Oil Gas Pipelines Research Articles

Control of Aircraft for Inspection of Linear Infrastructure

Inspection aircraft equipped with cameras and other sensors are routinely used for asset location, inspection, monitoring, and hazard identification of oil-gas pipelines, roads, bridges, and power transmission grids. This paper is concerned with automated flight of fixed-wing inspection aircraft to track approximately linear infrastructure. We propose a guidance law approach that seeks to maintain aircraft trajectories with desirable position and orientation properties relative to the infrastructure under inspection. Furthermore, this paper also proposes the use of an adaptive maneuver selection approach, in which maneuver primitives are adaptively selected to improve the aircraft's attitude behavior. We employ an integrated design methodology particularly suited for an automated inspection aircraft. Simulation studies using full nonlinear semicoupled six degree-of-freedom equations of motion are used to illustrate the effectiveness of the proposed guidance and adaptive maneuver selection approaches in realistic flight conditions. Experimental flight test results are given to demonstrate the performance of the design.

Ultra-Long Distance Fiber Bragg Grating Sensor System

A novel tunable fiber ring laser configuration with a combination of Raman amplification and erbium-doped fiber amplification (EDFA) is proposed for realizing high signal-to-noise ratio (SNR), ultra-long distance (300 km) fiber Bragg grating (FBG) sensor systems. The hybrid Raman–EDF amplification configuration can enhance the optical SNR of FBG sensor signals significantly, so the optical power reflected by the fiber Bragg grating can be compensated. A good optical SNR of 15 dB is achieved for a 275 km transmission distance, which is the best performance to our knowledge, and about 4 dB at 300 km. In the static strain experiments with fiber lengths of 100,200,250,300 km, the linearity is greater than 0.999. This system can be widely used in the ultra-long-distance sensing applications such as railways, oil(gas) pipelines and coastline.

A New Type of Pig Handling Trolley

The Pig is an important tool during the process of oil-gas pipeline’s production, replacement, daily operation and management. Its outer diameter is 2% to 5% larger than the inner diameter of pipelines. It stays a clamping state in the pipelines. The fluid pressure difference before and after the Pig push it from the beginning to the end of the pipelines in order to clear all kinds of impurities in the pipelines and detect the internal and external wall corrosion status of the pipelines or achieve other goals. But during the cleaning-up operation, it is difficult for the Pig to get in and out of the pipelines because of its heavy weight. So a Pig and Pigging ball handling trolley is designed in this paper to push and pull the Pig or Pigging ball to get in and out of the Pig launcher & receiver device. This handling trolley will mechanize the Pigging operations, reduce the labor intensity and improve the work efficiency.

Temperature Error Compensation New Method of MFL Sensor to Oil-Gas Pipeline Corrosion Inspection

Magnetic flux leakage (MFL) inspection is a common method for detecting inner corrosions of oil-gas pipelines; the Hall Effect element is the core sensor of MFL inspections. The Hall sensor is sensitive to temperature, so environmental changes will lead to output error of Hall sensors. In order to compensate for temperature errors of Hall sensors, a segment of oil-gas pipeline with diameter 6 inch was taken as a research object. A fusion model including 50 Hall sensors and 1 temperature sensor was built up, and a functional link artificial neural network optimized by the artificial immune algorithm was used to fuse the output data of the multiple sensors. The lab research results show that the artificial immune algorithm can improve training speed and precision of the functional link neural network; the model built up can compensate effectively for temperature errors of Hall sensors and under the conditions of changing temperature, the precision of magnetic flux inspections of pipelines to detect corrosions can be improved significantly.

State of art of seismic design and seismic hazard analysis for oil and gas pipeline system

The purpose of this paper is to adopt the uniform confidence method in both water pipeline design and oil-gas pipeline design. Based on the importance of pipeline and consequence of its failure, oil and gas pipeline can be classified into three pipe classes, with exceeding probabilities over 50 years of 2%, 5% and 10%, respectively. Performance-based design requires more information about ground motion, which should be obtained by evaluating seismic safety for pipeline engineering site. Different from a city’s water pipeline network, the long-distance oil and gas pipeline system is a spatially linearly distributed system. For the uniform confidence of seismic safety, a long-distance oil and pipeline formed with pump stations and different-class pipe segments should be considered as a whole system when analyzing seismic risk. Considering the uncertainty of earthquake magnitude, the design-basis fault displacements corresponding to the different pipeline classes are proposed to improve deterministic seismic hazard analysis (DSHA). A new empirical relationship between the maximum fault displacement and the surface-wave magnitude is obtained with the supplemented earthquake data in East Asia. The estimation of fault displacement for a refined oil pipeline in Wenchuan MS8.0 earthquake is introduced as an example in this paper.

