RU2564316C1 - Method of completion of horizontal production well construction with deposit interval hydraulic fracturing - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: during the method implementation the production casing is run and secured prior to the beginning of the well horizontal section, then the deposit interval hydraulic fracturing is performed in zones of the well bore that differ by the porosity and permeability characteristics by 1.5-1.6 times, in the well bore on the process pipes string the liner plugged at bottom and hydraulically disconnected, it has filters, between them the casing oil swelling packers are installed, at that number of the filters is equal to number of intervals of the deposit hydraulic fracturing, the casing oil swelling packers are installed with possibility of tight separation of intervals of the deposit hydraulic fracturing from each other during contact with oil. On the external surface of each filter the oil swelling filter in form of the elastic hose with holes is installed. At the contact with water the holes in the elastic hose shrink and tightly close from outside the holes in the filters. The process pipes string is disconnected from the plugged at bottom removable lining, the process pipes string is removed to the surface, pipes with pump are run in the horizontal well, and the horizontal well is put into operation.

EFFECT: increased efficiency and reliability of the method, simplified process, increased oil recovery of the production deposit.

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Description

The invention relates to the oil industry and can be used for opening productive formations by conducting interval hydraulic fracturing of the formation and equipment in these intervals with filters when completing well construction.

A known method of completing construction of a well (patent RU No. 2134341, IPC ЕВВ 43/11, published in Bulletin No. 33 of 08/10/1999), which includes launching a production casing with a filter in the drilled well equipped with plugs in the holes of the filter made of material, collapsing during chemical exposure, installing production casing in the well with a filter located in the interval of the reservoir, plugging the production casing with a filter, waiting for the hardening of grouting material, lowering into the well of the tubing string pipes, filling the well with a chemical reagent, holding the well for the duration of the destruction of 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. According to the invention, a chemical reagent-soluble material is added to the grouting material in the filter interval to break the plugs of the filter openings, before filling the well with a chemical reagent, fill the tubing cavity with gas at an open annulus at the wellhead and push the well fluid to the bottom of the tubing pipes, and after filling the well with a chemical reagent, it is pushed with gas into the annulus in the filter installation interval, after which the annulus the space 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 implementation of the method, due to the fact that when a water breakthrough in any interval of the filter is the flooding of all produced products;

- 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 soluble by the chemical agent are installed, was calculated without taking into account the reservoir properties of the reservoir, which means that in areas with high reservoir filter capacity will be limited, and in areas with low reservoir properties, on the contrary, will exceed the amount of oil withdrawal.

The closest in technical essence and the achieved result is a method of completing the construction of a producing horizontal well (patent RU No. 2516062, IPC ЕВВ 43/02, published May 20, 2014), which includes drilling a trunk of a producing horizontal well, lowering the production casing from the drilled well with a filter equipped with plugs in the holes from material that is destroyed by chemical exposure, installing a production casing in the well with a filter located in the interval of the reservoir, fixing the ion column, descent into the well of the pipe string, filling the well with a chemical reagent, holding the well for the time of destruction of the plugs in the holes of the filter. In the process of drilling a producing horizontal well, the reservoir characteristics of the formation and their change along the horizontal wellbore are determined, the wellbore is divided into zones that differ in reservoir characteristics by 1.5-1.6 times, depending on the reservoir characteristics the throughput of the filter holes for each zone and the number of holes, then mesh filter elements are installed in the filter holes under the plugs, the number of which corresponds to it depends on the number of holes in each zone, a production casing with a filter equipped with casing oil swell packers is lowered into a drilled horizontal production well, and they are installed at the boundaries of zones with different filtration-capacitive characteristics, the casing is secured, then the pipe string is lowered into the well and the chemical is pumped and fill it with a filter, hold the well for the duration of the destruction of the plugs in the holes of the filter and wash the reaction products, then lower a string of flexible pipes to the bottom of the well, it is moved from the bottom to the mouth with simultaneous injection of cement mortar through the string of flexible pipes, which fill the lower perimeter of the filter, a pipe string with a pump is lowered into a horizontal well and the horizontal well is put into operation.

