Crude Oil Transportation Pipeline Research Articles

Investigation of adsorption behaviors of paraffin waxes on iron, iron oxide, and iron III oxide pipeline's internal surfaces using adsorption locator model

Wax deposition in pipelines leads to pressure drop, reduced effective cross-sectional area, and blockages. Although mathematical models and experimental loops were used to model wax precipitation on pipeline surfaces, its prediction at molecular levels is not fully recognized. Molecular dynamics is another powerful approach that can predict wax precipitation at the molecular level. This paper uses molecular dynamics simulations with the adsorption locator model found in Material Studio Software to investigate the adsorption behaviors of Icosane-C20H42, Docosane-C22H46, and Tetracosane-C24H50 paraffin waxes on the Fe, FeO, and Fe2O3 pipeline internal surfaces. Modeling is performed by varying temperature values and validated with experimental data. It was found that as the temperature altered, the adsorption energies, probability energy distribution and adsorption density field on the surfaces also changed; on the other hand, the energetic analysis results showed adsorption energies increase with carbon numbers increase due to its larger surface contacting areas and lower aspect ratio, which resulted in stronger interaction with the surfaces. Further, paraffin waxes showed to adsorb easily on Fe surfaces than oxide surfaces. At temperatures below Wax Appearance Temperature (WAT) on both simulations and experiments showed wax deposition. The lower adsorption energy capacity observed on the Fe2O3 pipeline surface confirms it's vitality and suitability for crude oil transportation pipelines surface lining material.

Corrosion risk assessment using adaptive bow-tie (ABT) analysis

Corrosion is a major threat to safety and asset integrity in oil and gas production and processing facilities. This paper proposes a simple, yet practical model for quantitative corrosion risk assessment from safety and economic perspectives. This includes an Adaptive Bow-Tie (ABT) model for the corrosion risk with a specific focus on microbiologically influenced corrosion, along with corrosion economic risk profile. The ABT model is logically tested using corrosion science and statistically verified using a pipeline corrosion database, including cases of corrosion-induced failures. The ABT model also provides opportunities to run root-cause contribution (RCC) analysis and to estimate the probability of corrosion, corrosion-induced failures, and highly probable sequences leading to failure. The model application is demonstrated using a crude oil transportation pipeline system. The study identifies and quantifies parameters that helps to prioritize the actions needed to prevent and control corrosion and avoid failures. The proposed model can serve as an important mechanism to identify, assess, and manage corrosion threat to an asset.

A data-driven pipeline pressure procedure for remote monitoring of centrifugal pumps

Pumping systems are a key component of oil and gas pipeline transportation assets: monitoring their integrity is a crucial operation from a safety and revenue point of view. The solutions currently employed in the industry apply supervised machine learning techniques to data collected by multi-domain sensors directly installed on several positions of the pump itself; however, such approaches are not applicable on older machines, in contexts where a direct access to the pump is not possible, or whenever labelled data are not at disposal. This paper, instead, presents a predictive maintenance strategy where the condition of a centrifugal pump is tracked by solely exploiting standard pressure measurements, recorded also on remote points along the pipeline, and using an unsupervised learning approach. The smart monitoring strategy is presented and validated on historical pressure signals collected by Eni for several years on a crude oil transportation pipeline, located in Italy. Pressure data, recorded along the fluid line, are used to compute several statistical indicators on appropriate window lengths. These indicators are then fed to an unsupervised clustering procedure, based on a Gaussian mixture model. The output is an index within four different pump operational regimes, and a clustering visualization that permits the interpretation of the automatic regime classification. In fact, the manual inspection of the clusters shows that three of them describe standard modes (regular pumping operation, pumps off, flow regulations). The fourth one corresponds to high amplitude peaks in the signals and indicators, and so it is tagged as “anomalous” mode: pump maintenance logs reveal that the peaks are associated to damaged roller bearing movements, which disappear after the activation of the pump backup system. Anomalies are reported several days before the pump switch, so that a preventive maintenance could have been triggered. The robustness of the clustering algorithm is assessed on a statistical basis, whereas the overall validity of the monitoring system is tested on an instantaneous basis by applying the proposed model on two independent datasets, collected on real transportation pipelines: the results demonstrate the reliability of the proposed monitoring strategy in predicting and detecting all the pump failure events reported by the available maintenance logs. With respect to the mostly employed approaches, our machine learning procedure does not require any previous supervision of the data. Moreover, input data are the pressure transients produced by the pumps and guided within the fluid in the pipeline for long distances: pump failure analysis can be run using sensors located at several kilometers of distance from the pump itself, making a remote control strategy feasible.