Study of Underground Oil-Gas Pipeline Corrosion Pits Estimation Based on MFL Inspection Method

Abstract The paper presents a new approach for detection of oil-gas pipeline corrosion pit defects in which pipeline magnetic flux leakage (MFL) detection system is adopted. To test the new approach, some artificial pits are fabricated on the surface of oil-gas pipes to simulate different pits happening in practice. The interference eliminating method is introduced for compensation of defected MFL field and helping map extraction from the background. Both qualitative and quantitative methods of identifying erosion pit defects are described in the paper.

Water and Wastewater Pipe Nondestructive Evaluation and Health Monitoring: A Review

Civil infrastructures such as bridges, buildings, and pipelines ensure society's economic and industrial prosperity. Specifically, pipe networks assure the transportation of primary commodities such as water, oil, and natural gas. The quantitative and early detection of defects in pipes is critical in order to avoid severe consequences. As a result of high-profile accidents and economic downturn, research and development in the area of pipeline inspection has focused mainly on gas and oil pipelines. Due to the low cost of water, the development of nondestructive inspection (NDI) and structural health monitoring (SHM) technologies for fresh water mains and sewers has received the least attention. Moreover, the technical challenges associated with the practical deployment of monitoring system demand synergistic interaction across several disciplines, which may limit the transition from laboratory to real structures. This paper presents an overview of the most used NDI/SHM technologies for freshwater pipes and sewers. The challenges that said infrastructures pose with respect to oil and natural gas pipeline networks will be discussed. Finally, the methodologies that can be translated into SHM approaches are highlighted.

Numerical Simulation of Thermal Cycle of In-Service Welding on X70 Steel Gas Pipeline

In-service welding is a kind of important method to ensure the integrality of oil gas pipeline and the thermal cycle of which is significant for repairing. Used SYSWELD to establish model and simulate thermal cycle of in-service welding on X70 steel gas pipeline, compared thermal cycles of in-service welding and air-cooling welding, studied the influence of gas pressure and flow rate on thermal cycle. The result shows that peak temperature of the coarse grain in heat affected zone (CGHAZ) of in-service welding is similar to air cooling welding, but the cooling time of t8/5, t8/3 and t8/1 decreases at certain degree. Peak temperature of CGHAZ of in-service welding doesn’t vary match with gas pressure and flow rate either. t8/5, t8/3 and t8/1 decrease when gas pressure increases. t8/5 varies with the gas pressure linearly. When the pressure is less than 4MPa, t8/3 and t8/1 decrease rapidly while gas pressure increases. When the pressure is more than 4MPa, t8/3 and t8/1 decrease slowly while gas pressure increases. t8/5, t8/3 and t8/1 decrease when the flow rate increases. When gas flow rate is less than 10m/s, t8/5, t8/3 and t8/1 decrease rapidly while flow rate increases. When gas flow rate is more than 10m/s, t8/5, t8/3 and t8/1 decrease slowly while flow rate increases.

Flow regime independent, high resolution multi-field modelling of near-horizontal gas–liquid flows in pipelines

For fully-developed two-phase flows, maps that correlate experimental and semi-empirical expressions for flow regimes are widely used. For calculations of the various important two-phase flow parameters, this in turn requires correlations for various interfacial and wall interaction effects that are flow regime dependent. For many systems of practical interest, however, the evolution of flow regimes (such as slug flow in oil–gas pipelines) is of interest because the development lengths are long and flow regimes may change in regions where pipeline inclination changes due to the terrain. It is shown here that for slow transients in near-horizontal pipes, the one-dimensional multi-field model, when solved with sufficient resolution, does not require flow regimes to be specified or flow regime dependent closure relationships. The formulation predicts the development of flow regimes and various flow parameters without the need for maps, or the need to change closure relationships. To accomplish this, the model includes four fields, i.e. continuous and dispersed liquid, continuous and dispersed gas, as well as a set of appropriate closure relationships from the literature. For the main application considered here, i.e. slow transients in oil–gas pipelines, order of magnitude analyses indicate that certain inertial terms in the model are very small and can be neglected in comparison to the others. Advantage is taken of this to simplify both the structure of the mathematical problem and the solution procedure, which is sufficiently accurate that mass is conserved for each of the four fields. Furthermore, the calculations require high spatial resolution, so a fast, easily-parallelizable numerical procedure has been applied. The results indicate that the development of certain flow regimes, including transitions from bubbly to stratified flow and vice versa, slug flow including slug frequency and length, and the evolution of these parameters along a pipeline are well predicted by the model when compared to experimental data. As part of the validation it is also shown that the model predicts, without need to change closure relationships, flow regimes in fully-developed near-horizontal two-phase flows in good agreement with existing flow regime maps. This suggests that for slow transients in flows for which one-dimensional effects dominate, predictions can be made without requirements for flow regime maps and closure relationships that depend on them.

