RU2514040C1 - Method of fitting well filter in horizontal well - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: in drilling, seepage-volume characteristics of the bed and their alteration over borehole are defined, borehole is divided into zones that differ in said characteristics by 1.5-1.6 times to select filter performance separately for each zone and quantity of holes. Screen filter elements are fitted in filter holes under plugs. Flow string with filter equipped with water- or oil-swelling packers is lowered into well, said packers being set at boundaries of zones with different characteristics and string being fixed. Assembly is assembled at mouth and composed of the following elements arranged from bottom to top, i.e. cutter, locating bearing, screw downhole motor and stiff locator to be lowered against the stop to plugs. At cutting sheared plugs, flow string is displaced downward to remove sheared plugs and to withdraw the flow string. Flexible pipe sting is lowered to work face and displaced therefrom to mouth along with injection of plugging material to isolate holes made at filter bottom perimeter.

EFFECT: higher efficiency of extraction or injection, simplified mounting.

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Description

The invention relates to the field of development of highly viscous oil fields and can be used for opening productive formations with horizontal producing or injection wells and equipping them with filters in this interval.

A known method of completing the construction of a well (patent RU No. 2134341, IPC ЕВВ 43/11, published on 08/10/1999), including the descent of a production casing with a filter equipped with plugs in the holes of a material that is destroyed by chemical exposure, installation of production columns in the well with a filter in the interval of the reservoir, plugging the production string with a filter, waiting for the solidification of the cement material, lowering the tubing string into the well, filling in Azhinov 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. According to the invention, a material soluble with a chemical reagent to break the plugs of the filter openings is added to the grouting material in the filter range. Before filling the well with a chemical reagent, the tubing cavity is filled with gas in the annulus at the wellhead and the well fluid is pushed to the bottom of the tubing, and after filling the well with 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 a compressor.

The disadvantages of this method are:

- firstly, the low quality of the opening of the reservoir, due to the fact that they are plugging both production casing and the filter, while behind the filter a cement stone is formed, worsening 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 through the filter body into which the plugs dissolving under the influence of a chemical reagent are installed does 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 capacity will be limited, and in areas with low reservoir properties of the reservoir, on the contrary, will exceed the sampling volume high viscosity oil.

Also known is a method of completing construction of a well (AS SU No. 1210507, IPC ЕВВ 43/08, published December 12, 1987), which includes launching a production casing equipped with a filter with plugs in holes made of material that is destroyed by chemical impact, 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, filling wells with a chemical reagent, holding the well for the time of destroying the plugs of the filter openings, injecting gas with variable pressure until the injected gas is connected to the formation fluid and cleaning the well from reaction products.

The disadvantages of this method are:

- 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 does 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, will exceed the injection volumes or selection of high viscosity oil from this zone.

The closest in technical essence is the method of installing a well filter (patent RU No. 2378495, IPC ЕВВ 43/08, published on January 10, 2010, bull. No. 1), including drilling a wellbore, launching at least one wellbore into a drilled well a filter installed in the production casing containing cut-off plugs in the holes of the filter; in this case, a centralizer is installed on each well filter before being lowered into the well, which is fixed on the downhole filter pipe, which is free of the filter element, above the well filter columns are installed, the number of which corresponds to the number of productive formations, after the casing string is lowered, the well is washed and the packers are activated alternately from the bottom up, 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 pumping cement into the annulus space for mounting the production string above the reservoir. After the cement has hardened, cementing plugs, packer seats and waste elements are drilled, and all filter plugs are cut.

The disadvantages of this method are:

- firstly, the complexity of the process associated with the alternate landing 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 pumping 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 packer seats with a discharge element, for example, a ball, and in horizontal wells there is a high probability of leakage of the discharge element on the packer saddle;

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

The technical tasks of the invention are to increase the reliability and efficiency of opening a productive formation by a horizontal well in high-viscosity oil fields, taking into account the reservoir properties of the formation, as well as simplifying the process of installing a well filter in a horizontal well.