Computer-based method of design and modeling of transient flow in crude oil pipeline system

The utilization of computational fluid dynamics tools continue to gain growing interest from pipeline designers and transient flows simulators. Transient flow software with robust graphical user interface (GUI) capable to compute transient flows characteristics and modeling of selection of pipefittings and its associated components are arguably preferred, because of cost effectiveness and straightforward to use. To this aim, in this paper, the utilization of computer-based method for the prediction of transient flow phenomena in crude oil transportation pipelines of 52 km loading and offloading offshore terminal is developed. A transient solver with credible GUI was used for the implementation of design and transient analysis of the crude oil transportation pipeline system. The findings from the simulations provided profound understanding and predictions of transient flows regime in the pipeline that would be relevant to carrying-out risk assessment, control and mitigation on similar tangible pipeline systems. In addition, modified design rules for transient flow assessment, control and risk mitigation of crude oil pipeline at the design stage are presented in a flow chart format.

Fundamental Study of Wax Deposition in Crude Oil Flows in a Pipeline via Interface-Resolved Numerical Simulations

This work presents a fundamental analysis of the mechanisms governing wax deposition and removal in crude oil transportation pipelines. We utilize a numerical framework where oil and deposit are tr...

Experimental and numerical study on dynamic scaling mechanism of glass fiber reinforced plastics pipeline

The test and evaluation method of dynamic scaling for crude oil transportation pipeline under oil field environment has been presented based on self-developed dynamic scaling testing device, by which the dynamic cyclic fouling experiments of GFRP pipeline under transportation condition have been conducted, and the dynamic amount of scale has been obtained under different temperatures, fluid velocities, exposure times and metal ions. Secondly, the effects of temperature, fluid velocity and exposure time on dynamic scaling rate of GFRP pipeline have been analyzed from macroscopic perspective by using grey correlation method, by which the correlations between dynamic scaling rate of GFRP pipeline and those factors are obtained. Thirdly, SEM and XRD are used to investigate surface morphology, composition and structure of scale from microscopic perspective, by which the effect of metal ion on the scaling mechanism has been analyzed qualitatively. Finally, based on experimental results, the structure model of Ca6−xMgx(CO3)6 and Ca6−xFex(CO3)6 has been established by using materials studio, and the elastic property parameters of different structure model have been calculated, by which the effect of metal ions on scaling mechanism has been investigated quantificationally. Dynamic scaling mechanism of GFRP pipeline is revealed and the corresponding anti-scaling measure is presented.

Investigation of the relative abundances of single-core and multicore compounds in asphaltenes by using high-resolution in-source collision-activated dissociation and medium-energy collision-activated dissociation mass spectrometry with statistical considerations

Asphaltenes cause multiple problems in the petroleum industry, such as clogging crude oil transportation pipelines and fouling catalysts. Characterization of the structures of the compounds in asphaltenes is essential for addressing these problems. Two main categories of asphaltene molecular structures, single-core (island) and multicore (archipelago), have been agreed upon. However, their relative abundances in asphaltenes have been debated for decades. This may be partially due to the fact that many mass spectrometry studies carried out in both academia and industry make conclusions for the entire asphaltene sample based on information derived from a group of ionized asphaltenes with m/z values ranging from one up to ten. This approach makes the unvalidated assumption that the relative abundances of single- and multicore compounds are uniform within the entire sample. In this study, medium-energy collision-activated dissociation (MCAD) in a linear quadrupole ion trap/orbitrap high-resolution mass spectrometer was employed to explore the structures of asphaltene molecular ions with m/z values in the ranges of 350 ± 10, 450 ± 10, 550 ± 10 and 650 ± 10. The ions studied displayed different extents of decrease in their weighted average ring and double bond equivalence (RDBE) values when undergoing dissociation, suggesting that the abundances of single-core and multicore compounds are not uniform within the entire asphaltene samples. Therefore, traditional mass spectrometry approaches used to determine the relative abundances of single- and multicore asphaltene compounds may suffer from a sampling bias. However, in-source collision-activated dissociation (IS-CAD) is not susceptible to sampling bias because no ion selection is involved.

Discussion on Design of Flow Assurance for High Pour Point Crude Oil Transportation Pipeline

Flow assurance is very important for design and operation management of the high pour point crude oil transportation pipeline. This paper choose one oil pipeline of CNOOC as an analysis example. Research on two main design plan according to the thermal management mode. In the heating, hot water preheating and displacement plan, the best temperature of hot water is existed. Hot water 88°C will be adopted. The greater of the preheating water flowrate, benefits thepreheating. The design flowrate 6359m3/d will be used. In skin effect electric heat plan, the pipeline insulation layer thickness of 80 mm and skin heating power of 2534 kw will be used through technical economical comparison, and the advantage of skin effect electric heat plan is analyzed relative to heating, hot water preheating and the displacement plan. The above research results may provide technical reference for the future design of high pour point crude oil transportation pipeline.

