RU2047757C1 - Composition for treatment of well bottom hole area of formation - Google Patents

Abstract

FIELD: oil producing industry. SUBSTANCE: composition for treatment of well bottom hole area contains (% mass): nitriletrimethylphosphonic acid 0.005-0.150, dichloride-bis-(N, N-dimethyl-N-carbodecoxymethyl-N-ethylene ammonium) sulfide 0.1-0.5, and water the rest. EFFECT: lower interphase tension at boundary with oil. 1 tbl

Description

 The invention relates to the oil industry, in particular to compositions for processing the bottom-hole zone of the formation, and can be used for primary and secondary opening.

 It is known to use water-based washing liquids, for example, a clay solution for drilling a reservoir with subsequent lowering of the production string, uncoupling of the layers by cementing and perforation [1] The disadvantage of these washing fluids is that during the opening of the reservoir there is contamination due to filtering out the liquid phase (filtrate) from the washing liquid, which penetrates deep into the reservoir, contributes to the swelling of clay particles there, the increase in their volume, which leads to a narrowing of the pore channels and a decrease in the permeability of the reservoir. In addition, the filtrate, interacting with highly saline water, forms water-oil emulsions and insoluble salts in the form of precipitation, which also helps to reduce the permeability of the bottom-hole zone and the selection of oil from production wells.

 The closest in technical essence and the achieved result to the proposed one is a composition for treating the bottom-hole zone containing an aqueous solution of hydrochloric acid and a surfactant in the following ratio of components, vol.

Saline
acids (12.5-24.0%) 80-90
Oxyethylated isononyl-
phenol with 6 M ethylene oxide AF ₉ -6 10-20
The composition allows you to slightly increase the efficiency of hydrochloric acid treatments by stabilizing the process of dissolution of carbonate rocks. The disadvantage is that its effectiveness is achieved with a relatively high content of scarce, expensive reagents.

 In addition, the low cleaning efficiency of the near-bottom zone occurs due to the small penetration depth of the composition, because it has a high reactivity, high viscosity, the ability to hold in suspension the reaction products (dissolution), which, when accumulated, are able to precipitate and additionally plug the formation. As a result of the manifestation of these properties, the composition is not able to effectively displace the mud filtrate and the drilling mud itself from the pores and cracks of the reservoir and hydrophobize its surface, i.e. create conditions for an effective influx of oil, and cannot be used in both primary and secondary autopsy.

 The aim of the invention is to increase the efficiency of the composition by reducing its reactivity, viscosity and surface tension, as well as reducing material costs through the use of inexpensive reagents.

 This is achieved by the described composition for treating the bottom-hole formation zone containing acid, surfactant and water.

 What is new is that nitrilotrimethylphosphonic acid (NTP) is used as the acid, and dichloride bis- (N, N-dimethyl-N-carbodecoxymethyl-N-ethylammonium) sulfide (thionium) is used as a surfactant. in the following ratio of components, wt.

Nitrilotrimethylphosphonic
acid 0.005-0.15
Dichloride bis- (N, N-dimethyl-
N-Carbodeoxymethyl-N-Ethylene
ammonium) sulfide 0.1-0.5.

 It is known to use thionium as a biologically active anti-inflammatory substance used in veterinary medicine, as well as in the oil industry as an additive in cement mortars in order to improve physicomechanical properties aimed at the quality of well attachment.

 In the proposed composition, thionium plays the role of an additive that has a positive effect on the efficiency of cleaning the bottom-hole zone of the productive formation, allows to increase the production rate of production wells, as well as reduce the time for their development.

 From the foregoing it follows that the proposed composition meets the criteria of the invention "significant differences".

The proposed composition is a true solution, with a density of 1.01-1.05 kg / m ³ and a viscosity of 1.1-1.6 MPa s, pH 6.5-5.0.

The following materials were used to prepare the compositions:
Nitrilotrimethylphosphonic acid (NTP) is powdery, white, soluble in water. TU 6-92-11-71-79; Dichloride-bis- (N, N-dimethyl-N-carbodo-eksoxymethyl-N-ethyleneammonium) sulfide (thionium) pasty, light brown, soluble in water. TU 88.USSR 192-092-88;
Technical water (tap). GOST 4979-49.

The compositions were prepared as follows: the calculated amount of NTF and thionium was introduced into industrial water, mixed until they were completely dissolved, and water was added to a predetermined volume. Then, in freshly prepared solutions, the interfacial tension (σ dyne / cm ² ) was determined at the boundary of the studied oil solutions by the stalagmometric method on a device of the Ufa Research Institute design. A stalagmometer consists of a micrometer sensor, with which a drop of oil is squeezed out, a syringe containing oil and a capillary, a drawn, sharpened tip of which is placed in a glass with the test solution. The capillary is pre-calibrated and its constant (K) is determined. For calibration, “pure” liquids are used, for example, hexane-distilled water. To measure the interfacial tension of the investigated solutions used oil Romashkinskoye field with a density of 0.830 kg / m ³ . Interfacial tension was determined by the formula
σ K˙ V _sr ˙ Δ ρ where σ is the interfacial tension, dyne / cm ² ;
K is the capillary constant, s ^-2 ;
V _cf. the average volume of a drop of oil in the test solution (in 10 measurements) cm ³ ;
Δ ρ the density difference of the test solution and oil, kg / m ³ .

 We have tested 6 formulations of the proposed composition and one known.

 In laboratory conditions, pure solutions (initial components) included in the composition of the components were also tested for effectiveness.

 Studies have shown that NTF solutions have only a destructive effect, and thionium solutions only have a hydrophobic, wetting effect. However, their joint presence in the composition has a synergistic effect, in which simultaneously wetting, hydrophobization and destruction of clay particles bonds occurs, which helps to achieve this goal.

 The test results are shown in the table.

 From the results given in the table it follows that the content of thionium in an amount of 0.1 wt. is lower (composition 6), and 0.5 wt. upper limits (composition 9), allowing to achieve the highest positive results in terms of the goal. A further increase in the thionium content is impractical, since the magnitude of the interfacial tension does not change significantly, and the quantitative content is optimal, corresponds to the minimum cost (compared with the prototype) in cost, is low viscosity, which contributes to deeper penetration into the depth of the reservoir and effective displacement from the pores and cracks in the filtrate of the drilling fluid and the drilling fluid itself, effectively cleans the bottomhole zone, and also causes an additional influx of oil.

Claims (1)

 COMPOSITION FOR PROCESSING A BOTTOMFLOUR ZONE OF THE PLASTIC, containing acid, a surfactant and water, characterized in that nitrilotrimethylphosphonic acid is used as the acid, and dichloride-bis- (N, N-dimethyl-N-carbodeoxymethyl- N-ethyleneammonium) sulfide in the following ratio of components, wt. Nitrilotrimethylphosphonic acid 0.005 0.15
Dichloride bis- (N, N-dimethyl-N-carbodecoxymethyl-N-ethyleneammonium) sulfide 0.1 0.5
Water Else

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