RU2443747C1 - Method for obtaining reagent for drilling fluid - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method for obtaining reagent for drilling fluid involves treatment of lignosulphonate with sulphuric acid and bichromate of alkali metal to pH 1-1.5 with further partial neutralisation by means of sodium hydroxide to pH 4-5; drying. At the specified treatment there introduced is sulphide-alkali drain - waste of petrochemical activities, which contains 6-8 g/l of sulphide sulphur, in quantity of 25-30 parts by weight.

EFFECT: reducing the contamination of waste water with connections of hexatomic chrome.

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Description

The invention relates to the field of oil and gas industry and can be used in the manufacture of reagents for drilling fluids.

A known method of preparing a stabilizing reagent for processing clay solutions by the interaction of lignosulfonates with alkali metal bichromate in an acidic environment, where in order to accelerate the oxidation reaction carried out in the cold, salts having the ability to increase acidity in an aqueous solution are added in powder form. The reaction mixture is diluted with water and the resulting products are canned by adding the original lignosulfonates. As such salts, acidic salts of inorganic polybasic acids, for example phosphoric, or salts of strong acids and weak bases, for example iron sulfate, are used (AS USSR. No. 546642, class C09K 7/00, 1974). The composition has an effective reduction in the loss of clay.

The disadvantage of this method is the cost of the product due to the significant consumption of acid salts, comprising 10-25 wt.% From the content of dry lignosulfonates.

A known method of preparing a lignosulfonate reagent for the treatment of drilling fluids, including the interaction of lignosulfonate with alkali metal bichromate at 80-90 ° C in an aqueous medium, moreover, condensed sulfite-alcohol bard (KSSB) is used as lignosulfonate, and alkali metal dichromate is used in an amount of 0, 5-1.0 wt.% By weight of the KSSB (A.S. USSR No. 1491878, class C09K 7/00, 1986). The reagent provides high heat resistance and low filtration into the formation when drilling high-temperature horizons.

Closest to the proposed invention is a method for producing a drilling reagent, comprising treating the lignosulfonate with sulfuric acid and an alkali metal bichromate to a pH of 1-1.5, followed by partial neutralization with sodium hydroxide to a pH of 4-5, drying, and when the lignosulfonate is oxidized with alkali metal dichromate to a reaction the zone is introduced by wastewater generated during drying of the target product. Wastewater is an aqueous solution of lignosulfonate containing a residual amount of unreduced chromium compounds in the range 0.50-0.65 wt.h. (Patent RU 2375404, class C08L 97/02, 2008). The method is as follows: lignosulfonate is loaded into the reactor - 100 parts by weight, waste water - 30 parts by weight (based on the amount of lignosulfonate), the reaction mass is mixed, then sodium dichromate is introduced - 4-5 parts by weight, sulfuric acid 15-20 parts by weight, the components are further mixed. The technological process takes 3 hours at a pH of 1-1.5. The resulting mass is neutralized with sodium hydroxide to a pH of 4-5 and dried to a powder state. The method allows the use of lignosulfonates of various grades, to increase the rate of fluidization of the drilling fluid and reduce the loss of sodium dichromate.

The disadvantage of this method is the rather significant consumption of an expensive reagent - alkali metal dichromate, the difficulty of maintaining the oxidation of components in an optimal mode, which leads to pollution of wastewater with toxic hexavalent chromium compounds.

The purpose of the invention is the reduction and optimization of the method of obtaining a reagent for drilling mud.

This goal is achieved in that in a method for producing a reagent for a drilling fluid, comprising treating lignosulfonate with sulfuric acid and alkali metal bichromate to pH 1-1.5, followed by partial neutralization with sodium hydroxide to pH 4-5, drying, when processing lignosulfonate with alkali metal bichromate sulfide-alkaline runoff is introduced into the reaction zone in an amount of 25-30 parts by weight, containing 6-8 g / l of sulfide sulfur (S ^2- ). Sulphide-alkaline runoff (SSS) is a waste of petrochemical production and is formed during the operation of plants for primary oil refining, catalytic cracking, hydrotreating, gas fractionation. SSS has the following composition: sulfide sulfur (S ^2- - 6-8 g / l, petroleum products - 0.03-0.5 g / l, phenols - 0.005-0.25 g / l, pH value 7.5-8 ,5.

A positive effect is achieved due to the fact that the sulfide-alkaline runoff contains a significant amount of sulfide sulfur, which has a large reducing ability and ensures the complete reduction of hexavalent chromium to compounds of trivalent chromium Cr ⁺³ . Salts of trivalent chromium Cr ^{+3 are} more effective for the formation of a complex compound with sodium lignosulfonate - the main substance of the drilling fluid reagent. This allows the use of sulphide-alkaline runoff as a cheap reductant reagent, eliminating the pollution of wastewater with toxic hexavalent chromium compounds.

The proposed method is as follows:

The following are loaded into the reactor:

Sodium lignosulfonate -100 parts by weight

sulfide-alkaline runoff - 25-30 parts by weight

alkali metal dichromate - 1.30-1.35 parts by weight

sulfuric acid - 15-20 parts by weight

As the alkali metal bichromate, sodium dichromate or potassium dichromate is used.

The technological process is carried out for 3 hours with stirring of the reaction mixture at pH 1-1.5. Next, the resulting mass is neutralized with sodium hydroxide to a pH of 4-4.5 and dried to a powder state. A drilling fluid reagent, conventionally called HLS-M, is obtained.

Qualitative characteristics of the target product were determined by the indicators of dilution, solubility of the reagent for the drilling fluid in water.

According to the table, it is seen that upon receipt of the reagent for a drilling fluid based on lignosulfonate, the introduction of sulfide-alkaline runoff in the range of 25-30 wt.h. provides a high dilution rate (54.2-56.2%, the prototype - 52-56%, at a rate of at least 40%), good solubility of the reagent in water (92.0-93.4% at a rate of at least 90% ) The use of sulfide-alkaline runoff in an amount of less than 25 parts by weight leads to a decrease in the quality characteristics of the drilling reagent, there is a decrease in the rate of dilution and solubility in water (table 1, experiment 2). In addition, with a low consumption of SCW, the wastewater generated during product drying contains hexavalent chromium compounds. The use of sulfide-alkaline runoff in an amount of more than 30 parts by weight not advisable, since it leads to reagent overruns while reducing the quality characteristics of the target product (table 1, experiment 11). With a decrease in the content of sulfide sulfur in the SHS of less than 6 g / l, hexavalent chromium compounds appear in wastewater. With an increase in the content of sulfide sulfur in the SHS of more than 8 g / l, the resulting product has lower indicators of dilution and solubility in water (Table 1, experiments 6, 10).

Claims (1)

A method of producing a drilling fluid reagent, comprising treating the lignosulfonate with sulfuric acid and an alkali metal bichromate to a pH of 1-1.5, followed by partial neutralization with sodium hydroxide to a pH of 4-5, drying, characterized in that, during said treatment, sulfide is additionally introduced into the reaction zone alkaline runoff is a waste of petrochemical production containing 6-8 g / l of sulfide sulfur, in the amount of 25-30 wt.h.