RU2460753C1 - Fluid for well killing - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: fluid for well killing contains, wt %: gas condensate 10.0-15.0, glycerine 15.0-20.0, potassium muriate 3.6-5.0, sulphacell 2.0-5.0, ferrochromelignosulphonate 1.0-2.0, disolvan 0.5-2.5, water 59.0-61.5.

EFFECT: maintaining initial formation permeability.

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Description

The invention relates to the field of oil and gas production, in particular to compositions for killing wells, and can be used at enterprises of the oil and gas industry for overhaul of wells.

Known liquid for killing wells (RF patent No. 2115686, ЕВВ 43/12, 07/20/1998), containing, wt.%: Calcium chloride 1-40, organic solvent, incl. glycerin, 10-50, an inhibitory salt, including potassium chloride, 1-10, water the rest.

The disadvantage of this killing fluid is that it does not preserve the initial permeability of the formation and has significant zones of penetration in the bottomhole zone of the formation after killing the well.

The closest analogue is a liquid for killing wells, including, wt.%: Gas condensate 81.0-84.9, synthetic fatty acid (FFA) 1.7-2.3, caustic soda (NaOH) 0.6-1, 0, clay rest.

The disadvantage of this killing fluid is that when the clay component — clay powder — penetrates into the pore space, an additional colmatation of the reservoir pores occurs, which will cause a sharp decrease in the permeability of the bottom-hole formation zone. An additional decrease in the permeability of the formation is caused by the reaction of caustic soda NaOH with the clay component of rock cement, which leads to the formation of insoluble sediments in the pore space of the reservoir.

The objective of the invention is the development of fluid killing oil, gas and gas condensate wells, reducing the time of development and withdrawal of wells after repair to the pre-repair mode of operation of the well.

Achievable technical result consists in creating a fluid for killing wells that preserves the initial permeability of the formation.

The essence of the invention lies in the fact that the liquid for killing wells contains gas condensate, glycerin, potassium chloride, sulfacell, ferrochrome lignosulfonate (FHLS), disolvan, water in the following ratio, wt.%:

Gas condensate 10.0-15.0 Glycerol 15.0-20.0 Potassium chloride 3.6-5.0 Sulfacell 2.0-5.0 Ferrochromlignosulfonate 1.0-2.0 Disolvan 0.5-2.5 Water 59.0-61.5

From the analysis of scientific, technical and patent literature, the use of the claimed combination of glycerol and potassium chloride, gas condensate, water with the addition of sulfacell, ferrochrome lignosulfonate, is dis solved in the composition of the fluid for killing wells in their proposed quantitative ratio.

In the present invention, the claimed composition of the ingredients of the kill fluid in this ratio allows you to get a solution with optimal technological parameters. The mutual influence of the components on each other contributes to the hydrophobization of the reservoir surface, which eliminates the penetration of the aqueous phase of the kill fluid into the formation and preserves the initial permeability of the formation.

Stable gas condensate (TU 51-05751745-09-97) is produced by the Novy Urengoy gas processing plant.

Glycerol (triethylene glycol) trihydric alcohol is a colorless thick syrupy liquid with a sweet taste heavier than water (p = 1260 kg / m ³ at a temperature of 15 ° C). It has a low surface tension. Easily soluble in water and alcohol, mixing with them in any ratio (GOST 6824-96). It has no toxic and irritating effect. Environmentally friendly. The molecular formula of glycerol is CH ₂ ONSONCH ₂ OH.

Manufacturers

1. Sterlitamak PA Caustic

2. Kemerovo Production Association Khimprom

3. Sumgait software "Orgsintez"

4. Perm Chemical Plant

Potassium chloride (KC1) (GOST 4568-83) is a white crystalline powder, hygroscopic, completely dissociates in an aqueous solution, and is an inhibitor of clay hydration and dispersion.

Sulfacell - water-soluble hydroxyethyl cellulose (HEC) (TU 6-55-221-1407-95) - a product of white or yellowish-white color, it is easily soluble in water, is used to thicken the solution, to create a structure that can hold the composition in suspension ( system stability for 10 days), and reduced filtration. CJSC “Polycel” is produced in Vladimir.

Ferrochromlignosulfonate (FHLS) (TU 2458-014-7001-156-98) - a powder that is highly soluble in water, designed to reduce the viscosity of the filtration of fresh and medium-saline waters. The optimal additive is 0.5-2.0% in the form of a powder or in the form of a solution of 10-40% concentration.

Disolvan 4490 is a surfactant, used to remove chemicals from the bottomhole formation zone.

For experimental verification of the kill fluid, three formulations were prepared (Table 1). The technology for preparing the solution is as follows.

The calculated amount of glycerol is introduced into fresh water and mixed on a Voronezh laboratory stirrer at 300 rpm for 10 minutes. Then, gas condensate is introduced into the water-glycerin mixture to reduce the density of the solution and the estimated amount of sulfacell filtration reducer with continuous stirring until completely dissolved. With further stirring, the calculated amount of potassium chloride, ferrochromlignosulfonate and disolvane is introduced into the solution. After obtaining a homogeneous system, the solution is mixed for another 30 minutes.

Measurement of the main technological parameters of the obtained killing fluid is carried out on standard instruments.

The best parameters for composition No. 3 (table). The data in the table show that the proposed fluid for killing wells in comparison with the fluid of the prototype fully preserves the initial permeability of the formation after killing (coefficient of recovery of permeability of the formation after killing). Permeability recovery coefficient of 100%. The indicated properties of the proposed fluid for killing wells allow it to be used for Cenomanian gas deposits in Western Siberia, where the reservoir pressure after long-term operation is significantly lower than hydrostatic (anomalously low reservoir pressure ANPD).

Claims (1)

The liquid for killing wells, including gas condensate and water, characterized in that it further contains glycerin, potassium chloride, sulfacell, ferrochrome lignosulfonate, disolvan in the following ratio, wt.%:
Gas condensate 10.0-15.0 Glycerol 15.0-20.0 Potassium chloride 3.6-5.0 Sulfacell 2.0-5.0 Ferrochromlignosulfonate 1.0-2.0 Disolvan 0.5-2.5 Water 59.0-61.5