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Aqueous solution and method for use thereof

a technology of hydrochloric acid and solution, applied in the field of high-concentration hydrochloric acid (hcl) solution with urea, can solve the problems of reducing the properties of previously available solutions,

Inactive Publication Date: 2017-01-19
SCHLUMBERGER TECH CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The patent text describes a composition that can be used to inhibit corrosion of steel exposed to acidic environments. This composition includes water, hydrochloric acid, and two fixing agents (urrea or urea derivatives). The first fixing agent:hydrochloric acid ratio is between 0.4 and 3.0, and the second fixing agent can be either urea or urea derivatives. The composition can be used in various applications such as in oil and gas wells, where steel casings and formations are often exposed to acidic environments. The technical effect of this composition is to provide a safer and effective means to prevent corrosion of steel in these environments.

Problems solved by technology

HCl above 15% was determined to be deleterious to the properties of previously available solutions.

Method used

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  • Aqueous solution and method for use thereof
  • Aqueous solution and method for use thereof

Examples

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Effect test

example 1

[0038]A 15 wt % solution of HCl was prepared by diluting 37 wt % HCl with urea (FA1) and water. Corrosion tests were performed during which the HCl solution was tested alone, with FA1, and with FA1 and FA2. The solutions were heated to 93° C. (200° F.) during which a steel coupon was immersed in each solution for four hours. The results are presented in Table 1.

TABLE 1Corrosion test results: N80 steel; 93° C.; 4 hAcid FormulationCorrosion ResultsFA1 / HClCorrosion(molarInhibitorPittingRateFluidratio)FA2aidIndex(lb / ft2)15% HClN / AN / AN / A30.699015% HCl + Urea1N / AN / A30.463515% HCl + Urea10.1%N / A10.0068

[0039]Compared to the control solution of 15% HCl, the presence of FA1 alone at an FA1 / HCl molar ratio equal to 1 reduced the corrosion rate by more than 33%; however, the corrosion rate was significantly higher than 0.05 lb / ft2. Satisfactory corrosion inhibition was observed by adding a small amount of FA2.

example 2

[0040]A 15 wt % solution of HCl was prepared by diluting 37 wt % HCl with urea (FA1) and water. Corrosion tests were performed during which the HCl solution was tested alone, and with a mixture of FA2 and inhibitor aid. The solutions were heated to 135° C. (275° F.) during which a steel coupon was immersed in each solution for four hours. The results are presented in Table 2.

TABLE 2Corrosion test results: N80 steel; 135° C.; 4 hAcid FormulationCorrosion ResultsFA1 / HClCorrosion(molarInhibitorPittingRateFluidratio)FA2aidIndex(lb / ft2)15% HClN / AN / AN / A40.648415% HCl + Urea0.4N / AN / A40.106615% HCl + Urea0.40.1%0.4%00.0091

[0041]The presence of FA1 at a molar ratio FA1 / HCl=0.4 reduced the corrosion rate more than six fold compared to a solution of 15% HCl alone. However, the corrosion rate remained above 0.05 lb / ft2. Satisfactory results were obtained when both FA2 and inhibitor aid were present.

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Abstract

Oilfield treatment compositions contain water, hydrochloric acid at a concentration between 15 wt % and 45.7 wt % and a first and second fixing agent. The first fixing agent comprises urea, a urea derivative or both. The second fixing agent may be a mixture or amines and alcohols. These compositions provide corrosion inhibition when exposed to steel. The compositions may also contain an inhibitor aid.

Description

RELATED APPLICATION DATA[0001]None.BACKGROUND[0002]The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.[0003]The technical field generally, but not exclusively, relates to high-concentration hydrochloric acid (HCl) solutions with urea, and uses thereof. Previously known solutions of HCl with urea, for example as described in U.S. Pat. No. 4,466,893, utilize urea with low HCl concentrations (at or below 15%) and in the presence of various plant-based polysaccharide gums. HCl above 15% was determined to be deleterious to the properties of previously available solutions.SUMMARY[0004]In an aspect, embodiments relate to compositions comprising water at a concentration lower than or equal to 20 wt %, hydrochloric acid at a concentration between 15 wt % and 45.7 wt %, and a first fixing agent comprising urea, a urea derivative or both, and a second fixing agent. The first fixing agent:hydrochloric acid mola...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C09K8/54E21B43/26E21B41/02
CPCC09K8/54C09K2208/32E21B43/26E21B41/02E21B43/28C23F11/04E21B43/27
Inventor JIANG, LILECERF, BRUNOJONES, TIMOTHY G. J.ZIAUDDIN, MURTAZAHUTCHINS, RICHARDHE, JIANLI, JACKKRAEMER, CHAD
Owner SCHLUMBERGER TECH CORP
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