Federal Pipeline Rate Making: Alternative Approaches of the United States Federal Energy Regulatory Commission

This article provides an overview of the alternative rate making methodologies adopted by the United States Federal Energy Regulatory Commission (FERC) in itsregulation of transportation rates for oil and natural gas pipelines. In 1997, authority over rate making for interstate oil and natural gas pipelines was transferred to the newly created FERC. This article describes the history of interstate pipeline rate making and the transfer of rate making authority to the FERC.The author looks at the innovative pipeline rate making methodologies implemented by the FERC in its regulation of transportation rates for both oil andnatural gas pipelines. The article describes the adoption by FERC of market based rates and a generally applicable indexed rate cap methodology for oil pipelinerate setting. In respect of natural gas pipelines, the legislative requirements and practical realities associated with cost-of-service rate making by FERC aredescribed and FERC’s policies permitting selective discounting, shipper-specific negotiated rates, and market based rates for natural gas pipelines arereviewed.The Commission’s adoption of the alternative rate making methodologies has taken the emphasis off of general rate case litigation as a means of establishingjust and reasonable rates for interstate oil and natural gas pipelines and related facilities. The alternative rate making methodologies also represent a significantdeparture from cost-of-service rate making, with increasing focus on rate flexibility and competition as a means of generating efficiencies for customers of interstate oil and natural gas pipelines.

Vision-Based Monitoring of Locally Linear Structures Using an Unmanned Aerial Vehicle

Inspecting and monitoring oil-gas pipelines, roads, rivers, and canals are very important in ensuring the reliability and life expectancy of these civil systems. An autonomous unmanned aerial vehicle (UAV) can decrease the operational costs, expedite the monitoring process, and be used in situations where a manned inspection is not possible. This paper addresses the problem of monitoring these systems using an autonomous UAV based on visual feedback. A single structure detection algorithm that can identify and localize various structures including highways, roads, and canals is presented in the paper. A fast learning algorithm that requires minimal supervision is applied to obtain detection parameters. The real time detection algorithm runs at 5 Hz or more with the onboard video collected by the UAV. Both hardware simulations and flight results of the vision-based control algorithm are presented in this paper. A fixed wing UAV equipped with a camera onboard was able to track a 700 m canal based on vision several times with an average cross-track error of around 10 m.

Experimental Study of Interference Factors and Finite Element Simulation on Oil-Gas Pipeline Magnetic Flux Leakage Density

Some methods of enhancing oil-gas pipeline magnetic flux leakage (MFL) detection technique are introduced in the paper. Some man-made defects or imperfections on the pipe surface are detected via the axial magnetization inspection vehicle along the pipeline. The magnetic dipole model of corrosion defect is stated and the important interference factors on magnetic flux leakage are analyzed. Finite element method is used to analyze and simulate normal defects on pipe surface, which can attribute to get natural defect MFL signal. The influence of benign pipeline artifacts (valves, welds, tees, flanges, etc.), pipe material and pipe wall, vehicle velocity, defect dimensions and interaction among defects, and so on are studied in detail. The magnetic flux leakage contour images or indication extraction maps are given and presented. These interference factors are compensated and solved. These approaches and results applied in the paper are contributed to the feature extraction and indication of pipeline abnormality. The results suggest that these approaches and conclusions are significantly effective for the pipeline magnetic flux leakage inspection.

A united model for predicting pressure wave speeds in oil and gas two-phase pipeflows

A pressure wave, caused by unsteady operations such as a shutdown or restart, pigging, slug flow or input flow rate transient changes during an oil–gas pipeline transmission, could cause a safety hazard to the whole pipeline system. Because of the compressibility of the gas phase, the changes of interface between the gas and liquid, the momentum and energy transfer between the two-phase and the single-phase to the wall, all make it complicated for predicting the pressure wave speeds for oil and gas two-phase flow in long-distance pipelines. On the basis of the gas–liquid two-fluid model, this paper analyzes the pressure wave propagation for the two-phase flow. Pressure sources of gas–liquid momentum equations are described as the function of the gas–liquid flow velocities, gas void fraction, void fraction gradient and their differentiations, which make the two-fluid model hyperbolic. With the introduction of virtual mass force, the united model for prediction of the pressure wave speeds has been developed. And the gas–liquid Equations of State (EOS) has also been used in the united model, which can analyze the effects of the different system pressures. Important factors, such as the virtual mass coefficient and the gas void fraction, are also discussed. The developed model fits well with the experimental data, and can be used to predict wave speeds for different flow patterns, such as stratified flow, dispersed bubble flow and slug flow.

