The microemulsion composition for processing oil reservoirs

 

The invention relates to the oil industry, and in particular to compositions for the treatment of an oil reservoir to increase oil recovery. The technical result is to increase oil recovery by increasing the coverage of the reservoir flooding. The microemulsion composition for treatment of oil reservoir contains, wt%: oil-soluble surface-active substance Neprinol-GSZ 10,0-15,0, the demulsifier of 2.0 to 5.0, a hydrocarbon solvent 40,0-50,0, water the rest. The microemulsion composition has a high efficiency for enhanced oil recovery flooded reservoirs. table 2.

The invention relates to the oil industry, and in particular to compositions for the treatment of an oil reservoir to increase oil recovery.

There is a method of developing oil fields by injection into the formation through the borehole between the separating edges of the displacing agent is a composite system that includes an oil-soluble surfactant - Neprinol H3, oil and water (patent RF 2168617, IPC E 21 In 43/22, publ. 1997).

The disadvantage of this method is low efficiency due to the lack of increase in coverage of the reservoir effect.

The most is I'm a microemulsion for processing oil reservoirs, containing liquid hydrocarbon, oil-soluble surfactant, water-soluble chemical reagent and water (patent RF 2110675, IPC E 21 In 43/22, publ. 1998).

The disadvantage of this microemulsion for processing oil reservoirs is low viscosity and emulsion stability.

The present invention is to increase oil recovery by increasing the coverage of the reservoir flooding.

The problem is solved in that the microemulsion composition for treatment of an oil reservoir containing oil-soluble surfactant, a hydrocarbon solvent and water, as the oil-soluble surfactant contains emulsifier Neprinol GSZ - hydrocarbon dispersion esters of oleic, linoleic, linolenic acids, resin acids and colloidal dispersed phase, and additionally the demulsifier in the following ratio, wt.%: Oil-soluble surface-active substance Neprinol GSZ - 10,0-15,0 Demulsifier - 2,0-5,0 Hydrocarbon solvent - 40,0-50,0 Water - other Distinguishing characteristics of the designed structure are: 1. Use as an oil-soluble surfactant hydrocarbon is of oligator of Netanya GSZ.

Introduction to the microemulsion of Netanya GSZ allows, firstly, just as in the prototype, to adjust the hydrophilic-lipophilic balance of the system, and secondly, increases the viscosity and to improve the rheological properties of the microemulsion composition because of the presence of colloidal dispersed hydrocarbon phase.

This ultimately contributes to the improvement of water properties of microemulsions, improving coverage of the reservoir pressure and increase oil recovery.

2. The proposed ratio of components in microemulsion composition, wt.%: Oil-soluble surface-active substance Neprinol-GSZ - 10,0-15,0 Demulsifier - 2,0-5,0 Hydrocarbon solvent - 40,0-50,0
Water - the Rest
The specified ratio of the components contributes to the improvement of the rheological properties of the composition and increase the stability of the resulting microemulsions.

3. Introduction in the microemulsion composition addition of demulsifier, for example snpch-4410, helps to further reduce the interfacial tension at the boundary of the oil - water, oil-driving increases the properties of the composition.

When mixing Netanya-GSZ, hydrocarbon solvent, demulsifier and water produced microemu echeveste microemulsions due to the set of components, having the ability to form on the surface of the gel-like protective layers. In the process of filtration in a porous medium the microemulsion sagaseta structured, turning into a hydrophobic microemulsion, fulfilling a role on the one hand, selective water isolating material, reduces the permeability of the water - thus contributes to improving coverage impact, reduction of water production wells and, on the other hand, having a high oil-driving properties, increases the permeability of the reservoir oil due to lower its viscosity and thereby increase oil recovery.

For preparation of the inventive microemulsion composition uses the following trademarks reagents and mixtures based on them.

Oil-soluble surfactant - emulsifier Neprinol-NB represents a hydrocarbon dispersion esters of oleic, linolenic, linoleic, resin acids and colloidal phases. Produced according to TU 2458-057-17197708-01 grade (winter version) with a pour point of not higher than minus 40oS, grade B (summer version) with a pour point of not higher than minus 10oC. appearance - viscous oily dispersion from light brown to the solution of block copolymer of ethylene and propylenoxide in a mixture of methanol, water, butylcellosolve with a mass fraction of 50%. The demulsifier "snpch-4410" produced according to TU 390-57656570.OP-160-93. Appearance - clear, homogenous liquid from light yellow to yellow. The proposed composition as the demulsifier may contain any other demulsifiers: "Proglet-20/40", "Reapon-4B", "snpch-4460", "DEVON 1", "snpch-4705", "Soyuz - 2-5", etc.

As the hydrocarbon solvent microemulsion composition comprises diesel fuel, which is produced according to GOST 305-82.