Pressure Wave Elimination in Iraqi Crude Oil Pipelines Using Novel Porous Filter and Electronic Control System

The pressure wave is a serious problem in crude oil transportation pipelines. It is generated at the beginning and at the end of crude oil pumping process or as a result of sudden closing of valves. The high turbulence fluid particles in presence of pressure wave resulting in sever stresses on pipe walls needing for maintenance and replacement after a period of time. It is also leading to dissipation of flow energy consuming much more power for oil pumping. The objective of the present work is to decrease and eliminate the pressure wave in Iraqi crude oil pipelines through designing, manufacturing, and testing of a novel pressure wave filter with optimum design. The experimental system consists from: porous filter, oil pipe, pump, AC drive, and digital pressure transducers. The porous filter that was tested to eliminate the pressure wave is composed from various pipes (0.5 inch Perspex pipe, 1 inch PVC pipe, and 2 inches stainless steel pipe) with different porous materials to absorb the pressure energy from the fluid particles. These porous media are (1.5cm, 1cm, 0.4cm glass beads, and glass cylinders of 2cm length, 2cm outer diameter, and 2mm thickness). The experimental results proved the successful of the invented porous filter for eliminating the pressure wave by 99% using optimum design without suppressing the flow rate of crude oil in the pipe. The results obtained are quite significant since it awards a simple and low-cost solution for a real and practical problem in crude oil transportation sector.

The study on temperature field variation and phase transition law after shutdown of buried waxy crude oil pipeline

In the buried waxy crude oil pipeline, considering the change of physical properties with temperature and the latent heat of wax precipitation, based on the pipeline-soil-atmosphere coupled heat transfer, the temperature drop model after shutdown is established by apparent heat capacity method. Taking a waxy crude oil transportation pipeline in Daqing Oilfield as an example, under different initial oil temperatures, different environmental temperatures and different soil thermal conductivities, the distribution of temperature field in pipeline and soil is simulated, the influence mechanism on temperature field of these three cases is analyzed. In addition, the phase transition interface of wax precipitation in crude oil is traced, the variation law of interface position after shutdown is analyzed. This research could provide a theoretical basis for the establishment of pipeline shutdown engineering scheme.

Phenomenological study on heat and mass coupling mechanism of waxy crude oil pipeline transport process

ABSTRACTBased on the phase equilibrium model of the paraffin wax precipitation in the process of oil pipeline transportation, theory and method of non-equilibrium thermodynamics were applied to obtain the linear phenomenological equations for the cross-interaction of heat and mass transfer during pipeline transport, which were derived from the irreversible entropy production rate equation. Then, the analysis of the irreversible heat flow and the mass flow were carried out, and the mathematical expressions of the phenomenological coefficient of liquid phase, the phenomenological coefficient of solid phase flow, and the heat flow phenomenological coefficient were obtained. Taking a waxy crude oil transportation pipeline in Daqing Oilfield as an example, based on the analysis of liquid–solid phase equilibrium, the irreversible linear phenomenological mechanism of heat and mass coupling in waxy crude oil pipeline transportation was analyzed in detail from three levels: phenomenological coefficients which reflect characteristic of the effect of force on flow in heat and mass transfer; thermodynamic forces which trigger heat and mass transfer; transmitted heat and mass flow density, providing a theoretical basis for the further study of the wax deposition in the process of pipeline transportation.

Enhancing the efficiency of crude oil transportation pipeline: a novel approach

In this paper, exergy and economic analyses are carried out on a 30″ crude oil transportation pipeline and related pump stations. The exergy destructions and losses of the components and the entire system were determined in the operation, resulting in the identification of the gas turbines stacks as the major elements of exergy losses. A proposal has been made for improving the energy and exergy efficiencies of the entire system. It has been shown that transfer of heat recovered from hot flue gas to the crude oil (for warming up the crude oil) can reduce the viscosity and flow resistance of the crude oil in the transportation pipelines, which could lead to a reduction in the power consumption and transportation costs. By applying this method, the energy and exergy efficiencies of the system will increase by up to 36.40 and 23.23%, respectively.

Study of pressure and temperature developing profiles in crude oil pipe flows

Pressure and temperature developing profiles for crude oil transportation pipelines are simulated under a diversity of external boundary conditions. MOLCV is used in this research to convert a system of partial differential equations into a system of ordinary first order differential equations in cylindrical coordinates. Momentum and energy balance equations are coupled in crude oil flows because of thermal–physical property variations. Simulation solutions show the effect of boundary conditions in the pressure drop profile, which provide potential model predictive applications to account for weather forecast in crude oil transportation operations.