The tasks are solved by installing a downhole filter in a horizontal well, including drilling a horizontal wellbore, lowering a production casing equipped with a downhole filter with cut-off plugs in holes and packers, attaching a production casing in the well with a filter in the interval of the producing formation, and removing cut-off traffic jams in openings of the filter.

New is that in the process of drilling a producing or injection horizontal well, the reservoir properties of the formation and their change in the horizontal well are determined, the wellbore is divided into zones that differ in filtration and capacitive characteristics by 1.5-1.6 times, depending on the filtration-capacitive characteristics, the filter capacity of the filter holes for each zone and the number of holes are selected, then mesh filtering filters are installed in the filter holes under the plugs elements, the number of which corresponds to the number of holes in each zone, lower the production casing with a filter equipped with casing water or oil swell packers into the drilled horizontal well, and install them at the boundaries of zones with different filtration-capacitive characteristics, fix the production casing, then at the wellhead assemble the layout from bottom to top: milling cutter, centralizer bearing, downhole helical motor, rigid centralizer, lower the layout on the pipe string to the stop in the cut-off plugs, the process fluid is fed into the pipe string and, using the screw downhole motor, the cutter is rotated, during the milling of the cut-off plugs the pipe string is downward and the cut-off filter plugs are removed over its entire cross-section, the pipe string with the layout from the well is removed, then the bottom of the bottom of the string of flexible pipes, move it from the bottom to the mouth with the simultaneous injection of grouting composition along the string of flexible pipes, which isolate the holes made in the lower perimeter of the filter.

In figures 1, 2, 3 schematically shows a method of installing a downhole filter in a horizontal well.

The proposed method is as follows.

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

For example, the length L of the horizontal wellbore 2 in the reservoir 1 is 400 m, the reservoir properties and their change along the horizontal wellbore 2 are defined as follows:

zone 3 '- permeability of 0.85 Darcy, length L ₁ = 120 m;

zone 3 "- permeability of 1.3 Darcy, length L ₂ = 80 m (1.53 times relative to zone 3 ');

zone 3 '"- permeability 2.0 Darcy, length L ₃ = 60 m (1.54 times relative to zone 3");

zone 3 "" - permeability 3.2 Darcy, length L ₄ = 140 m (1.6 times relative to zone 3 '").

The boundaries of the zones 3 ', 3 ", 3'", 3 "" are the boundaries of lengths L ₁ , L ₂ , L ₃ , L ₄ , where the filtration-capacitive characteristics differ by 1.5-1.6 times.

Then, the throughput (pass-through area) of the holes 4, 4 ', 4 "... 4 ⁿ (shown in Fig. 1 conditionally) of the filter 5 is selected, for example, for a filter with a diameter of 168 mm for each zone 3', 3", 3 '",3""select the area of the bore openings depending on the filtration and capacitive characteristics. Selection of the area of the bore openings 4, 4 ', 4" ... 4 ⁿ filter 5 for each zone 3', 3 ", 3 '", 3 ""carried out by any known method, for example, as described in patent RU No. 2134341, IPC EV 43/11, publ. in bull. No 33 on December 9, 1999

The filter 5 is made of casing with an outer diameter D equal to 168 mm and an inner diameter Dvf equal to 140.3 mm. The cross-sectional area of the 5 Fc filter is 154.5 cm ² .

Next, determine the number of holes 4; four'; 4 "... 4 ⁿ , performed in the filter 5 in each zone, according to the formula:

N _Zi = (K ₁ / Ki) - (4 · Fк / П · do ² ) · L _i / k,

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

Ki is the permeability of the rocks in the zone of the productive part, opened by the horizontal wellbore, Darcy;

Fк - filter cross-sectional area, cm ² ;

P = 3.14;

do - the bore diameter of the cut-off plugs 6, 6 ', 6 "... 6 ⁿ (conventionally shown in Fig. 2) inserted into the holes 4, 4', 4" ... 4 ⁿ (see Fig. 1) of the filter 5, cm, take do equal to 1.2 cm;

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

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 equal to 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 ) 120/5 = 3281 pcs.

