Effectiveness of corrosion inhibitors used in oil and gas fields

Abstract

The reliability of assessment of the effectiveness of oil-and gas-field equipment protection by inhibitors depends on the method employed. Assessments based on results received by several methods make it possible to Fred a set of inhibitors that are the most effective for each specific fieM and to develop the most optimal technology for their application.In accordance with the established standards [1][2][3], the effectiveness of inhibitors under industrial conditions is assessed as follows:--in gravimetric method: from the loss of the mass of the control samples placed in a stream of the product being recovered;--in electrochemical method: by using a corrosion meter and transducers placed in the pipelines; --in analytical method: from the change of iron ion concentration in the aqueous part of the product being recovered;--from the number of breaches (total and specific) in the pipelines due to corrosion; --from the state of the surface of the metallic equipment being protected and its actual service life. Practically speaking, each of these methods has its limitations, which are often ignored in practice. The gravimetric method is the most popular and is almost always employed for preliminary assessment of inhibitor effectiveness in specific oil-and gas-field environments. Note that this method allows determination of the average rate of uniforha corrosion of the samples over the testing time, and only from the results obtained by this method can we assess the suitability of a particular inhibitor in specific situations.

Finding an effective way to inhibit carbon dioxide corrosion of ferrous metals in oil-and-gas production media

“…According to the presently developed concepts concerning the mechanisms of carbon dioxide corrosion, the effective inhibiting effect can be produced by inhibitors of the cathodic or mixed type, with predominant hindrance of the cathodic process [35,36]. At the same time, inhibitors of the anodic type (KhOSP, OR-2K, GIPKh-3, etc.)…”

“…Such an action, determined by the difference between the adsorption properties of inhibitors on a clean metal surface and on corrosion products, depends on their concentration in the corrosive medium [56,57]. It was shown in [9,10,35,36] that film-forming inhibitors with a cathodic type of action, which contain a carbonyl or carboxyl group, are universal as applied to the carbon dioxide corrosion. They can be used both on a clean metal surface and on that covered with a carbonate-oxide film or a layer of deposits.…”

“…These inhibitors include organic substances containing a carboxyl and a carbonyl groups (cyclic ketones, ethers, and esters) [47,35,36]. The efficiency of inhibitors with respect to the carbon dioxide corrosion was studied in a wide range of pH values, 2310.…”

“…At the optimal, from the standpoint of adsorption, relative contents of components, the strongest increase in b c was observed. It has been established that the KRTs reagents are inhibitors of the blocking type [35,36,45]. Presumably, the reaction between the components of the formulation in the adsorption layer yields molecular compounds forming a protective film that precludes penetration of depolarizers (HCO 3 !…”

Adsorption and corrosion inhibition of amphiphilic compounds on steel pipeline grade API 5L X52 in sulphuric acid 1 M

“…They generally reduce the corrosion rate by blocking of the anodic and/or cathodic reaction. Several kinds of them had been used through the time [7][8][9]. Due to their characteristics, amphiphilic compounds have been used has CI [10][11][12], therefore in the present study, the efficiency of seven amphiphilic compounds for the inhibition of steel API 5L X52 corrosion in a 1 M H 2 SO 4 solution was investigated.…”