Exergetic life cycle assessment of hydrogen production from renewables

Life cycle assessment is extended to exergetic life cycle assessment and used to evaluate the exergy efficiency, economic effectiveness and environmental impact of producing hydrogen using wind and solar energy in place of fossil fuels. The product hydrogen is considered a fuel for fuel cell vehicles and a substitute for gasoline. Fossil fuel technologies for producing hydrogen from natural gas and gasoline from crude oil are contrasted with options using renewable energy. Exergy efficiencies and greenhouse gas and air pollution emissions are evaluated for all process steps, including crude oil and natural gas pipeline transportation, crude oil distillation and natural gas reforming, wind and solar electricity generation, hydrogen production through water electrolysis, and gasoline and hydrogen distribution and utilization. The use of wind power to produce hydrogen via electrolysis, and its application in a fuel cell vehicle, exhibits the lowest fossil and mineral resource consumption rate. However, the economic attractiveness, as measured by a “capital investment effectiveness factor,” of renewable technologies depends significantly on the ratio of costs for hydrogen and natural gas. At the present cost ratio of about 2 (per unit of lower heating value or exergy), capital investments are about five times lower to produce hydrogen via natural gas rather than wind energy. As a consequence, the cost of wind- and solar-based electricity and hydrogen is substantially higher than that of natural gas. The implementation of a hydrogen fuel cell instead of an internal combustion engine permits, theoretically, an increase in a vehicle's engine efficiency of about of two times. Depending on the ratio in engine efficiencies, the substitution of gasoline with “renewable” hydrogen leads to (a) greenhouse gas (GHG) emissions reductions of 12–23 times for hydrogen from wind and 5–8 times for hydrogen from solar energy, and (b) air pollution (AP) emissions reductions of 38–76 times for hydrogen from wind and 16–32 times for hydrogen from solar energy. By comparison, substitution of gasoline with hydrogen from natural gas allows reductions in GHG emissions only as a result of the increased efficiency of a fuel cell engine, and a reduction of AP emissions of 2.5–5 times. These data suggest that “renewable” hydrogen represents a potential long-term solution to many environmental problems.

Life cycle assessment of hydrogen fuel cell and gasoline vehicles

A life cycle assessment of hydrogen and gasoline vehicles, including fuel production and utilization in vehicles powered by fuel cells and internal combustion engines, is conducted to evaluate and compare their efficiencies and environmental impacts. Fossil fuel and renewable technologies are investigated, and the assessment is divided into various stages. Energy efficiencies and greenhouse gas emissions are evaluated in each step for crude oil and natural gas pipeline transportation, crude oil distillation and natural gas reformation, wind and solar electricity generation, hydrogen production through water electrolysis, and gasoline and hydrogen distribution and utilization. The results indicate that, when taking into account fossil fuel energy consumption and greenhouse gas emissions, the efficiency of a fuel cell vehicle employing hydrogen from natural gas should be at least 25–30% higher than the gasoline one to be competitive. Wind electricity generation to produce hydrogen via electrolysis, and its application in a PEMFC vehicle, has the lowest greenhouse gas emissions and fossil fuel energy consumption. However, the economic attractiveness of renewable wind technology is shown to depend significantly on the ratio in costs between hydrogen and natural gas; when this ratio is 2:1, a financial investment to produce hydrogen via natural gas is about five times more profitable than to do so via wind energy.

Turkey's Oil and Natural Gas Pipelines System

Turkey's natural gas (NG) production is very small and is almost all imported. Turkish natural gas production in 2000, 23 billion cubic feet (Bcf), met around 4% of domestic natural gas consumption requirements. NG consumption is estimated at around 700 Bcf in year 2002, accounting for around 17% of Turkey's total energy consumption. Turkish natural gas demand had been projected to increase extremely rapidly in coming years. Country oil production is 50,674 barrels per day (bbl/d) of which 46,674 bbl/d was crude oil in 2002. In 2002, oil consumption was 635,000 bbl/d and net oil imports was 584,326 bbl/d in Turkey. Oil provides around 43% of Turkey's total energy requirements.

