SU1717801A1 - Method of bottomhole zone treatment in oil and gas reservoirs - Google Patents

Abstract

FIELD OF THE INVENTION The invention relates to the oil and gas industry, in particular, to methods of production intensification. The goal is to increase the efficiency of the bottomhole treatment of a flooded formation by reducing the permeability of retracted cracks. A fracturing fluid, a mixture of sand and granulated magnesium in a carrier fluid is pumped into the well, simultaneously or directly behind the mixture, a granulated asphaltene-resinous softener or a bituminous structurant. maintain them in the reservoir, then remove the fracturing fluid and the carrier fluid. The method makes it possible to reduce the inflow of water to the wells through cracks during insulation works by 56 times, and when carrying out complex technology for isolating water inflow through cracks and hydroacid treatment of low-permeable blocks of rock, 76 times. 2 ill., 1 tab.

Description

The invention relates to the oil and gas industry, in particular to methods for intensifying oil and gas production and limiting the flow of produced water.

A known method for isolating formation water by pumping a reagent into watered cracks reacts with the formation water to form a precipitate, granular magnesium being used as a reagent.

The disadvantages of this method are the high consumption of magnesium, which is filled with cracks, and the insufficient degree of filling with magnesium of cracks, which are the ways of water inflow.9.

There is a known method for isolating the inflow of formation water into wells, including the injection of fracturing fluid, a mixture of sand with granulated magnesium into formation cracks and the creation of conditions for the magnesium hydrolysis reaction to occur.

The method also does not allow to sufficiently isolate the flow of water into the well.

Closest to the present invention is a method for treating the near-wellbore zone of an oil reservoir, which involves injecting a fracturing fluid, magnesium in a carrier fluid, removing a fracture fluid and a carrier fluid, and after 48-60 hours injection of acid into the reservoir. .

The disadvantage of this method is low processing efficiency.

The aim of the invention is to increase the efficiency of treatment of the near-well zone of the watered formation by reducing the permeability of watered cracks.

This goal is achieved by the fact that simultaneously with the injection of a mixture of sand and granule V |

00

about

granulated magnesium in the carrier fluid or directly behind it, a granulated asphaltene-resinous emollient or a bitumen structurant is injected into the formation.

The composition of the mill ASMG is the following,%: asphaltenes 38.7-40.4, - resin 24.6-24.3; oil 31.7-35.3; sulfur 0.6-0.8%; paraffin 0.4-0.6; ash 0,2-0,3; carbon black 1,5-6,0.

The physicochemical properties of the mAchE solvent are as follows:

substance density within 990-1040 kg / m3; bulk density (apparent s) density 400 kg / m3; softening temperature 65-90 ° С; melting temperature in the range of 125-135 ° С. In water, 99.9% by weight of the microchute floats up (due to the lower density and hydrophobicity of the surface).

The diameter of the particles according to the sieve method is in the range of 0.125-2 mm. The modal particle diameter (0.25 mm, weighted average by fraction is 0.457 mm. The content of particles larger than 5 mm is absent, particles smaller than 0.2 mm make up no more than 10%. The emollient is well soluble in aromatic hydrocarbons (toluene, benzene), partly in polar (dichloroethane, chloroform) and nonpolar (diethyl ether) solvents. In light petroleum products (gasoline, kerosene, gas condensate, diesel fuel), the softener partially dissolves (taken 0.5 gm softener). per 10 ml of solvent, observed for 24 hours.) As the amount of solution increases The solvent in the mixture swells off the melt, and then dissolves to form a fluid fluid viscous mass. The humidifier is chemically and physically inert with respect to water and aqueous solutions of substances used for enhanced oil recovery: solutions of 10% surfactant concentration, 1% PAA concentration, 3% hydroxide concentration (caustic soda) and sodium silicate (liquid glass) sodium; 98% concentrated sulfuric acid and carbon dioxide (gas, carbonized water). The softener does not dissolve in water-based micelle solutions (Carpatone-2). In micellar solutions with an external hydrocarbon phase (oil-based microemulsion), its partial dissolution takes place. ASMG is used in the rubber and tire industries. The softening temperature is at least 145 ° C, and the flashes in the open crucible are not lower than 240 ° C. In benzene, chloroform or trichloroethane it dissolves at least 99.5%, swells and dissolves in large quantities of oil, is inert to

water (contains not more than 0.3% of water-soluble compounds).

The composition of bitumen structure-bodies.

Group composition, wt.%: Paraffin-naphthenic 13.7-15.0; monocyclic aromatic 10.0-11.6; bicyclic aromatic 2.7-4.9; Resins 25.7-34.8: Asphaltenes 17.2-26.3.