Also, the proposed composition as the hydrocarbon solvent may contain any one of the following solvents:
- liquid waste hydrocarbons (GO) TU 38.303-05-27-92,
- absorbent on THE other 38.103349-85;
- VAT residue of butyl alcohols production on THE 38.1021167-85;
liquid products of pyrolysis on THE 10285-83;
- nefras different brands;
the fraction of aromatic hydrocarbons, toluene fraction in THE 38.103579.85;
- used diesel fuel in THE 6-00-0203335-41-89;
- Sporovsky the distillate is beyond 30-0147525-018-93;
the hexane fraction on THE 38.10381-83;
- wide fraction of light hydrocarbons in THE 38.101524-83.

As water microemulsion contains water m mixture components. The composition is stable at a temperature of 0oC - +40oWith in a long time. Also thermostable, withstands temperatures up to +80oC.

Example 1. The study of the stability of the microemulsion composition.

Poured into a flask with 4 ml of diesel fuel and 1 ml of Netanya-NB, then pour 4.8 ml of produced water Arlan field density 1.18 g/cm3with the addition of 0.2 l of demulsifier snpch-4410. Similarly prepare the compounds 2-6. All formulations tested for the stability of the resulting microemulsions for 35 days. The inventive microemulsion composition has a high aggregate stability of the resulting emulsions (>30 days) in comparison with the prototype (17 days) /table.1/.

Example 2. Investigation of rheological properties of the microemulsion composition. Rheological properties of emulsions are characterized by effective (e) and plastic (PL) viscosity and ultimate dynamic shear stress (0), which are measured by the instrument Rheotest-2 /PL.1/.

The results of studies of rheological properties show that the effective viscosity (e) tableindices shear stress (0increased 2.4 times. Thus, the inventive microemulsion composition on rheological parameters significantly superior to the composition of the prototype.

The efficiency of water and oil-driving properties of microemulsion composition is determined experimentally by reducing the permeability of the porous medium and growth coefficient displacement of oil by well-known methods.

Example 3. Oil-driving properties define the conditions to launder residual Nephi on an artificial model of the reservoir with a length of 40 cm and a diameter of 3 see Model under vacuum saturated with water, the weight method to determine the permeability for water (CRC - 2,88 μm2). Then under pressure in the pump model oil and exit anhydrous oil and determine the initial oil saturation, which is to 66.3%. Next upload 3 pore volumes of water. After waterflood residual saturation is 26.7%, the ratio of oil displacement by water of 0.62. Then pumped through the model one pore volume of the microemulsion of the following composition, wt.%: Neprinol GSZ 10,0, the demulsifier snpch-4410-2,0 diesel 40,0, water the rest. Push the emulsion three volumes of produced water. Residual Neptune the Oia oil 0,28. Similarly experiment with microemulsions another component of the composition. The results of experiments on the displacement of oil through the formation model are shown in table 2. Increase the displacement efficiency is 0,28-0,39 0,2 against the prototype, that is above 1.6 times.

Example 4. Water capacity of the microemulsion compositions also examine on an artificial model of the same dimensions as in example 3, in conditions close to the reservoir. Through the model, filtering the produced water with a salinity of 150 g/l at a constant volumetric flow of water 5 m3/h to stabilize the pressure drops and the cessation of oil displacement. Then pumped through the model indicates that the microemulsion composition of the following composition, wt. %: Neprinol - GSZ 10,0; the demulsifier snpch 4410; diesel fuel 40,0; water - the rest. Filtering stop, incubated for 8 h and again filtered produced water to stabilize the pressure in the reservoir model. The results of the experiments (table.2) show that the proposed microemulsion composition can significantly increase the permeability reduction of 24% in saturated and part of the reservoir, thereby to increase the coverage of the reservoir and increase nettet is considered hydrophobic emulsion, more than 30 days versus 17 prototype,
- high rheological parameters in comparison with the prototype - effective viscosity (esuperior part of the prototype by 11.7%, plastic (PL) viscosity 21.1% and the maximum dynamic shear stress (0) above in 2.4 times,
- allows to significantly increase the degree of decreasing the permeability of the reservoir water by 24% compared with the prototype in the saturated part of the reservoir, thereby to increase the coverage of the reservoir water flooding and enhanced oil recovery.


Claims

The microemulsion composition for treatment of an oil reservoir containing oil-soluble surfactant, a hydrocarbon solvent and water, characterized in that as the oil-soluble surfactant contains emulsifier Neprinol GSZ - hydrocarbon dispersion esters of oleic, linoleic, linolenic acids, resin acids and colloidal dispersed phase, and additionally the demulsifier in the following ratio, wt. %:
Oil-soluble surface-active substance Neprinol GSZ - 10,0-15,0
Deamong the

 

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