The disadvantages of this method are:

- firstly, low efficiency due to the fact that when water breaks out from the formation into the horizontal wellbore in one or more zones of the filter, separated by annular oil swellable packers, all produced products are flooded in the horizontal wellbore;

- secondly, low reliability due to the fact that the holes in the filter before running into the well are equipped with plugs from material that is destroyed by chemical attack, and when the construction of the horizontal well is completed, chemical agent is pumped into the horizontal well bore and the filter is filled with it, the well is kept at the time of destruction of the plugs in the holes of the filter and the reaction products are washed out, while there is a high probability that the plugs will not be destroyed or partially destroyed due to dilution chemical reagent with well fluid, which significantly reduces the filter capacity, in addition, it is impossible to remove the filter for revision, since it is lowered into the cemented production string;

- thirdly, low oil recovery of the reservoir, since there is no work to intensify the flow of oil into the horizontal well bore when it is completed;

- fourthly, a complex and time-consuming technological process of its implementation, associated with the simultaneous descent of the production string, filter and casing oil swell packers into the horizontal wellbore, as well as the injection of a chemical reagent to dissolve the plugs in the holes and fill the lower perimeter of the filter with cement mortar.

The technical objectives of the proposal are to increase the efficiency and reliability of the implementation of the method, as well as increasing oil recovery of the reservoir, simplifying the process and reducing its complexity.

The stated technical problems are solved by the method of completing the construction of a producing horizontal well by conducting an interval hydraulic fracturing, including drilling a trunk of a producing horizontal well with determining the reservoir properties of the formation and their changes along the horizontal well, dividing the well into zones differing in the reservoir properties of the reservoir in 1.5-1.6 times, the selection of the throughput of the filter holes separately for each zone and the number of holes depending on the filtration-capacitive characteristics, the descent into the wellbore of a drilled horizontal well of the production string with a filter and casing oil swell packers, placement of packers at the boundaries of zones with different filtration-capacitive characteristics, fixing the production string, descent into the horizontal well of the pipe string with the pump and launch of a horizontal well into operation.

What is new is that the production casing is lowered and secured to the beginning of the horizontal section of the well, then the interval hydraulic fracturing is performed in the zones of the horizontal well bore, which differ in filtration-capacitive characteristics by 1.5-1.6 times, into the horizontal well on the production casing the pipes are lowered by a hydraulically separable, plugged down bottom shank equipped with filters, between which casing oil swell packers are installed, the number of filters p As the number of hydraulic fracturing intervals is performed, annular oil-swellable packers are installed in the horizontal wellbore with the possibility of tight separation of hydraulic fracturing intervals from each other in contact with oil, and on the outer surface of each filter there is a water-swellable packer made in the form of an elastic sleeve with holes and stretched over the filter, and the holes in the filters are aligned with the holes made in the elastic sleeves, and the diameters of the holes in the elasti The sleeve is made twice as large as the diameters of the holes in the filters and, upon contact with water, the holes in the elastic sleeve are pulled together and hermetically block the holes in the filters from the outside, the pipe string is disconnected from the removable liner plugged from below by triggering the borehole disconnector, and then the pipe string is removed to the surface, a pipe string with a pump is lowered into a horizontal well and a horizontal well is put into operation.

In FIG. 1 and 2 schematically depict the proposed method.

In FIG. 3 shows section AA.

In FIG. 4 shows a section BB.

The proposed method is as follows.

In the process of drilling a producing horizontal well, filtration-capacitive characteristics and their change within the reservoir 1 (see Fig. 1) are determined along the horizontal wellbore 2.

Divide the horizontal wellbore 2 into zones that differ in filtration-capacitive characteristics by 1.5-1.6 times.

For example, the length L of the horizontal wellbore 2 in the reservoir 1 is 420 m, the reservoir properties and their change along the horizontal wellbore 2 are divided into three zones as follows: zone 3 ′ - 1.0 Darcy permeability, length L ₁ = 120 m; zone 3 ″ - permeability of 1.55 Darcy, length L ₂ = 160 m (1.5 times relative to zone 3 ′); zone 3 ′ ′ ′ - permeability of 2.48 Darcy, length L ₃ = 140 m (1.6 times relative to zone 3 ″).

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

Then, the throughput (pass-through area) of the openings 4 ′, 4 ″, 4 ″ ″ (shown in Fig. 1, conditionally) of the corresponding filters 5 ′, 5 ″, 5 ″ ″ is selected, for example, for a filter with a diameter of 168 mm, separately for each zone 3 ′, 3 ″, 3 ″ ′ depending on the filtration-capacitive characteristics.

