Integrating, Predicting and Preventing Flow Assurance Issues—A Review
01 Jan 2019-pp 941-954
TL;DR: Light is shed on how to plan an integrated approach for the management of the flow assurance problems in a multiphase flow system and the measures that need to be taken during the planning phase of the project.
Abstract: This paper reviews the multiple aspects of flow assurance problems, from a production standpoint, with an aim to provide a deeper understanding of the work that needs to be done to mitigate them. It is seen in multiple case studies that proposed solutions to specific problems do not work well and need to be reinvestigated. Hydrate plugging, wax deposition and asphaltene and scale build-up are typical flow assurance problems. Generally, it has been seen that, under conducive circumstances, these three issues take place in conjunction with each other, which further intensifies the problem; e.g. low temperatures lead to an acceleration of both hydrate formation and rate of wax deposition. An integrated study of the crude with the surrounding conditions would provide a clearer picture, which would help in diagnosing the best possible measure to prevent it. Work done in this paper builds on the initial overview and discusses methods of assessing and analytically predicting flow assurance problems that might arise during the course of the production. Integrating the three issues together and then predicting the problems that might arise would significantly lower the chances of escalation of the situation. From a safety perspective, the paper further discusses the measures that need to be taken during the planning phase of the project, to omit any future situations of such problems once a risk has been identified during the prediction phase. Preventive measures for each of the three flow assurance problems give an integrated outlook of how to tackle these issues together. This paper further sheds light on how to plan an integrated approach for the management of the flow assurance problems in a multiphase flow system.
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TL;DR: In this paper, a comparative study on heat management systems in flowlines was conducted from the top five publishers (Elsevier, Springer, Taylor & Francis, Wiley, and Sage) based on the number of publications to determine the level of work done by researchers in the last decade, the figures from the study showed the need for scientific research in the field of active heating.
Abstract: The enormous cost of handling the challenges of flow assurance in subsea wells, flowlines, and risers, especially in deepwater applications, has necessitated a proactive approach to prevent their risk of occurrence. To ensure that transportation of the hydrocarbon is economical and efficient from the subsea wellhead to the processing units, a flow assurance heat management system is relevant in the design and planning of a fluid transport system. Consequently, the advancement of new technologies to serve the increasing need by exploring the technologically challenging and hostile subsea fields is of great importance. A comparative study on heat management systems in flowlines was conducted from the top five publishers (Elsevier, Springer, Taylor & Francis, Wiley, and Sage) based on the number of publications to determine the level of work done by researchers in the last decade, the figures from the study showed the need for scientific research in the field of active heating. Additionally, a review was implemented to ascertain the likely advantages and drawbacks of each technique, its limitations concerning field applications and then recommend suitable cost-effective technique(s). The active heating system gives the most cost-effective solution for subsea deepwater fields.
20 citations
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TL;DR: In this paper, a simple method to screen crude oils for their tendency to precipitate asphalt, which may cause problems during production, is described, based on a thermodynamic model of asphalt solubility, derived earlier by Flory and Huggins.
Abstract: This paper describes a simple method to screen crude oils for their tendency to precipitate asphalt, which may cause problems during production. The method is based on a thermodynamic model of asphalt solubility, derived earlier by Flory and Huggins. The most important parameters in this model are the Hildebrand solubility parameters for oil and asphaltene, and their molar volumes. The oil parameters can all be correlated with the in-situ density of the crude. It is shown that heavy crudes usually will give fewer problems with asphalt precipitation, despite their higher asphaltene content, certainly if the reservoir pressure is close to bubblepoint pressure. Consequently, the tendency for asphalt precipitation is mainly determined by three parameters: the extent to which the crude is undersaturated with gas, the density of the crude at reservoir conditions, and its saturation with asphalt at downhole conditions. Apart from the simple screening method, more elaborate methods are described to assess the potential for asphalt precipitation more accurately; asphaltene analysis on produced reservoir fluid and tank oil; n-heptane titration of the tank oil; visual inspection of a bottom-hole sample in a high-pressure cell during pressure reduction; and dynamic flow tests on tank oil after n-heptane addition.
267 citations
01 Jan 2002
138 citations
TL;DR: In this paper, a unified approach to evaluation of asphaltene precipitation based on laboratory measurement and modeling is presented, which uses an organic deposition cell (ODC) for measuring the dropout onset conditions.
Abstract: A unified approach to evaluation of asphaltene precipitation based on laboratory measurement and modeling is presented. This approach uses an organic deposition cell (ODC) for measuring asphaltene-dropout onset conditions. Asphaltene precipitation was detected by changes in optical fluorescence, electrical conductance, and visual observation. A series of experiments measured the effects of changing pressure,m temperature, and composition on asphaltene precipitation. A fully compositional vapor/liquid/solid (V/L/S) mathematical model completed by analysis by matching the experimental results. The authors then used the model to forecast asphaltene precipitation under a variety of production scenarios, including response to gas-lift operations,and to evaluate the possible location of a tar mat.
47 citations
TL;DR: In this paper, a comprehensive study has been carried out not only to establish less frequent and more effective remedy than the current action but also to evaluate a future risk of gas injection.
Abstract: An offshore carbonate oil field in the Arabian Gulf is exhibiting asphaltene deposition problem mainly inside tubing of production wells completed in one of two main producible limestone reservoirs This problem significantly reduces well profitability due to production loss and frequent asphaltene removal job (solvent soaking) Furthermore, future full-field EOR development, namely gas injection, is now planned and might have a risk to enhance the asphaltene problem Therefore, comprehensive study has been carried out not only to establish less frequent and more effective remedy than the current action but also to evaluate a future risk of gas injection The study was initiated with careful review of the fundamental measurements, collected during the 20 years production history, of asphaltene properties, ie SARA (saturates, aromatics, resins and asphaltenes) analysis, asphaltene contents, AOP (asphaltene onset pressure) measurement, etc Subsequently, the mathematical modeling analysis using those properties was incorporated into the study in order to develop APE (asphaltene precipitation envelope) for better understanding/predicting of asphaltene precipitation behavior Therefore, this paper describes the integration/optimization of the APE modeling based on all available laboratory data, and consequently suggests representative APE The APE model validity was evaluated by comparison with actual observation data in the problematic reservoir Based on the mathematical models once established, several sensitivities, namely mixing with injection gas and blending oils produced from two main producible reservoirs, were investigated in order to assess impacts of the future EOR on asphaltene risk from sub-surface and surface point of views Several types of injection gas were examined, and their risks were compared and identified Consequently, the surface facility design was adequately modified and optimized in order to minimize asphaltene risk assisted by gas injection
29 citations
29 Oct 2002
TL;DR: In this paper, the predictive local composition model is used to predict both wax appearance temperature and the amount of wax precipitated at varying temperatures with or without detailed n-paraffin analyses.
Abstract: A number of wax models currently in use by the oil industry are based on parameters that were empirically determined to match available data for black oils. These data are often not very precise. The recently developed predictive local composition model is, however, a predictive, theoretically well-defined model based on highaccuracy thermodynamic data. The paper describes how the predictive local composition model can be used in conjunction with conventional cubic equations of state to perform wax equilibrium calculations for black oils. Examples are given that show how the model can predict both wax appearance temperature and the amount of wax precipitated at varying temperatures with or without detailed n-paraffin analyses. The examples presented include the effect of pressure on live oils. The improved thermodynamic modeling of wax formation will allow for better prediction of wax deposition rates for flow assurance.
24 citations