RU2291959C1 - Method for processing face zone of oil pool - Google Patents

Abstract

FIELD: oil extractive industry, in particular, methods for processing face zone of oil pool, possible use for increasing efficiency of oil extraction.

SUBSTANCE: method for processing face zone of oil pool includes successive forcing in of blocking reagent and acidic composition. As blocking reagent, oil is used taken from oil preparation plants, with viscosity of 1,0-100,0 mPa*s and water content less than 5,0% or hydrocarbon composition - marginally soluble surfactant in hydrocarbon - with mineralized water with density of 1050-1120 kg/m³ with ratio 1:2 respectively, or water solution of polyacrylamide with concentration 0,1-0,3%, as acidic composition, compound composed of, in percents of mass: hydrochloric acid or mixture of hydrochloric and hydrofluoric acid 25,0-80,0, water-methanol fraction - side product of production of technical phosphorous acid or methanol (of methanol) 1,0-24,5, technical lignosulphate 2,0-20,0, nonionic surfactant 0,1-5,0, water the rest, blocking reagent and acidic composition are used in volumetric ratio equal to 1:0,5-3,0 respectively.

EFFECT: increased efficiency of method for processing face zone of oil pool, blocking of highly penetrable water-saturated seams, thus making it possible for acidic composition forced in later to penetrate deeper into water-oil saturated and oil saturated pools.

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Description

The invention relates to the oil industry, in particular to methods for processing the bottom-hole zone of an oil reservoir, and can be used to increase the efficiency of oil production.

Treatment of the bottom-hole zone of the formation with blocking compounds leads to the temporary shutdown of highly permeable flooded layers of the oil reservoir with chemicals, followed by an increase in the permeability of oil-saturated layers not covered by flooding.

A known method of acid treatment of the bottom-hole zone of an oil reservoir, including: sequential injection of a hydrophobic emulsion with chalk powder, hydrophobic emulsion and hydrochloric acid (ed. St. USSR No. 1104244, class E 21 B 43/27, 1984).

However, the method is not sufficiently effective and technologically advanced, since the compositions used are expensive, and their preparation is laborious.

A known method of processing the bottom-hole zone of a heterogeneous permeability of a water-saturated formation, including the sequential injection of a sediment-forming agent, organosilicate of sodium hydrochloric acid and mud acid (ed. St. USSR No. 1104245, class E 21 B 43/27, 1984).

However, the known method is not technologically advanced, time-consuming and time-consuming and can only be used for injection wells.

The closest in technological essence and the achieved effect is known method of treating the bottom-hole zone of a heterogeneous oil reservoir, including sequential injection of a sediment forming reagent selected from the group: technical lignosulfonate or technological liquid containing an aqueous solution of calcium salts and sulfite liquor or a composition containing an aqueous solution of technical and lignosulfonate organic additives and an acid reagent selected from the group: hydrochloric acid, or a mixture of hydrochloric and hydrofluoric acid from or a composition containing a solvent, a surfactant and hydrochloric acid, or a composition containing an aqueous solution of hydrochloric and hydrofluoric acids, a surfactant, inorganic salts and a solvent, the precipitating and acid reagents being taken in a ratio of 1: 1, respectively (RF patent No. 2065951, class E 21 43/27, 1996).

However, the known method is not sufficiently technological and efficient.

The present invention is based on the development of a technological and effective method for treating the bottom-hole zone of an oil reservoir, which allows blocking of highly permeable water-saturated layers, which allows the acid composition injected in the subsequent penetration deeper into the water-saturated and oil-saturated formations.

