RU2506298C1 - Producing layer filtration property modifier - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the oil industry and specifically to compositions for stabilising reservoir properties of a producing layer. The producing layer filtration property modifier contains potassium chloride or sodium chloride, scale inhibitors - dry mixture of nitrilotrimethylphosphonic acid and oxyethylidene diphosphonic acid; a water repellent which contains alkylated tertiary amines or salts thereof as the active substance, with the following ratio of components, wt %: potassium chloride or sodium chloride - 50, oxyethylidene diphosphonic acid 20, nitrilotrimethylphosphonic acid - 5, water repellent - 25. The invention is developed in subclaims.

EFFECT: modification of filtration and reservoir properties of a producing layer by reducing relative permeability for water and increasing relative permeability for oil without reducing the absolute relative permeability of the processed rock of the producing layer, which enables to change the sweep efficiency and flooding ratio of the layer and increases the oil recovery factor.

3 cl, 6 ex

Description

The invention relates to the oil industry, and in particular to compositions for modifying the reservoir properties of the reservoir.

Currently, various compositions are known that are used as modifiers of reservoir properties of the formation.

So, from the description of the patent of the Russian Federation No. 2232872 (published on July 20, 2004), a composition is known for preserving the reservoir properties of the reservoir in the near-wellbore region, which is a hydrocarbon emulsion with hydrophobic soot particles of finely dispersed carbon with a particle diameter of not more than 0.1 microns in an amount of 2 -5 wt.% And a surfactant.

Also, from the description of the patent of the Russian Federation No. 2144132 (published January 10, 2000), a composition is known that is used to preserve the reservoir properties of the bottom-hole zone of an oil well formation, which is an inverse emulsion based on a hydrocarbon and water base, the aqueous base contains a surfactant and a water-soluble salt of one or more species. As a reverse emulsion, an emulsion with a density exceeding the density of the reservoir fluid is used. It contains a water-soluble surfactant of the cationic type in an amount that ensures a decrease in interfacial tension at the contact of the aqueous salt solution with the hydrocarbon in the wellbore and the oil of the bottom-hole zone. A portion of the inverse emulsion is prepared at a ratio of hydrocarbon to aqueous base in the range (0.5: 1) to (1: 1). The density of the aqueous surfactant solution is higher than the density of the process fluid.

The disadvantages of the known compositions are technologically complex scheme for the preparation of water-hydrocarbon and reverse emulsions at low temperatures, typical for oil production in the main oil producing regions of the Russian Federation: Komi, Khanty-Mansi Autonomous Okrug-Yugra and Yamalo-Nenets Autonomous Okrug. The necessary heating of liquids in these cases leads to the destruction of the emulsion being created or to the decay of the surfactant due to exceeding the temperature limits during heating. These technologies can be used on an industrial scale only in the warm season.

The closest analogue to the patented composition is the composition stabilizer of reservoir properties of the reservoir, containing, wt.%: Nitrilotrimethylphosphonic acid 2.5-20, hydroxyethylidene diphosphonic acid 2.5-60, cationic surfactant 1.0-40, hydrophobic - hydrophobic organosilicon liquid (GKZh) 0.5-10.0, moisture absorber 5-50 (RF patent No. 2312880, published December 20, 2007).

A disadvantage of the known composition is the need to use GCR as a water repellent, the use of which leads to a sharp increase in interfacial tension at the interface: an aqueous solution of the composition, which includes GCR and oil, as well as the use of a moisture absorber.

The technical result of the patented solution is to modify the reservoir properties of the reservoir by reducing the phase permeability to water and increasing the phase permeability to oil without changing the absolute phase permeability of the treated rock of the reservoir.

The result of applying the patented solution will be a change in the coverage factors and the coefficients of water flooding, which will increase the oil recovery coefficient.

The claimed technical result is achieved by using the composition of the modifier of the filtration properties of the reservoir containing potassium chloride or sodium chloride, scale inhibitors - a dry mixture of nitrilotrimethylphosphonic and hydroxyethylidene diphosphonic acids; water-repellent agent in the form of a dry mixture containing alkylated tertiary amines or their salts as the active substance, in the following ratio of components, wt.%:

potassium chloride or sodium chloride - 50,

hydroxyethylidene diphosphonic acid - 20,

nitrilotrimethylphosphonic acid - 5,

water repellent - 25.