The selection of the area of the bore holes 4 ′, 4 ″, 4 ″ ″ of the corresponding filters 5 ′, 5 ″, 5 ″ ″ for each corresponding zone 3 ′, 3 ″, 3 ″ ″ is carried out in any known manner, for example, as described in patent RU No. 2134341, IPC ЕВВ 43/11, publ. in bull. No 33 on December 9, 1999

Filter 5 ', 5 ", 5"' is made of interconnected sleeves casing with an outside diameter D equal to 168 mm and an inner diameter D _vf equal to 140.3 mm. The cross-sectional area of the filter 5 F _to equal 154.5 cm ² .

Next, determine the number of holes 4 ′, 4 ″, 4 ″ ″ (see patent RU No. 2516062, IPC ЕВВ 43/02, publ. 05/20/2014), performed in the filter 5 ′, 5 ″, 5 ″ ″ in each zone, according to the formula:

N _zi = (K ₁ / K _i ) · (4 · F _k / π · d _o ² ) · L _i / k · а,

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

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

F _to - the cross-sectional area of the filter, cm;

π = 3.14;

d _o - diameter of the holes 4 ', 4 ", 4"' (.., see Figures 1 and 3) corresponding filters 5 ', 5 ", 5"', see d _o = 1,0 cm.

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

k is the coefficient of borehole ratio, taking into account that the selection of oil is carried out along the entire perimeter of the filters 5 ′, 5 ″, 5 ″ ′, k = 10;

and - the ratio of the rate of increase in flow rate after hydraulic fracturing is determined empirically, depending on the expected flow rate separately for each oil reservoir and is equal to from 2 to 5, we take a = 3.

Interval hydraulic fracturing after drilling a horizontal wellbore allows a multiple increase in the oil recovery of a productive formation when a horizontal well is put into operation after it is completed with construction, in addition, oil flows into the open well of a horizontal well, rather than cased, as described in the prototype.

Thus, substituting the values in the formula, we get the number of holes made in the filter 5 in each separate zone, taking into account the coefficient of the rate of increase in flow rate after hydraulic fracturing:

N _Z1 = (1.0 / 1.0) · (4 · 154.5 / 3.14 · 1.0 ² ) 120/10 · 3 = 7085 pcs.

N _Z2 = (1.0 / 1.55) · (4 · 154.5 / 3.14 · 1.0 ² ) 160/10 · 3 = 6093 pcs.

N _Z3 = (1.0 / 2.48) · (4 · 154.5 / 3.14 · 1.0 ² ) 140/5 · 3 = 3306 pcs.

The distance between the holes 4 ′ along the length of the filter 5 ′ and 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 = 6093 pcs. perform a radial row of 4 ″ openings, for example, eight openings with a diameter of 10 mm around the perimeter of the filter 5 ″ and at a distance of 0.21 m between the rows of radial openings 4 ″, i.e. (160 m / 6093 pcs.) · 8 = 0.21 m.

Similarly, holes 4 ′ and 4 ″ ″ are made in the corresponding filters 5 ′ and 5 ″ ″ in the remaining zones 3 ′ and 3 ″ ″ with lengths L ₁ and L _3, respectively.

The production casing 6 is lowered and secured to the beginning of the horizontal section 6 ′ of the well 2.

In the proposed method, in contrast to the prototype, the openings in the filters are not equipped with plugs from a material that collapses during subsequent chemical exposure before they are lowered into a horizontal well, due to the filter being lowered into the open hole of a horizontal well as a part of a pipe string and not as part of a cemented one production casing. This allows you to increase the reliability of the implementation of the method by eliminating the risk of loss of filter capacity due to incomplete destruction of the plugs in the holes of the filters.

Interval hydraulic fracturing of formation 1 is performed with formation of cracks 7 ′, 7 ″, 7 ″ ″ respectively in zones 3 ′, 3 ″, 3 ″ ″ with the corresponding length L ₁ , L ₂ , L ₃ in the horizontal well bore 2. Interval hydraulic fracturing the formation is produced by any known method, for example, according to the method of multiple hydraulic fracturing in a horizontal wellbore (patent RU No. 2472926, IPC EV 43/267, publ. 01.20.2013) or the method of multiple hydraulic fracturing in a horizontal wellbore (patent RU No. 2515651, IPC Е21В 43 / 267, publ. 05.20.2014).

