it stops in the first row of shear plugs 6.

Then the pipe string 17 is completely (at its own weight) unloaded on a shear funnel 8 and the first row of shear plugs 6 is destroyed.

After the destruction of a number of cut off plugs 6, they are fixed on the surface of the magnetic trap 13 due to the attractive force of the magnet.

Then, under the influence of its own weight, the pipe string 17 is moved from the mouth to the bottom 12 and the next row of cut-off plugs 6 ′ is destroyed with their fixation on a magnetic catcher 13.

If during the destruction of a number of sheared plugs 6, 6 'the own weight of the pipe string 17 is not enough (i.e., when the pipe string 17 is completely unloaded, it does not move into the well) to destroy a row 8 of sheared plugs 6' with a shear funnel, then from the mouth of the steam injection horizontal well 2 in the pipe string 17 serves the process fluid, for example fresh water with a density of 1000 kg / m ³ and flush the horizontal well 2, for example in a double volume of the well, equal to 10 m ³ .

During the washing process, the process fluid rises at the wellhead 2 along the annulus 19, flowing around the periphery of the hard centralizer 15 through its transfer channels 16.

Flushing the well with a process fluid allows you to clean the well of dirt, sludge, a destroyed row of sheared plugs 6 ', preventing the destruction of a number of sheared plugs 6 "under the weight of the pipe string 17.

In addition, washing allows you to collect on the outer surface of the magnetic catcher 13 destroyed sheared plugs 6 '.

After washing, the pipe string 17 is again completely unloaded with the pusher 14 onto the shear funnel 8 and the remaining shear plugs 6 are destroyed over the entire cross section throughout the filter 5. The pipe string 17 with the assembly is removed to the surface.

A column of flexible pipes (not shown in FIGS. 1, 2, 3, 4) is lowered into the horizontal steam injection well 2 until the bottom 12, for example, with a diameter of 38.1 mm. Then the string of flexible pipes is moved from the bottom 12 (FIG. 2) to the mouth along the entire length of the filter 5, while at the same time a grouting composition is pumped through the flexible pipe, for example cement mortar 20 (FIG. 4), with which the holes 4 are insulated along the lower perimeter of the filter 21 .

Thus, in the horizontal well 2 (FIGS. 2 and 4), the lower perimeter 21 of the filter 5 is poured with cement mortar 20 along its entire length (L = 190 m). At the end of the waiting time for cement hardening, for example 24 hours, the filter 5 (Fig. 4) has openings 4 only along the upper perimeter 22 of the filter 5 along its entire length (L = 190 m).

The proposed method of installing a downhole filter in a horizontal steam injection well allows:

- to improve the quality of the opening of the reservoir by a horizontal well in high-viscosity oil deposits;

- increase the effectiveness of the impact of the working agent on the reservoir of high viscosity oil, regardless of the permeability of its rocks;

- reduce the duration of the destruction of the cut plugs.

Claims (1)

A method of installing a downhole filter in a horizontal injection well, including drilling a horizontal injection well, launching a production casing equipped with a downhole filter with shear plugs in the holes and packers, attaching a production casing in the well with a filter in the interval of the reservoir, and destroying shear plugs in filter holes, characterized in that in the process of drilling a horizontal well determine filtration-capacitive e characteristics, their change within the reservoir along the horizontal wellbore, divide the wellbore into zones that differ in filtration-capacitive characteristics by 1.5-1.6 times, and then select the area of the flow sections of the filter openings depending on the filtration-capacitive characteristics and the number of holes for each zone separately, make holes in separate sections of the filter and install cut-off plugs in them, then at the wellhead the filter inside is equipped with a cut-off funnel, fixed a shear element relative to the filter, and externally by annular water-swellable packers, a production casing with a filter is lowered into a drilled horizontal well and a filter is installed in the well so that the water-swell packers are at the boundaries of the formation zones with different filtration-capacitive characteristics, the production casing is fastened, then at the wellhead, the assembly is assembled from the bottom up: a magnetic catcher, a pusher, a hard centralizer with transfer channels along the periphery, are lowered the assembly on the pipe string into the well until the stop of the pusher in the shear funnel, unload the pipe string by 5 kN and destroy the shear element, move the shear funnel by the pusher until it stops in the first row of shear plugs, completely unload the sheath of pipe in the shear funnel and destroy the first row of shear plugs which, after destruction, are fixed on a magnetic catcher, then they move the pipe string from the mouth to the bottom and destroy the next row of cut-off plugs with their fixation on a magnetic catcher, by the weight of the pipe string or by pumping of biological fluid from the wellhead, followed by washing the well, after which the pipe string is completely unloaded again to the shear funnel and the remaining rows of shear plugs are destroyed along the entire filter cross-section, the pipe string with the layout is removed, then the flexible pipe string is lowered into the well before being drilled, it is moved from face to the mouth along the entire length of the filter and at the same time along the string of flexible pipes, grouting composition is injected, with which the holes made in the lower perimeter of the filter are isolated.

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