The ratio of hydroxyethylidene diphosphonic acid to nitrilotrimethylphosphonic acid in the scale inhibitor is preferably chosen to be 80:20.

The dry mixture of water repellent may also include ammonium salts.

Alkyl trimethylammonium chloride may be used as salts of alkylated tertiary amines.

Also, the composition of the dry mixture of water repellent, instead of ammonium salts, may contain ammonium nitrate.

The potassium chloride used in the composition is intended for the treatment of terrigenous clogged reservoirs. It is used as an effective inhibitor of clay swelling due to the replacement of sodium ions in clay by potassium ions and thus reducing the effective radius of the clay particle. In the case of processing carbonate-type formations, sodium chloride is used instead of potassium chloride as a weighting agent for the aqueous solution to better penetrate into the formation.

In this case, potassium chloride is used in the form of potassium chloride, fine, granular potassium chloride, pink potassium chloride, and sodium chloride - in the form of technical sodium chloride.

The use of dry phosphonic acids (nitrilotrimethylphosphonic NTF and hydroxyethylidene diphosphonic HEDP) in the mixture at a ratio of 20:80 will increase the efficiency of inhibition of scale deposition and their removal from the pores of the reservoir from underground pumping equipment.

A water repellent agent containing alkylated tertiary amines or their salts as an active substance leads to stable hydrophobization of the porous surface of the formation and changes the phase permeability of water and oil.

The water repellent agent, which is used as alkylated tertiary amines or their salts, in a particular case, is a liquid mixture of cationic tertiary ammonium compounds and / or salts of tertiary ammonium compounds, which are alkyltrimethylammonium chloride. To transfer the water repellent to dry form, it is proposed to apply a liquid hydrophobizator to ammonium salts, which can act either individually or together: ammonium chloride, ammonium sulfate, ammonium nitrate, followed by drying, while the Water repellent is used in an amount of 0.1- 4% of the active substance.

The listed ammonium salts act as a carrier in the preparation of a water repellent in dry form.

It should be noted that these substances do not have any hydrophobizing properties and cannot be considered as the active substance of a hydrophobizing agent. Instead of these carriers, any salt can be used: sodium chloride, potassium chloride, calcium chloride, etc.

A dry type of water repellent is prepared as follows:

In a rotary dryer with heating elements located on the outside of the drum and providing uniform heating of its contents with stepless control of the heating temperature from 50 ° C to 60 ° C, 243.5 kg of ammonium salts are charged, after which 26 kg of an aqueous solution are added mixtures of cationic tertiary ammonium compounds and / or salts of tertiary ammonium compounds, which are alkyltrimethylammonium chloride containing 6.5 kg of active substance. With the rotation turned on and heating to the indicated temperatures, the mixture is dried until a moisture content of 1.0-1.5% is reached.

The production technology of the modifier consists in mixing the components specified in the claims in a rotary type mixer for at least 1 hour. After mixing, the finished product is packaged.

To treat the well, an aqueous solution of a modifier of the filtration properties of the reservoir is prepared. The solution is prepared by dissolving the required amount of modifier in a container with water, followed by stirring until it is completely dissolved in water.

The invention is further illustrated by way of examples.

Example 1

In the Republic of Komi, when processing the terrigenous layer D ₂ st, a modifier of the following composition was used:

Potassium Chloride - 50,

Oxyethylidene diphosphonic acid - 20,

Nitrilotrimethylphosphonic acid - 5,

Water repellent - 25, which contained alkylated tertiary amines, ammonium salts.

Geological and technical data of the well:

Production casing diameter 168 mm

Perforation interval, m formation D ₂ st .: 3433.0-3434.4 m .; 3439.0-3440.0 m.; 3441.4-3442.2 m.; 3444.0-3446.8 m.; 3447.8-3449.6 m.; 3454.8-3457.8 m.; 3460.6-3462.0 m.; 3468.6-3471.6 m. The total size of the perforation interval is 15 meters

Reservoir pressure 206 atm,

The clay content of the collectors is 2.1-14.1%, an average of 6.3%. Carbonate is negligible - 0.5-3.8%.