In the horizontal wellbore 2 on the column of process pipes 8 (not shown in FIGS. 1 and 2), a hydraulically disconnected by means of a borehole disconnector 8 ′ of any known construction is lowered, for example, patent RU No. 2439281, IPC ЕВВ 17/06, publ. 01/10/2012 or patent RU No. 2444607, IPC ЕВВ 17/06, publ. 03/10/2012, an extractable shank 9 plugged from below, equipped with filters 5 ′, 5 ″, 5 ″ ″, between which casing oil swellable packers 10 ′, 10 ″, 10 ″ ″ are installed. The number of filters 5 ′, 5 ″, 5 ″ ″ is equal to the number of fractures 7 ′, 7 ″, 7 ″ ″ in the horizontal wellbore, in which hydraulic fracturing of the formation 1 was performed. Filters 5 ′, 5 ″, 5 ″ ″ were lowered as part of the plugged from the bottom of the retractable shank 9, which allows, if necessary, using a fishing tool to remove the shank from the bottom 9, which is muffled from below, for revising the filters 5 ′, 5 ″, 5 ″.

The annular oil swellable packers 10 ′, 10 ″, 10 ″ ″ (see FIGS. 1 and 2) are installed in the 2 ″ well of the horizontal well 2 so that they have the possibility of tight separation of the hydraulic fracturing intervals, i.e. cracks 7 ′, 7 ″, 7 ′ ″ apart. On the outer surface of the filters 5 ′, 5 ″, 5 ″ ″, the corresponding water swellable packers 11 ′, 11 ″, 11 ″ ″ are installed.

Water swellable packers are made in the form of an elastic sleeve 11 ′, 11 ″, 11 ″ ″ with openings 12 ′, 12 ″, 12 ″ ″ and stretched to the corresponding filters 5 ′, 5 ″, 5 ″ ″.

The holes 4 ′, 4 ″, 4 ″ ″ in the filters 5 ′, 5 ″, 5 ″ ″ are aligned with the holes 12 ′, 12 ″, 12 ″ ″ made in the elastic sleeve 11 ′, 11 ″, 11 ″ ″.

The diameters of the holes 12 ′, 12 ″, 12 ″ ″ in the elastic sleeve 11 ′, 11 ″, 11 ″ ″ are twice the diameters of the holes 4 ′, 4 ″, 4 ″ ″ in the filters 5 ′, 5 ″, 5 ″ ″.

As casing oil swellable packers 10 ′, 10 ″, 10 ″ ″ and water swellable packers made in the form of an elastic sleeve 11 ′, 11 ″, 11 ″ ″, for example, FREECAP brand packers are used.

The annular oil swellable packers 10 ′, 10 ″, 10 ″ ″ expand (swell), causing the separation of zones 3 ′, 3 ″, 3 ″ ″ of the horizontal wellbore after the oil is exposed to their cuff.

Compared with the prototype, the process of implementing the method is simplified and its complexity is reduced due to the fact that the filters are lowered at the end of the pipe string with the pump and can be removed, while the technological operations of pumping a chemical reagent to dissolve the plugs in the holes and filling the lower perimeter of the filter with cement are excluded solution.

The technological string of pipes 8 is disconnected from the retractable liner 9 muffled from below by activating the downhole disconnector 8 ′, after which the technological string of pipes 8 is removed to the surface, and the liner 9 remains in the horizontal wellbore 2.

Lowered into a horizontal well 2 (see Fig. 2) a pipe string 13 with a pump 14.

By turning on the pump 14, a horizontal well 2 is launched into operation, while the influx of oil into the well of the horizontal well 2 begins. Upon contact with the oil, the cuffs of the annular oil swellable packers 10 ′, 10 ″, 10 ″ ″ swell, which leads to a tight separation of the hydraulic fracturing intervals, those. cracks 7 ′, 7 ″, 7 ″ ′ apart.

During the operation of horizontal well 2, oil from reservoir 1, including from intervals of hydraulic fracturing, i.e. from the cracks 7 ′, 7 ″, 7 ″ ″ (see FIGS. 1 and 3) enters the horizontal well 2 and then through the holes 12 ′, 12 ″, 12 ″ ″ in the elastic sleeve 11 ′, 11 ″, 11 ″ ′ And openings 4 ′, 4 ″, 4 ″ ″ in the filters 5 ′, 5 ″, 5 ″ ″ enter the horizontal well bore 2 separately from each of the hydraulic fracturing intervals, i.e. from cracks 7 ′, 7 ″, 7 ″ ′. From where the pump 14 through the string of pipes 13 pump oil to the surface.