The problem is solved in that in the method for processing the bottom-hole zone of an oil reservoir, which includes the sequential injection of a blocking reagent and an acid composition comprising a surfactant surfactant, water and hydrochloric acid or a mixture of hydrochloric and hydrofluoric acids, oil from treatment plants is used as a blocking reagent oil with a viscosity of 1.0-100.0 MPa · s and a water content of less than 5.0% or a hydrocarbon composition — an oil-soluble surfactant in a hydrocarbon — with mineralized water with a density of 1050-1120 kg / m ³ , respectively The ratio is 1: 2, respectively, or an aqueous solution of polyacrylamide at a concentration of 0.1-0.3%, the acid composition contains a surfactant nonionic and additionally water-methanol fraction - a by-product of the production of industrial phosphorous acid or methanol and technical lignosulfonate in the following ratio of components, wt.% :

hydrochloric acid or a mixture of hydrochloric and hydrofluoric acids 25.0-80.0 water-methanol fraction - side phosphorous product technical acid or methanol (methanol) 1.0-24.5 technical lignosulfonate 2.0-20.0 nonionic surfactant 0.1-5.0 water rest,

a blocking reagent and an acid composition are used in a volume ratio of 1: 0.5-3.0, respectively.

Oil for injection as a blocking reagent is taken from oil treatment plants in accordance with GOST 9965-76 with a viscosity of 1.0-100.0 MPa · s and a water content of less than 5.0 wt.%.

The hydrocarbon composition is taken according to TU 2458-OP-004-27823669-01. It is an oil-soluble surfactant, e.g., AF ₉ -4 (TU 2483-077-05766801-91) in a hydrocarbon, for example diesel fuels (CRP 305-82), which is injected with saline water (a density of 1050-1120 kg / m ³⁾ in a ratio of 1: 2.

As an aqueous polymer solution, for example, an aqueous solution of Alcoflood-935 or Accotroll-622 polyacrylamide is taken at a concentration of 0.1-0.3 wt.%.

The acid composition is prepared under industrial production conditions or at the wellhead by sequentially dosing and mixing the components.

To prepare the acid composition take: hydrochloric acid according to TU 38-103141-78; a mixture of hydrochloric and hydrofluoric acids according to TU 6-01-14-78-91; water-methanol fraction - a by-product during the hydrolysis of the bottom residue of dimethyl phosphate in the production of technical phosphorous acid according to STP-145-95; technical methanol according to GOST-2222-78; technical lignosulfonate according to TU 13-028-1036-029-94, nonionic surfactants neonols AF9-6, AF9-12 according to TU 38.507-63-300-93. Options for the prepared compositions are shown in table 1.

According to the claimed method, oil or a hydrocarbon composition with mineralized water or 0.1-0.3% aqueous polymer solution is injected, which fill highly permeable water-saturated layers and contribute to their temporary blocking. Next, the acid composition is pumped in a volume of 8.0-18.0 m ³ , which penetrates far into the formation into zones that are not covered or are poorly covered by exposure. The acid composition is pressed into the reservoir with oil in a volume of 5.0-6.0 m ³ .

Table 2 shows specific examples of the method.

The increase in oil production is achieved by improving the permeability of the bottomhole zone of the well and washing out the asphalt-resin-paraffin deposits of paraffin deposits; isolation of water saturated zones. The application of this method allows to increase the oil production rate by 0.8-5.8 tons / day. compared with the prototype while maintaining the water content of the product.

Claims (1)

A method for treating the bottom-hole zone of an oil reservoir, comprising sequentially injecting a blocking reagent and an acid composition comprising a surfactant surfactant, water and hydrochloric acid, or a mixture of hydrochloric and hydrofluoric acids, characterized in that oil is used as a blocking reagent from oil treatment plants with viscosity 1.0-100.0 MPa · s and water content less than 5.0% or a hydrocarbon composition - oil-soluble surfactant in a hydrocarbon - with mineralized water with a density of 1050-1120 kg / m ³ in a ratio of 1: 2, respectively , or an aqueous solution of polyacrylamide at a concentration of 0.1-0.3%, the acid composition contains a surfactant nonionic and optionally water-methanol fraction - a by-product of the production of industrial phosphorous acid or methanol and technical lignosulfonate in the following ratio, wt.%: Hydrochloric acid or hydrochloric acid mixture and hydrofluoric acids 25.0-80.0 Water-methanol fraction - side phosphorous product technical acid or methanol (methanol) 1.0-24.5 Technical lignosulfonate 2.0-20.0 Nonionic surfactant 0.1-5.0 Water Rest a blocking reagent and an acid composition are used in a volume ratio of 1: 0.5-3.0, respectively.