The open porosity of the reservoirs according to core studies varies from 6 to 19.4% with a marked predominance of K _p = 14-16%, averaging 13.9%.

The gas permeability of the reservoir varies from 1.0 to 1350.3 * 10 ^-3 μm ² with a geometric mean value of 199.5 * 10 ^-3 μm ² . The vast majority of core samples studied have K _ol > 100.0 * 10 ^-3 μm ²

Before processing the well, a 6% aqueous solution of the modifier of the filtration properties of the reservoir was prepared. The solution was prepared by dissolving in a container of water with a volume of 28.2 m3 1800 kg of modifier, followed by stirring until the modifier is completely dissolved in water.

The D ₂ st formation was treated by injecting 30 m ^{3 of a} 6% aqueous modifier solution from the reservoir with the finished solution into the formation through perforation holes with a CA-320 cementing unit, at the beginning of injection, the injection pressure and pressure in the annulus were “0” atm., and at the end, the injection pressure rose to 140 atm., and the pressure in the annulus increased to 50 atm. After the injection was completed, the modifier was held in the reservoir for a reaction for 24 hours.

The results of a field test of the technology for modifying the filtration properties of the reservoir:

Fluid flow rate before stopping a well on May 25:

in the period March-May 2012 80 m ³ / day

- water cut of 87%

- oil 10.4 m ³ / day

- Liquid flow rate after treatment September 2012:

- 28.8 m ³ / day

- water cut 0.12%

- oil 28.76 m ³ days

The increase in oil production over the elapsed since the start of the well after work after the treatment with the modifier 122 days is 2240 m ³ or 1879 tons. Moreover, the effect of additionally produced oil is not associated with the intensification of its production, i.e., a simultaneous increase in liquid and oil production rates, but as a result of a change in the phase permeabilities for water and oil in the bottomhole zone and the associated redistribution of water flows in the reservoir in the drainage zone from the injection wells to production wells and, as a result, a change in the coverage coefficients of the formation and water flooding, and connection to the development of low-permeability, previously blocked oil layers.

Example 2

In the Republic of Udmurtia, when conducting field research on the use of technology combining jamming with soft treatment of the formation, an aqueous solution of the filtration properties modifier was used on the carbonate formation of the Verey horizon. The modifier used was the following composition, wt.%:

Sodium Chloride - 50,

Hydroxyethylidene diphosphonic acid - 4,

Nitrilotrimethylphosphonic acid - 1,

Water repellent - 45,

which contained alkylated tertiary amines, ammonium salts.

Geological and technical data of the well:

Production string 146 mm

At a depth of 1374 m, a horizontal lateral trunk was drilled with a horizontal section length of 150 m

Current slaughter 1375 m.

Formation pressure 123.4 atm,

The density of produced water is 1.05 g / cm ³

Before treatment of the well, 2 modifier solutions were prepared:

Solution No. 1 - 1% aqueous solution of the modifier of the filtration properties of the reservoir. The solution was prepared by dissolving in a container of water with a volume of 7 m3 70 kg of modifier, followed by stirring until the modifier is completely dissolved in water. The density of solution No. 1 was 1.18 g / cm ³ .

Solution No. 2 - 0.2% aqueous solution of the modifier of the filtration properties of the reservoir. The solution was prepared by dissolving 24 kg of modifier in a container of water with a volume of 12 m3, followed by stirring until the modifier was completely dissolved in water. The density of the solution No. 2 was 1.17 g / cm ³ .

The Verey horizon was treated by pumping 7 m ^{3 of a} 1% aqueous solution of the modifier from the tank with the finished solution No. 1 into the annulus of the well with a cementing unit CA-320; after the injection, the shutter speed for lowering the solution 31 to the bottom and penetration into the horizontal wellbore was 3.5 hours Then solution No. 2 was pumped into the annulus of the well. After the injection was completed, solutions Nos. 1 and 2 were in the well for 3 days.