Elementary composition, wt.%: Carbon 85,46-85,65; hydrogen 10.06-10.75; sulfur 2.81- 2.89; nitrogen and oxygen 0.95-1.4.

For conducting laboratory studies, a model of a fracture was modeled. The crack is made in a rubber cylinder with a diameter of 28 mm and a height of 24 mm and reinforced with a brass frame. The maximum crack width is 2.4 mm, length is 42 mm, height is 24 mm. Laboratory experiments were carried out on a standard installation UMPK-IM. The crack model was completely filled with a mixture of sand and magnesium in the ratio of 80% sand and 20% magnesium (MD) and placed in the core holder. A hydrochem pressure of 4.0 MPa was created, the model of cracks was saturated with technical water, and water permeability was determined. It was 65.6 µm2, after which the crack model was left for 3 days to react. Due to the fact that granular magnesium (MD) interacts with water and its hydrolysis occurs, the permeability after 3 days of water was 40.5 μm, i.e. decreased 1.6 times. However, the full reposition of the crack does not occur due to the fact that when a sand-magnesium mixture is injected into a vertical crack, it is deposited at the bottom of the crack, accumulated to a certain level and transferred into the depth of the crack. The upper part of the crack remains free of plugging mixture. The pumping pressure at the beginning of the process was 0.01 MPa, after 3 days, 0.03 MPa.

When an injected mikytel accumulates it occurs in the upper part, and the bottom is free. When jointly and especially consistently pumping the sand-magnesium mixture into a vertical crack, it is deposited at the bottom of the crack, accumulated to a certain level and transferred to the depth of the crack. The upper part of the crack remains free of plugging mixture.

The height of the alluvium layer is 70-79% of the total crack height and is described by the dependency shown in FIG. 1, on which you use the symbols:

h. .. U oh.

P

t} 0

Hi -

U off

where h is the layer thickness;

t о - crack height;

Uo mix speed; oh oh

g is the mixture flow rate; d - crack opening; Uo is the sedimentation rate;

p is the concentration equal to

..H .. g

flr consumption of granules (particles) of the mixture.

From the analysis of FIG. 1, it follows that 30–21% of the height (volume) of the crack remains unfilled with a sand-magnesium mixture, which means there is residual conductivity of the entire crack with a layer of sand-magnesium mixture.

FIG. 2 shows a diagram of an apparatus for carrying out the method.

Conducted laboratory studies established the optimum ratio of the sand-magnesium mixture and softener (structurant), at which the minimum permeability of the plugging layer is reached. In the Crack Model, a sand-magnesium mixture was filled (the optimum ratio of magnesium and sand in the sand-magnesium mixture is 80% sand and 20% magnesium). A hydrochem pressure of 4.0 MPa was created, the fracture model was saturated with technical water, and water permeability was determined. Thereafter, the fracture model was allowed to react for 48-60 hours, after which the water permeability was again determined. Then, 40 ml of 15% hydrochloric acid was pumped through the fracture model and left to react for a day. After one day, water permeability was determined. The results of the experiments are summarized in the table.

From the results of the table it follows that the optimum ratio of plugging, mixture is 21-30% softener (or structurant) and 70-79% of sand and magnesium mixture. When the ratio of 70% of the sand-magnesium mixture and 30% of the solvent or builder under the conditions of the prototype was 40.5 µm2. The permeability of the sand-magnesium mixture together with the softener was 0.53 μm 2, i.e. decreased by 76 times.

Thus, with the same ratios of magnesium and sand in the mixture, the proposed method makes it possible to fill the entire cross-section of watered cracks with plugging material and completely block the paths of undesirable acid flow into the formation and premature water flow into the well.

The use of the proposed method for isolating the inflow of formation water into the well ensures complete isolation of the inflow of water along the fractures, the absence of erosion and

5 dissolving magnesium hydroxide from the sand layer, increasing the duration of the effect and improving oil production from low-permeability formation elements.

The method is carried out as follows.

Pre-sanding unit 7 load sand-magnesium mixture. Subsequently, the sandy-magnesium dough is fed by means of a sand mixer 15. Two cement mixing units 4 supply water from the tank 8 to the hydraulic mixing device, into which the softener is poured. The concentration of the softener slurry is controlled by the feed.

20 m of gchitel to the mixing hopper. From the trough 5, the grinder slurry is taken out by two cementing aggregates and fed to a sandmixing aggregate 7, from where the sand-magnesium mixture

25 and the softener are taken by pumping units 4 and, through a block of manifolds, are pressed into the well. After injection of the sand-magnesium mixture and softener, it is necessary to carry out the acid treatment.

