RU2516062C1 - Construction finishing method for horizontal producer - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: in drilling, seepage-volume characteristics of the bed and their alteration over the borehole are defined, the borehole is divided into zones that differ in said characteristics by 1.5-1.6 times to select the filter performance separately for each zone and quantity of holes. In the filter openings under the plugs mesh filtering elements are installed, the production string is run in with the filter equipped with the behind-the-casing oil-swellable packers, which are set at boundaries of the areas with different seepage-volume characteristics. The production string is set up, then the pipe string is run in into the well and a chemical agent is injected filling the filter, the well is hold for the time of the plugs destruction in the filter openings and then reaction products are washed out. A coil tubing is run in up to the well bottom, then it is transferred from the well bottom to the head with simultaneous pumping of cement slurry through it thus pouring the lower perimeter of the filter.

EFFECT: improving quality of the productive stratum penetration.

3 dwg

Description

The invention relates to the field of development of high-viscosity oil deposits and can be used for opening productive formations and their equipment when completing the construction of producing horizontal wells, namely, when the injection horizontal well is located under the horizontal producing well.

A known method of installing a downhole filter (patent RU No. 2378495, IPC E21B 43/08, published in Bulletin No. 1 of January 10, 2010), comprising lowering into the drilled well at least one downhole filter installed at the bottom of the casing and containing cut-off plugs; in this case, a centralizer is installed on each well filter before being lowered into the well, which is fixed on the well filter pipe that is free of the filter element, packers are installed above the well filters, the number of which corresponds to the number of reservoirs, after as a casing string, the well is washed and packers are activated alternately from bottom to top, closing the central holes in the packer seats with a discharge element, for example, a ball, followed by pressure increase inside the casing and pumping cement into the annulus above the reservoir. After the cement has hardened, cementing plugs, packer seats and dumping elements are drilled, and all filter plugs are cut off, while downhole filters are installed below the liner, which is connected through a disconnecting device to the transport string to deliver well filters in the liner structure, and after installation downhole filters with a liner in place of the transport string is undocked and removed from the well, and below the downhole filters set the inverse to lapan and shoe.

The disadvantages of this method are:

-first, a complex and labor-intensive technological process of its implementation;

secondly, the long duration of the method, associated with the need to lower additional equipment into the well to destroy shear plugs, it is possible that part of the shear plugs will remain intact;

thirdly, inefficient opening of the reservoir, since the number of shear plugs installed on the filter body does not take into account the permeability of the zones of the productive part of the well, opposite which this filter is located, which means that in areas with high permeability the filter capacity will be limited , and in zones with low permeability, on the contrary, it will exceed the volume of high-viscosity oil withdrawal.

The closest in technical essence is the method of completing well construction (patent RU No. 2134341, IPC E21B 43/11, published in Bulletin No. 33 of 08/10/1999), including the descent of a production casing with a filter equipped with plugs into the drilled well openings of a filter made of a material that is destroyed by chemical attack, installing a production casing in a well with a filter located in the interval of the reservoir, plugging a production casing with a filter, waiting for the grouting material to solidify, running column wellbore tubing, filling the well with a chemical reagent to extract borehole decay time filter plugs holes, gas injection with variable pressure to the pressurization gas compounds with the formation fluid and cleaning the well from the 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 plug both the production string 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 soluble by the chemical agent are installed does not take into account the reservoir properties of the reservoir, which means that in areas with high filtration - the capacitance characteristics of the reservoir, the filter capacity will be limited, and in areas with low filtration and capacitance characteristics of the reservoir, on the contrary, will exceed the volume of selection of highly viscous oil.

The technical objectives of the proposal are to improve the quality of the opening of a productive formation by a producing horizontal well in a highly viscous oil reservoir and to increase the efficiency of the selection of highly viscous oil from a reservoir with various filtration-capacitive characteristics of the reservoir by ensuring optimal inflow and alignment of the profile of the inflow of highly viscous oil.