The results of a field test of technology combining killing with soft treatment of the reservoir with a modifier of filtration properties:

Fluid flow rate before shutting down a well on August 20, 2012:

in the period May-August 2012 17 m ³ / day

- water cut of products of 85%

- oil 2.3 t / day

- Liquid flow rate after treatment August 26, 2012:

- 15 m ³ / day

- water cut of products 39%

- oil 4.8 tons / day.

The following are examples illustrating the use of water repellents in the modifier of example No. 1, upon receipt of which various salts were used as carriers.

Example 3

A mixture of trimethylammonium chloride and a carrier, calcium chloride, were used as a dry mixture of water repellent. This water repellent was used in the preparation of modifier prototypes when testing technology combining jamming with soft treatment of the bottom-hole formation zone at the wells of OJSC Surgutneftegas

The results of a field test of technology combining killing with soft treatment of the reservoir with a modifier of filtration properties:

The average fluid flow rate before shutdown 2006:

12 m ³ / day

- water cut of 83-90%

- oil 1.5-2.0 t / day

- Liquid flow rate after processing 2006:

- 14 m ³ / day

- water cut of products 62-64%

- oil 4.4 tons / day.

Example 4

A dry mixture of water repellent was used, consisting of trimethylammonium chloride and a carrier - a mixture of ammonium chloride and ammonium sulfate.

This water repellent was used in the preparation of modifier prototypes during testing of the technology for modifying the formation filtration properties at Rosneft-Udmurtneft.

Field tests at wells 400, 1712, 1407 of OJSC “Udmurtneft” confirmed that at a concentration of 6% aqueous solution of the Modifier, oil production in wells with water cuts of more than 95% can be increased by 2–3 times due to an increase in coverage by exposure to oil-saturated intervals, and to reduce water cut downhole production by 12-15%

Example 5

A water repellent was used, consisting of trimethylammonium chloride supported on ammonium chloride.

This water repellent was used in the preparation of modifier prototypes during testing of the technology for modifying the formation filtration properties at Rosneft-Udmurtneft.

Field tests at wells 464, 711, 947 of OAO “Udmurtneft” confirmed that at a concentration of 6% aqueous solution of the Modifier, oil production can be increased by 50-70% in wells and water cut can be reduced by 12-18% due to increased coverage by exposure to oil saturated intervals.

Example 6

A water repellent was used, consisting of trimethylammonium chloride deposited on a carrier - ammonium chloride.

This water repellent was used in the preparation of modifier prototypes during testing of acid treatment technology with modification of the formation filtration properties at OJSC Negus Neft in 2012.

Field tests at wells 854 Bush 111, OJSC Negusneft confirmed that a standard clay acid solution of 12% HCL + 3% HF + a Modifier at a concentration of 1.5% allows to increase the oil production rate in wells of Jurassic deposits by 37% and to reduce well water cut products from 45% to 19%. The total fluid flow rate did not change.

From the above examples it is seen that, depending on the technology used, the duration of the effect of using this technology varies. So for the technology of combining well killing with soft bottom-hole treatment, it was 9 days. However, it is common that the increase in oil production after treatment with working solutions containing a modifier is from 22.5 to 1205 tons / treatment. Moreover, the effect of additionally produced oil is not associated with the intensification of its production, i.e., a simultaneous increase in liquid and oil production rates, but as a result of a change in the phase permeabilities for water and oil in the bottomhole zone and the associated redistribution of water flows in the reservoir in the drainage zone from the injection wells to production wells and, as a result, a change in the coverage coefficients of the formation and water flooding, and connection to the development of low-permeability, previously blocked oil layers.

Claims (3)

1. The modifier of the filtration properties of the reservoir, characterized in that it contains potassium chloride or sodium chloride, scale inhibitors - a dry mixture of nitrilotrimethylphosphonic and hydroxyethylidene diphosphonic acids; water repellent agent containing as an active substance alkylated tertiary amines, or their salts, in the following ratio of components, wt.%:
potassium chloride or sodium chloride fifty hydroxyethylidene diphosphonic acid twenty nitrilotrimethylphosphonic acid 5 water repellent 25 2. The modifier according to claim 1, characterized in that the dry mixture of water repellent also includes ammonium salts. 3. The modifier according to claim 2, characterized in that alkyl trimethylammonium chloride is used as salts of alkylated tertiary amines.