Also, in the process of operating a horizontal well 2, a breakthrough of water into the well of a horizontal well 2 is possible in any interval of opening of a productive formation 1 by a horizontal well 2, including through intervals of hydraulic fracturing, i.e. cracks 7 ′, 7 ″, 7 ″ ′. For example, a water breakthrough in the horizontal wellbore 2 occurred in the interval of hydraulic fracturing, i.e. crack 7 ″. Oil from reservoir 1 through cracks 7 ′ and 7 ″ ″ (see FIGS. 2 and 4) enters the horizontal wellbore 2 and then through the holes 12 ′, 12 ″ ″ in the elastic sleeve 11 ′ and 11 ″ ″ enters the horizontal wellbore wells 2 separately from each interval of hydraulic fracturing, i.e. from the cracks 7 ′, 7 ″ ″, and water from the aquifer 15, separated from the reservoir 1 by a layer (clay) along the 7 ″ fracture, enters the horizontal well 2 and then enters the holes 12 ″ of the elastic sleeve 11 ″, while there is a volume expansion of the water swellable packer (11 ″ elastic sleeve) and the 4 ″ holes in the 5 ″ filter into which water enters are hermetically sealed from the outside by tightening the 12 ″ holes in the 11 ″ elastic sleeve. Thus, the cut-off of zone 3 ″ of the horizontal wellbore 2, watering the oil, occurs.

Due to the presence of water swellable packers made in the form of elastic sleeves 11 ′, 11 ″, 11 ″ ″ with openings 12 ′, 12 ″, 12 ″ ″, the efficiency of the method is increased due to the fact that at the beginning of flooding of products in any of the zones 3 ′, 3 ″, 3 ″ ”of the horizontal well bore 2, this zone is cut off, which ensures a long anhydrous period of horizontal well 2 operation.

The diameters of the holes 12 ′, 12 ″, 12 ″ ″ - D (see Figs. 3 and 4) in the elastic sleeve 11 ′, 11 ″, 11 ″ ″ are twice as large as the diameters of the holes 4 ′, 4 ″, 4 ″ ″ - d filters 5 ′, 5 ″, 5 ″ ″, since the volumetric expansion of the elastic sleeve reaches 200%, which ensures narrowing of the holes 12 ′, 12 ″, 12 ″ ″ in the elastic sleeve 11 ′, 11 ″, 11 ″ ’to a tight overlap outside the holes 4 ′, 4 ″, 4 ″ ′ in the filters 5 ′, 5 ″, 5 ″ ′.

The proposed method for completing the construction of a producing horizontal well with an interval hydraulic fracturing allows to increase the efficiency and reliability of the implementation of the method, as well as to increase the oil recovery of the productive reservoir by conducting an interval hydraulic fracturing in an open hole of a horizontal well, as well as to simplify the process and reduce its complexity.

Claims (1)

A method of completing the construction of a producing horizontal well by conducting an interval hydraulic fracturing, including drilling a trunk of a producing horizontal well with determining the reservoir properties of the formation and changing them in the horizontal well, dividing the well into zones differing in reservoir properties of 1.5- 1.6 times, selection of the throughput of the filter holes for each zone and the number of holes depending on the filter ion-capacitive characteristics, launching a production casing with a filter and casing oil swell packers into the wellbore of a horizontal well drilled, placing packers at the boundaries of zones with different filtration-capacitive characteristics, securing a production casing, launching a pipe string with a pump into a horizontal well and putting a horizontal well into operation characterized in that that the production casing is lowered and secured to the beginning of the horizontal section of the well, then interval hydraulic fracturing is performed in the zones of the horizontal well bore, which differ in filtration-capacitive characteristics by 1.5-1.6 times, the hydraulically disconnected into the horizontal well on the casing string is lowered a retractable shank plugged from below equipped with filters, between which casing oil swell packers are installed, and the number of filters is equal to the number of in of hydraulic fracturing intervals, an annular oil-swelling packer is installed in the horizontal wellbore with the possibility of tight separation of the hydraulic fracturing intervals from each other in contact with oil, and on the outer surface of each filter there is a water-swelling packer made in the form of an elastic sleeve with holes and stretched over filter, and the holes in the filters are aligned with the holes made in the elastic sleeves, and the diameters of the holes in the elastic sleeve are made They are twice as large as the diameters of the openings in the filters and, when in contact with water, the openings in the elastic sleeve are pulled together and hermetically shut off the openings in the filters from the outside, disconnect the pipe string from the retrievable plug plugged from below by actuating the borehole disconnector, and then remove the pipe string to the surface , a pipe string with a pump is lowered into a horizontal well and a horizontal well is put into operation.

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