N _Z2 = (0.85 / 1.3) · (4 · 154.5 / 3.14 · 1.2 ² ) 80/5 = 1430 pcs.

N _Z3 = (0.85 / 2.0) · (4 · 154.5 / 3.14 · 1.2 ² ) 60/5 = 697 pcs.

N _Z4 = (0.85 / 3.2) · (4 · 154.5 / 3.14 · 1.2 ² ) 140/5 = 1016 pcs.

The distance between the holes along the length of the filter 5 and the number of holes 4, 4 ', 4 "... 4 ⁿ along the perimeter of the filter is determined by calculation.

For example, for a zone of length L ₂ with the number of holes N _Z2 1430 pcs. perform a radial row of holes, for example 8 holes with a diameter of 20 mm around the perimeter of the filter 5 and at a distance of 0.45 m between the rows of radial holes, i.e. (80 m / 1430) · 8 = 0.45 m. Similarly, holes are made in the filter 5 in the remaining areas with lengths L ₁ , L ₃ , L ₄ .

All openings 4, 4 ', 4 "... 4 ^{n of} filter 5 are equipped with cut-off plugs 6, 6', 6" ... 6 ⁿ (conventionally shown in FIG. 2), i.e. install cutoff plugs 6, 6 'into holes 4; 6 "... 6 ⁿ , for example, cut-off plugs 6, 6 ', 6" ... 6 ⁿ bottoms inward (see FIG. 2) are pressed into the holes 4, 4', 4 "... 4 ^{n of the} filter 5. Cut-off plugs 6, 6 ' , 6 "... 6 ^{n is} made of steel 35.

Then, in the openings 4, 4 ', 4 "... 4 ⁿ (conditionally shown in Figs. 1 and 2) of the filter 5 under the cut-off plugs 6, 6', 6" ... 6 ⁿ , mesh filter elements 7 are installed (Fig. 2 is shown conditionally ), the number of which corresponds to the number of holes 4, 4 ', 4 "... 4 ⁿ in the zones 3', 3", 3 "', 3"".

The production casing 8 with a filter 5, equipped with casing oil or water swellable packers 9 ', 9 ", 9'" ... 9 ^n, respectively, is lowered into the drilled shaft of the producing or injection horizontal well 2 (Fig. 1), and they are installed at the boundaries of zones 3 ' , 3 ", 3 '", 3 "" of the reservoir 1. For example, three packers 9', 9 ", 9 '" are installed in zones 3', 3 ", 3 '", 3 "".

As annular oil or water swellable packers, for example, TAM brand FREECAP packers are used. These packers expand (swell), causing formation separation after exposure to high viscosity oil or water on their cuff, while the volume expansion of the packer reaches 200%.

The mesh filter elements 7 (see FIG. 2) are, for example, made of porous metal fiber material (PMF) and porous sintered material (SL) made of 316L stainless steel or an alloy with a high nickel content, which allows them to withstand the most severe operating conditions in a horizontal production well. The mesh filter element 7 provides reliable and durable prevention of sand removal.

The use of casing oil or water-swellable packers eliminates the alternate landing of packers by dropping shut-off elements from the wellhead into the well, as well as drilling cement plugs, packer seats and dump elements, which makes it possible to simplify, speed up, and cheapen the implementation of the method.

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

Fix the production casing 8 (see Fig. 1) in horizontal well 2 by cementing 8 'and 8 ", in front of the filter 5 and behind it, respectively. Leave the horizontal well 2 while waiting for hardening, for example, cement mortar for 48 hours

The calculation of the throughput of the filter 5, i.e. the cross-sectional areas of the openings 4, 4 ', 4 "... 4 ^{n of the} filter 5, depending on the filtration-capacitive characteristics of each zone 3', 3", 3 '", 3""of the reservoir, opposite which the filter 5 is installed, improves the quality of opening reservoir 1.