The tasks are solved by the method of completing the construction of a producing horizontal well, including drilling a trunk of a producing horizontal well, lowering a production casing with a filter into the drilled borehole, equipped with plugs 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 production string, lowering the pipe string into the well, filling the well with a chemical reagent , shutter speed at the time of destruction of the plugs in the holes of the filter.

New is that in the process of drilling a producing horizontal well, the reservoir properties of the formation and their change along the horizontal well’s bore are determined, the wellbore is divided into zones that differ in reservoir properties by 1.5-1.6 times, depending on filtering capacity characteristics select the filtering capacity 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 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 production casing is fastened, then the pipe string is lowered into the well and pumped chemical reagent and fill it with a filter, withstand the well for the time of destruction of plugs in the holes of the filter and wash products p reactions, then lower the string of flexible pipes to the bottom of the well, make it move from the bottom to the wellhead with the simultaneous injection of cement mortar through the string of flexible pipes, which fill the lower perimeter of the filter.

Figure 1, 2, 3 schematically shows the proposed method.

The proposed method is carried out on deposits of highly viscous oil with the location of the injection horizontal well above the producing horizontal well.

The proposed method is as follows.

In the process of drilling a producing horizontal well, filtration-capacitive characteristics are determined and their change within the reservoir 1 (see Fig. 1) along the horizontal wellbore 2. Divide the wellbore into zones that differ in filtration-capacitive characteristics of 1.5-1 , 6 times.

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

zone 3'- permeability 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 , 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 ”... 4” (shown in Fig. 1 conditionally) of the filter 5 is selected, for example, for a filter with a diameter of 168 mm, separately for each zone 3', 3 ”, 3 ' '', 3 ”” depending on the filtration-capacitive characteristics.

The selection of the area of the bore holes 4, 4 ', 4 ”... 4” of the filter 5 for each zone 3', 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 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, 4 ', 4 ”... 4”, performed in the filter 5 in each zone, according to the formula:

N _zi = (K ₁ / Ki) · (4 · Fк / 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, Darcy;

Ki - permeability of rocks in the zone of the productive part, opened by a horizontal well, Darcy;

Fк - filter cross-sectional area, cm;

π = 3.14;

do - the bore diameter of plugs 6, 6 ', 6 m ... 6 ”(shown in figure 2 conventionally) inserted into the holes 4, 4', 4” ... 4 ”(see figure 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 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 12 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 the} filter 5 are equipped with plugs 6, 6', 6” ... 6 ”(see figure 2, shown conventionally), destroyed (soluble) by a chemical reagent (for example, hydrochloric acid).

For example, plugs 6, 6 ', 6 ”... 6 ^{n are} pressed into the corresponding holes 4, 4', 4” ... 4 ^{n of the} filter 5, and plugs made of magnesium alloy are used as plugs as described in patent RU No. 2397316, IPC E21B 43/11, publ. 08/20/2010, bull. Number 23.

Then, in the openings 4, 4 ', 4 ”... 4 ⁿ (conditionally shown in FIGS. 1 and 2) of the filter 5, mesh filter elements 7 are installed under the plugs 6, the number of which corresponds to the number of openings 4, 4', 4” ... 4 ⁿ in zones 3 ', 3 ”, 3''', 3” ”.

Lowered into the drilled production horizontal well 2 (Fig. 1), production casing 8 with a filter 5, equipped with casing oil swell packers 9 ', 9 ", 9''' ... 9 ⁿ and set them at the boundaries of zones 3 ', 3”, 3''', 3 ”” of the reservoir 1. For example, zones 3 ', 3 ”, 3''', 3” ”are equipped with three packers 9 ', 9”, 9'''.

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

The mesh filter elements 7 (see FIGS. 2 and 3) are made, for example, 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 toughest operating conditions in a horizontal production well. The mesh filter element 7 provides reliable and durable prevention of sand removal.