CERTAINTY IN UNCERTAIN TIMES: CONSIDERING FORCE MAJEURE

Force majeure clauses are particularly relevant to at least two types of oil and gas agreements: operating agreements and long-term contracts. Each type of contract is characteristically exposed to calamitous events that can take many years to manifest. However, force majeure clauses in each type of contract need to reflect the commercial realities and bargain represented by each type of contract.This paper considers whether the types of force majeure clauses that are used in the Australian oil and gas industry would adequately excuse a party relying on them from performing their obligations under a contract in light of some very real 21st century concerns. The beginning of the 21st century has seen remarkable technological development and the creation of a global village where an isolated event in one part of the world can have a significant effect on the entire world. Therefore, the increased likelihood of a terrorist attack against significant infrastructure (eg. an offshore oil rig or gas pipeline) and the emergence of natural phenomena, particularly widespread viral outbreaks such as the SARS virus can have a devastating effect on industry globally, as is being seen in the airline industry. There is some doubt whether standard contract clauses will automatically treat such circumstances as force majeure events.The paper suggests that certain drafting conventions ought to be adopted to address 21st century concerns, and particularly to provide practical solutions for these issues.

Urban infrastructure security

The US energy infrastructure consists of miles of overhead electric transmission lines and underground oil and natural gas pipelines. While the infrastructure is constructed of simple and easily repaired hardware, the ubiquitous nature of the hardware also makes it a convenient target for terrorism. Gas and electric utilities have developed contingency plans to repair damage to their infrastructure regardless of the cause. A disruption in service has the same impact (on the users) regardless of whether the cause is a natural one (hurricane or earthquake) or man-made (terrorist attack). In most cases, these events are random and impossible to predict. Likewise, the response is the same regardless of the initiating event. Fortunately, the loss of service is usually short-term and does not have a national impact. Utilities have focused their attention on better (real-time) monitoring of their networks to shorten the response time after an event rather than focusing on preventing and/or mitigating an attack.

The controversy over the Caspian Sea mineral resources: Conflicting perceptions, clashing interests

ON 29 AUGUST 1995, at the summit meeting of the Turkic states in Bishkek, Kyrgyzstan, Turkey's President Suleyman Demirel explained why Ankara is so interested in having Azerbaijani, Kazakh and Turkmen oil and gas pipelines passing through Turkey. In his words, it was not economic benefits that Turkey was after: rather, Ankara was interested in lessening the economic and political dependence of the Caspian states on Russia. He said: 'It is to their strategic, political and economic benefit to get rid of any dependency. ... Turkey's approach on the oil and natural gas pipelines should be evaluated in this context'.' As Demirel suggested, Turkey's policy regarding the Caspian Sea problem is closely related to the post-Soviet rivalry between Turkey, Russia and Iran over the newly independent Turkic states surrounding the Caspian.2 By mid-1997 Turkey's attempts to play a significant role in the production and export of the Caspian oil seem to have been stalled by Moscow. After its exclusion from the September 1994 Azerbaijan oil contract, Tehran too adopted an antagonistic attitude toward Ankara's involvement, and in 1996 it embraced the Russian thesis on the Caspian Sea's legal status, restricting non-littorals' access to the Sea's mineral resources. The Turks are convinced that neither Russia's nor Iran's policy toward these states is conducive to furthering Turkey's national interests. Ankara believes that Russia is interested in recapturing its former privileged and dominant status in the region, whereas Iran is motivated by a desire to prevent the regional countries from becoming hostile collaborators with the West and with Turkey. The Russians, for their part, are interested in maintaining their sphere of influence in the region. Although various government agencies have different views on how to accomplish this goal, a general tendency in Moscow has been to restrict the involvement of 'outsiders' such as Turkey and the USA in this part of Russia's 'near abroad'. Towards this end Russia has pursued various policies, including the promotion of Russian pipelines as the only feasible means to export the region's oil resources, and disputing the legality of contracts the Caspian states have signed with Western consortia.

Use of geotextiles in earth structures for oil—gas pipelines under west siberia conditions

One of the methods of protection of the earth bed of a backfill for a pipeline as well as of embankments for the purpose of increasing their resisting capacity under complex engineering-geologic conditions (scouring, heaving, collapsibility, etc.) consists in the use of geotextile synthetic materials. Five new constructional schemes have been developed which possess high resisting (ballasting) capacity. Experimental investigations have been carried out to determine the mechanism of operation of the soil in combination with geotextile layers, using a special laboratory installation.