30 Therefore, it is necessary to include an acid tank, shown by the dotted line in FIG. 2

Example 1. An injection well flooded a reservoir element.

35 500x250x20 m. The reservoirs are fractured-porous deposits with a fracture coefficient of 0.0002. Based on the fact that 10% of the cracks will be treated, the amount of the necessary sand and magnesium mixture together with the softener is determined: (500x250x20) 0.1-0,0002 - 50 m3. On the basis of laboratory studies, it is necessary to take 20 m of sand, 7 m of magnesium and 15

45 m m gchitel. The concentration of pulp injection of 20 kg / m3. Using a sand-mixing unit 4 PA and two pump units 4 AN-700, 50 m of a sand-magnesium mixture is pumped along with a softener. After rolling the slurry pulp and pushing it into the reservoir, the well is put into operation. The impact on the reservoir element through the oil and gas wells is carried out similarly. Example 2. An injection well watering a reservoir element 500x250x20 m. The reservoirs are fractured-porous deposits with a fracture factor of 0.0002. Based on the fact that, 10% of the cracks are subject to processing, the amount of the necessary sand-magnesium mixture is determined together with the softener:

(500x250x20) 0.10,0002 - 50 m3.

Based on the laboratory tests, it is necessary to take 28 m3 of sand, 7 m of magnesium and 15 m of mcchitel for the work. Pulp injection concentration of 20 kg / m. With the help of a sand-mixing unit 4 PA and two pumping units 4 AN-700, 35 m3 of sand-magnesium mixture is pumped in, followed by 15 m of smoker. After the reagent has been pumped into the reservoir, the well is put into operation. The impact on the reservoir element through the oil, gas well is similar.

As a result of the implementation of the method of examples 1 and 2, the permeability and flow rates of fluids in the well will change.

The ratio of sand and magnesium is

728

28-T7: WT7 OR 20 AND 8C

The ratio of sandy-magnesium mixture and softener is

28 + 7 + Jl5: 28 + 17 + 5 or 70 and 30% Laboratory experiments for the specified ratios of materials have established that the tampon permeability is: for the sand-magnesium mixture (prototype), the initial permeability is 65.6 μm, after hydrolysis 40.5 μm, t. e. decreased 1.6 times; for a sandy-magnesium mixture of a softener (reduction of permeability of watered cracks before the operation of a well), the initial permeability is 1.14 μm2 (57 times less than in the prototype); for a sand-magnesium mixture and a softener with subsequent pumping of hydrochloric acid (stage before acid treatment), the final permeability after hydrolysis and pumping of hydrochloric acid is 0.53 μm2 (76 times less than in the prototype).

Thus, increasing the efficiency of treating the near-abdominal zone of the flooded formation by reducing the permeability of the flooded cracks is 56 times the implementation of the water inflow isolation technology and 76 times the implementation of the integrated exposure technology.

PRI me R 3. An injection well flooded a reservoir element of 500x250x20 m. The reservoir is fractured-porous with a fracture factor ™ 0.0002.

Based on the fact that 10% of the cracks will be treated, the amount of the necessary sand-magnesium mixture is determined along with the softener.

(600 x 250 x 20) 0.1-0,0002 60 m3.

To carry out the work, it is necessary to take 33.6 M3 of sand, 8.4 m3 of magnesium and 18 m3 of a structurant. The sand / magnesium ratio is 20: 80%. The ratio of sand and magnesium mixture and softener

70: 30%.

Wells before the treatment, worked with a water flow rate of 42 mg / day with a water cut of 78%. After treatment, the inflow of water decreased 56 times, i.e. amounted to 0.75 m3 / day,

Claims (1)

Invention Formula The method of processing the bottomhole zone of oil and gas reservoirs, including injection of fracturing fluid, a mixture of sand and granulated magnesium in a carrier fluid, extraction of fracture fluid and a carrier fluid, and after 48-60 hours injection of acid into the reservoir, which differs from in order to increase the processing efficiency of the bottom-hole watered zone the reservoir by reducing the permeability of watered cracks, simultaneously with the injection of a mixture of sand and granulated magnesium into the carrier fluid or directly behind it, granulated asphaltene-resinous softener, or bitumen structurant with a volume ratio in the formation of the amount of the mixture of sand and granulated magnesium to the amount of granulated asphaltoresistant softener or bitumen structurant (70-79) :( 30-21). four Fig 2