At the mouth of the horizontal well 2, the assembly is assembled from the bottom up: a mill 10, a centralizer bearing 11, a downhole screw motor 12, a hard centralizer 13, It is lowered into a horizontal well 2 on a pipe string 14 until the mill 10 interacts with the cut-off plugs 6 (in Fig. 1 shown schematically).

As a downhole screw motor 12, for example, an engine of the brand D3-106MP.7 / 8.37 is used.

The process fluid is pumped, for example, fresh water with a density of 1000 kg / m ³ , into the pipe string 14 using a pump unit, for example, CA-320. Under hydraulic pressure of the process fluid in the pipe string 14, a screw downhole motor 12 is driven, which transmits rotation to the cutter 10. Thus, the cut-off plugs 6 are removed by milling over the entire cross section of the filter 5. Next, the pipe string 14 with the layout is removed.

A string of flexible pipes is lowered into the horizontal well 2 until the bottom 15 (a flexible pipe is unwound on the installation drum) (not shown in Figs. 1 and 2, 3), for example, with a diameter of 38.1 mm.

Then the column of flexible pipes is moved (wound on the drum of the installation with a flexible pipe) from the bottom 15 to the mouth along the entire length of the filter 2 (see Fig. 1) with the simultaneous injection of grouting composition, for example cement mortar 16 (see Fig. 3), a flexible pipe for isolating the holes 4 '(see figure 1), made in the lower perimeter of the filter 5.

Thus, in the horizontal well 2, the lower perimeter of the filter 5 is poured with cement mortar 16 along its entire length (L = 400 m). At the end of the waiting time for the cement to harden, for example 24 hours, the filter 5 (see FIG. 3) has openings 4 only along the upper perimeter of the filter 5 along its entire length (L = 400 m).

The method of installing a downhole filter in a horizontal well allows you to:

- increase the efficiency of the selection of highly viscous oil from a horizontal producing well or steam injection into a horizontal injection well;

- to improve the quality of the opening of the reservoir by taking or injecting steam only through the upper perimeter of the filter, taking into account the reservoir properties of the reservoir;

- to simplify the process of installing a downhole filter in a horizontal production or injection well.

Claims (1)

A method of installing a downhole filter in a horizontal well, including drilling a horizontal wellbore, launching a production string equipped with a downhole filter with shear plugs in the holes and packers, attaching the production string in the well with a filter in the interval of the reservoir, removing shear plugs in the holes filter, characterized in that in the process of drilling a producing or injection horizontal well determine filtration-capacitive characteristics reservoir characteristics and their change along the horizontal wellbore, divide the wellbore into zones that differ in filtering and capacitive characteristics by 1.5-1.6 times, depending on the filtering and capacitive characteristics select the filtering capacity of the filter holes for each zone and the number holes, then mesh filter elements are installed in the holes of the filter under the plugs, the number of which corresponds to the number of holes in each zone, lowered into a drilled horizontal well a production casing with a filter equipped with annular water- or oil-swelling packers, and they are installed at the boundaries of zones with different filtration-capacitive characteristics, the production casing is fastened, then the assembly is assembled from the bottom to the top of the well: cutter, centralizer bearing, downhole screw motor, rigid centralizer, lowering the layout on the pipe string to the stop in the cut-off plugs, supplying the process fluid to the pipe string and, by means of a downhole screw motor, milling cutter, during the milling of the cut-off plugs, the pipe string is moved down and the cut-off plugs of the filter are removed over its entire cross-section, the pipe string with the layout is removed from the well, then the flexible pipe string is lowered to the bottom, it is moved from the bottom to the mouth with the grouting composition being pumped along a column of flexible pipes, which isolate the holes made in the lower perimeter of the filter.

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