RU2230897C2 - Method for hydrophobic treatment of pit-face area of productive bed - Google Patents

Abstract

FIELD: oil and gas extractive industry.

SUBSTANCE: method includes treatment of rock in pit-face area of productive bed by hydrophobic compound - solution of polymethylhydrohexane in organic fluid, which is pumped through rock of pit-face area of bed, passive time lag, transfer into mode of hydrocarbon influx, as said solution a 0.06-0.36% solution of polymethylhydrosiloxane in condensate, which is pumped at volume, equal to 1-3 volumes of porous space of rock of treated area, and passive time lag duration is 1-1.5 days.

EFFECT: higher reliability, sandstones have water-repellent properties, without lessening of effective cross-section of transporting channels.

5 ex, 2 tbl, 1 dwg

Description

The invention relates to the oil and gas industry, in particular to methods for increasing well productivity due to physico-chemical effects on the reservoir.

During the opening of sandstone formations, changes in their filtration parameters occur, which affect the productivity of the wells and their production characteristics. In order to restore the productivity of wells, a large number of methods of stimulating the formation are used: thermal, gas, hydrodynamic, microbiological, physicochemical, and also their various combinations [M. Abasov and other Modern methods of increasing oil recovery. ISTC "Oil recovery". - M .: Nauka, 1992, p. 5-130]. However, most of them are not sufficiently effective, difficult to implement, energy intensive and require the use of expensive reagents.

A known method of processing the bottomhole formation zone [A.S. USSR No. 1327594, Е 21 В 43/27, 1985], which provides for the injection into the specified zone of a mixture of oil and water-soluble surfactants in a hydrocarbon liquid. The disadvantage of this method is its low efficiency, which consists in the fact that mixing substances with opposite surface activity (hydrophilization and hydrophobization) leads to their mutual deactivation.

Also known is a method of increasing oil recovery, including treating the bottom of the formation with a suspension of a hydrophobic reagent in an organic solvent [RF Patent No. 2015142, E 21 B 43/22, 1996]. The disadvantage of this method is that the hydrophobic agent (silicon oxide) is absolutely insoluble in the organic solvent carrying it and, despite a rather high degree of dispersion, is able to precipitate under the influence of gravitational forces, narrow the diameters of sandstone transport channels and deteriorate them as a result filtration properties.

The closest is the method of hydrophobic treatment of the bottom-hole zone of the reservoir, including the treatment of the rocks of the bottom-hole zone of the reservoir with a hydrophobic composition - dispersion or a solution of organopolysiloxane, including polymethylhydrosiloxane, in concentrations of 0.0664, 0.0629, 0.0397%, in an organic liquid - kerosene, diesel fuel, various products of oil distillation, crude oil, which are pumped through the rocks of the bottom-hole zone of the formation, keeping the well at rest 0.5 or 7 days, then transfer to the mode of hydrocarbon inflow (US Patent No. 4197912, E 21 B 43/22, 04/15/1980).

The technical result is to increase reliability, giving the sandstones water-repellent properties, without reducing the effective cross-section of the transport channels.

The technical result is achieved by the fact that in the method of hydrophobic treatment of the bottom-hole zone of the reservoir, including the treatment of the rocks of the bottom-hole zone of the reservoir with a hydrophobic composition - a solution of polymethylhydrosiloxane in an organic fluid that is pumped through the rocks of the bottom-hole zone of the formation, shuttering the well at rest, and transferring it to the flow of hydrocarbon, as the specified solution use a 0.06-0.36% solution of polymethylhydrosiloxane in the condensate, which is pumped in a volume equal to 1-3 volume Am pore space of rocks treatment area, and wells extract alone carried 1-1.5 days.

The following examples illustrate the feasibility, technical utility and effectiveness of the invention.

Example 1

Condensate solubility of polymethylhydroxyloxane

The tests showed (Table 1) that polymethylhydroxyloxane (PMHS) is mixed with condensate in any proportions, forming a homogeneous transparent solution. In addition, it is well soluble in individual aliphatic (from C ₆ to C ₁₀ ) and aromatic (benzene, toluene, xylene) hydrocarbons.

Example 2

Determination of wetting angles (table. 2)

Polished quartz glass plates are treated with boiling 5% hydrochloric acid. Washed with distilled water until a negative reaction to the chlorine anion. Dried at 105 ° C. One of the plates (1) is left with a hydrophilic surface, and the rest are moistened with condensate (2) and condensate solutions of PMHS (3-7). Dry the plates in air in an upright position. Further, according to the standard method, the contact angle of the surface with distilled water is determined. On each plate fits 5-7 drops. The measurement results confirm the hydrophobic effect of the composition used.

