Laboratory assessment of the efficiency of corrosion inhibitors at oilfield pipelines of the West Siberia region I. Objective setting

This paper continues a series of publications dedicated to lab assessment of efficiency of carbon dioxide corrosion inhibitors at the oilfield pipelines of West Siberia region. It reviews the results of tests performed on "rotating cylinder" and "rotating cage" facilities. The article reviews the effect of temperature, specimen surface condition, flow velocity, presence of a hydrocarbon phase and inhibitor concentration on corrosion rate and protective properties of a wide range of commercial inhibitors. Recommendations on specific inhibitor test conditions are given to assess their applicability for protection of water lines, oil pipelines with low watercut and oil pipelines with high product watercut. Key words: corrosion inhibitors, test methods, oilfield pipelines.Received: September 1, 2013. doi: 10.17675/2305-6894-2013-2-4-287-303 Previously [1 -3], the specifics of tests in glass U-cell, flow-through recirculation loop, and bubble method have been studied to assess the efficiency of carbon dioxide corrosion inhibitors. This paper reviews the potential of another two methods for inhibitor testing that according to [4 -9] are quite accurate in simulation of the corrosion scenario in oilfield pipelines, namely, the rotating cylindrical electrode and rotating cage methods. The potential of these methods was analyzed by the example of the same inhibitors as in the previous articles [1 -3], so the numeration of the inhibitors accepted there is kept unchanged. Inhibitors No. 3, 4 and 7 are qualified by the manufacturers as imidazolines and No. 5 is a quaternary ammonium base. Inhibitor No.1 is a mixture of quaternary ammonium bases and imidazoline derivatives. Inhibitors No. 2 and 6 are amines. ExperimentalThe rotating cylindrical electrode method involves measuring the corrosion rates (K) of a steel cylinder rotating at a certain rate in corrosive liquid media placed in an air-tight electrochemical cell. The K values were estimated on the basis of specimen mass loss and by the polarization curve method [10]. At least five parallel experiments were made in each test fluid.

Section: Methodsmentioning

confidence: 99%

Laboratory assessment of the efficiency of corrosion inhibitors at oilfield pipelines of the West Siberia region V. Rotating cylinder and cage

Gedvillo¹,

Oleinik²,

Sivokon³

et al. 2013

“…Figure 1 shows the calculated values of C w for CI featuring different values of ζ and water content % in transported oil. In practice, most common corrosion inhibitors applied to protect pipelines from internal corrosion [1] are soluble and can be easily dispersed in water, with ζ ranging from 1 to 10 or more. The graph demonstrates that such CIs are more effective when a higher water cut fluid of over 80% is transported, since C w is almost equal to C z delivered to the pipeline.…”

Section: Materials Balance Field Application Continuous Treatmentmentioning

confidence: 99%

“…Let's return to equation (1). Listed below are the factors reducing the CI concentration in the water and oil phase:…”

Section: Materials Balance Field Application Continuous Treatmentmentioning

confidence: 99%

Material balance of corrosion inhibitors. Distribution at lab testing and field application

Sivokon¹

2013

This article may produce an impression that it deals with low priority issues of pipelines corrosion inhibitor protection processes and corrosion inhibitors (CI) lab testing techniques. However, it is proved that clear understanding of CI active molecules location makes it possible to identify the causes of CI inefficiency and can be used to produce recommendations to adjust lab testing and CI efficiency evaluation techniques. Inadequate attention paid to the CI distribution material balance may result in:-Wrong choice of CIs at lab tests -Excessive or insufficient concentration selection to ensure required protective action at field applications A series of recommendations is proposed by the author based on a discussion and review of the cases described in the article. Research guidelines are proposed as knowledge of CI properties is essential to overcome current shortcomings.

“…The bubble test is a popular method for assessment of corrosion inhibitors used at oilfield pipelines [1][2][3][4][5]. It is characterized by low shear stresses and simulates the corrosion situation not to the full extent even at water lines and oil pipelines with low watercut where the fluid flow velocity is small [5]. However in many cases, this method can allow one to get familiar with the numerous commercial chemicals and to reject the worst efficient ones among them.…”

mentioning

confidence: 99%

Laboratory assessment of corrosion inhibitors effectiveness at oilfield pipelines of West Siberian region. III. Bubble test

Andreev¹,

Anufriev²,

Sivokon³

2013

Self Cite

This article continues a series of publications dedicated to lab assessment of carbon dioxide corrosion inhibitors efficiency at the oilfield pipelines of West Siberian region. Results of the bubble test are reviewed. The effect of temperature, test duration, condition of the specimen surface, the presence of a hydrocarbon phase, and concentration of inhibitors on corrosion rate and protective properties of a wide range of commercial inhibitors are analyzed. Recommendations on specific test conditions to assess the applicability of inhibitors for protection of water lines and oil pipelines with low watercut are given. The bubble test is a popular method for assessment of corrosion inhibitors used at oilfield pipelines [1][2][3][4][5]. It is characterized by low shear stresses and simulates the corrosion situation not to the full extent even at water lines and oil pipelines with low watercut where the fluid flow velocity is small [5]. However in many cases, this method can allow one to get familiar with the numerous commercial chemicals and to reject the worst efficient ones among them. The purpose of this paper is to assess the capability of this method in ranking of carbon-dioxide corrosion inhibitors for the West Siberian region and determine the test conditions that ensure the most accurate results. We addressed these tasks using the same commercial inhibitors as in [6] as examples. The numbering of inhibitors used in that study was also kept unchanged. Inhibitors No. 3, 4, and 7 are qualified by the manufacturers as imidazolines and No. 5 as a quaternary ammonium base. Inhibitor No. 1 is a mixture of quaternary ammonium bases and imidazoline derivatives. Inhibitors No. 2 and 6 are likely to be amines. Key words: corrosion inhibitors, test methods, oilfield pipelines. ExperimentalDuring the tests, we measured the corrosion rate (K) of steel electrode sensors (by the linear polarization resistance method, LPR) and flat steel specimens (by the mass loss method) placed in the test fluids through which carbon dioxide was slowly bubbled.