This paper starts a series of publications dealing with the laboratory assessment of the performance of corrosion inhibitors for oilfield pipelines. Typical corrosion and inhibitor protection conditions in oilfield pipelines of the West Siberia region and existing approaches to the laboratory simulation of corrosion situations in oilfield pipelines are discussed. The simulation conditions and capabilities of laboratory test methods are compared.

This paper is a continuation of a series of publications related to laboratory assessment of the performance of carbon dioxide corrosion inhibitors for oilfield pipelines in the West Siberian region. The test results obtained in U-shaped glass cells are considered. The effects of temperature, carbon dioxide content, test duration, specimen surface condition, presence and volume of a hydrocarbon phase, and inhibitor concentration on the corrosion kinetics and protective properties of a wide range of industrial inhibitors are analyzed. Recommendations are given on specific inhibitor test conditions to be used for assessment of inhibitor suitability for the protection of water pipelines and oil pipelines with low watercut.

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.

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.

This article continues a series of publications dedicated to lab assessment of the efficiency of carbon dioxide corrosion inhibitors at oilfield pipelines of the West Siberia region. Results of the test in a flow recirculation loop are reviewed herein. The paper highlights the effect of temperature, test duration, oxygen concentration, condition of specimen surface, flow velocity, presence of hydrocarbon phase and inhibitor concentration on the corrosion rate and protective properties of a wide range of commercial inhibitors. The paper gives recommendations on specific conditions for testing inhibitors to assess their applicability for the 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: May 28, 2013May 28, . doi: 10.17675/2305May 28, -6894-2013 The flow recirculation loop test is one of few methods for lab assessment of inhibitor efficiency that makes it possible to simulate oilfield pipelines of almost any type [1]. This can be achieved by generation of a fluid flow with hydrodynamic and thermochemical properties similar to the real environment of pipeline operation, from water pipelines to oil pipelines with water-containing products. In our point of view, such testing is a mandatory stage in inhibitor selection for their piloting in real pipelines. The purpose of this paper is to assess the capability of this method in ranking of carbon-dioxide corrosion inhibitors and define the test conditions that precisely simulate the conditions of oilfield pipeline operation which are critical in terms of the failure rate.Like in [2,3], these tasks were addressed using commercial inhibitors as examples. At the same time, we have kept the previously accepted numeration. Inhibitors No. 3, 4 and 7 are qualified by the manufacturers as imidazolines and No. 5 as a quaternary ammonium base. No. 1 is a mixture of quaternary ammonium bases and imidazoline derivatives. Inhibitors No. 2 and 6 are amines.