Example 3

5 ml of a 0.214% condensate solution of PMHS are brought into contact with 15 g of glass microspheres with a diameter of 0.6-1 mm and a specific surface area of 0.1 m ² / g. Mix thoroughly and leave it alone for 24 hours, after which the solution is separated from the microspheres and determined by NMR on the H nuclei the content of PMHS. The average result from three parallel experiments is 0.170%. The adsorption value of PMGS is equal to 0.015 g / m ² .

Example 4

Two samples of sandstone parfenovskogo prepared for filtration studies according to standard procedures, is contacted with a 0.1% solution of PMHS in the condensate so that the cores were immersed in hydrophobicizing composition ~ _^1/4 height. The container is sealed, left alone for 1 day. Then the samples are dried in air, saturated with formation water, and water permeability is determined. The drawing shows the results of the study, which confirm the positive effect of the hydrophobizing composition on the filtration properties of sandstones. It can be seen that q / AP increases on average 1.5-1.6 times.

An increase in the permeability of the bottom-hole formation rocks is accompanied by an increase in well productivity. Thus, a significant difference between the invention and the prototype method is its great reliability, since a hydrophobizing agent solution is used to give the sandstones water-repellent properties, rather than a suspension, from which the hydrophobizing agent can be trapped in a porous medium, which may reduce the effective cross section of the sandstone transport channels and as a consequence, a decrease in their permeability.

 Example 5

Hydrophobic treatment of bottomhole rocks of clayed terrigenous strata with a condensed solution of polymethylhydrosiloxane.

The essence of the proposed treatment method consists in pumping a condensate 0.36% solution of an oil-soluble hydrophobizing agent, polymethylhydrosiloxane (PMHS), into the bottomhole zone of the reservoir, followed by exposure of the solution to the reservoir for 24 hours. This time is enough to complete the adsorption of PMHS on the surface of the filtration pores and sandstone channels.

The list of equipment necessary for the implementation of hydrophobic treatment of the bottomhole formation zone:

- cementing aggregates (CA-300; CA-320; CA-400);

- pumps (2AN-500; 4AN-703);

- tubing (63.5; 73.0; 102 mm);

- packer (PS 5 ’’ - 500; PS 6 ’’ - 500; PG5 ’’ - 500);

- wellhead fittings (AU-5; AU-6).

Preparation of hydrophobic composition

As a solvent, dehydrated (dry) condensate of the Kovykta field is used. A water-repellent agent is an organosilicon fluid of 136-157 M grade, produced by Siberian Silicone JSC in accordance with TU 6-02-694-76 with a change of 1-3. To prepare a condensate solution of PMHS, an appropriate volume of a polyethylene or metal container with a gummed or enamel coating, equipped with a mixing device, is required.

Preparation of hydrophobic composition. Condensate is poured into the tank, and PMGS is added thereto at the rate of 2.6 kg of PMGS per 1 m ³ (0.721 t) of condensate. The solution is thoroughly mixed and used as intended.

The volume of hydrophobic composition

The volume of the solution for hydrophobic treatment of the rocks of the bottom-hole formation zone is calculated based on the planned treatment radius using the formula:

V = π (R ² -r ² ) mh, m ³

where V is the required volume of water-repellent composition, m ³ ;

R is the radius of the treated zone of the reservoir, m;

r is the radius of the well, m;

m is the coefficient of porosity of the rock;

h is the power of the processed interval, m

Technology for injecting water-repellent composition

The technology of hydrophobic treatment of the rocks of the bottomhole zone of the clayed terrigenous strata with the PMGS condensate solution consists of a series of sequential operations:

- preparation of the required amount of 0.36% solution of PMHS in the condensate;

- placement of a water-repellent composition (0.36% condensate solution PMGS) in the tubing and in the well;

- injection into the reservoir under pressure of the entire volume of the prepared hydrophobizing composition with the subsequent supply of squeezing liquid (pure condensate) in an amount equal to the full volume of the tubing;

- impregnation of the formation with a hydrophobic composition in static conditions with a blocked pipe and annular space for 24 hours;

- at the end of the processing period, they begin to discharge the well and cause the inflow. During well cleaning, sampling of the spent solution is carried out to determine the amount of water repellent in it.

Claims (1)

The method of hydrophobic treatment of the bottom-hole zone of the reservoir, comprising treating the rocks of the bottom-hole zone of the reservoir with a hydrophobic composition - a solution of polymethylhydrosiloxane in an organic liquid, which is pumped through the rocks of the bottom-hole zone of the reservoir, shuttering the well at rest, transferring to the hydrocarbon flow regime, characterized in that as specified the solution use a 0.06-0.36% solution of polymethylhydrosiloxane in the condensate, which is pumped in a volume equal to 1-3 volumes of the pore space the rocks of the treated zone, and the well is kept at rest for 1–1.5 days.