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

The elimination of cementing of filter 5 and the calculation of the area of the bore holes 4 of filter 5 for each zone 3 ', 3 ”, 3' '', 3” ”of the reservoir, depending on the permeability, improves the opening quality of the reservoir 1 and optimizes the selection of highly viscous oil from the reservoir .

Next, a pipe string is lowered into the well 1 (not shown in FIGS. 1 and 2) and a chemical reagent is pumped through it, for example, a 15% aqueous solution of hydrochloric acid 10 (FIG. 2). Filter 5 is filled over the entire cross section over its entire length (L = 400 m) with a 15% aqueous hydrochloric acid solution, for example, in a filter volume of 7 m ³ .

The well 1 is maintained during the reaction of hydrochloric acid with a magnesium alloy, i.e. to destroy the plugs 6 (see FIG. 3) in the holes 4 of the filter 5, for example, for 8 hours. At the end of this time, the reaction products of a 15% aqueous hydrochloric acid solution with soluble plugs 6 are washed out of the filter 5, for example, by injection fresh water with a density of 1000 kg / m ³ with circulation until the reaction products yield a 15% aqueous hydrochloric acid solution. As a result, the filter 5 (see figure 3) has open holes 4 (see figure 1) around the perimeter.

Next, in the production horizontal well 2 (see Fig. 1), before the bottom 11, a string of flexible pipes 12 is lowered, for example, with a diameter of 38.1 mm. Then it is moved from the face 11 to the mouth (not shown in FIGS. 1, 2, 3), while at the same time the calculated volume of cement mortar 13 is pumped through the flexible pipe 12 (see FIG. 3).

The estimated volume of cement mortar for pouring the lower perimeter of the filter is taken equal to the volume of the filter’s inner space, divided into two, i.e. (Fk × L) / 2 = (154.5 × 10 ^-4 m ² × 400m) / 2 = 3.09 m ³ .

Cement mortar 13 in a volume of 3.09 m ³ fill the lower perimeter of the filter 5.

The well is kept for a while waiting for the cement to harden, for example 24 hours, and for sealing the holes 4 ', 4' '' (conventionally shown in Fig. 1) along the lower perimeter of the filter 5.

At the end of the exposure, the filter 5 (Fig. 3) has openings 4, 4 ”... 4 ⁿ only along the upper perimeter of the filter 5 along its entire length (L = 400 m). The production horizontal well is launched into operation.

The method of completing the construction of a producing horizontal well allows to improve the quality of the opening of a productive formation by ensuring the optimal selection of high-viscosity oil from the reservoir and aligning the profile of the influx of high-viscosity oil into the horizontal well of the producing well.

Claims (1)

A method of completing the construction of a producing horizontal well, including drilling a trunk of a producing horizontal well, launching a production string into the drilled well with a filter equipped with plugs from material that is destroyed by chemical exposure, installing a production string in the well with a filter located in the interval of the reservoir, fixing the production columns, descent into the well of the pipe string, filling the well with a chemical reagent, holding the well for a time fixing plugs in the filter openings, characterized in that in the process of drilling a producing horizontal well, the reservoir properties of the formation and their change along the horizontal well are determined, the wellbore is divided into zones that differ in filtration and capacitive characteristics of 1.5-1.6 times, depending on the filtration-capacitive characteristics, the throughput of the filter holes for each zone and the number of holes are selected, then the filter holes under the plugs are installed in the filter holes mesh filter elements, the number of which corresponds to the number of holes in each zone, are lowered into the production casing with a filter equipped with casing oil swell packers and drilled into horizontal wells with different filtering and capacitive characteristics, the production casing is fastened, then lowered into the well the pipe string and pump the chemical reagent and fill it with a filter, hold the well for the time of destruction of the plugs in ERSTU filter and washed, the reaction products then lowered coiled tubing downhole to produce its movement from the bottom to the mouth with the simultaneous injection of coiled tubing cement slurry, which is poured the lower perimeter of the filter.

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