Standard friction prediction model of long-distance hot oil pipelines

We developed a predictive model for the pipeline friction in the 520-730 m^3/h transmission range using the multi-layerperceptron-back-propagation(MLP-BP)method and analyzing the unit friction data after the pigging of a hot oil pipeline.In view of the shortcomings of the MLP-BP model,two optimization methods,the genetic algorithm(GA)and mind evolutionary algorithm(MEA),were used to optimize the MLP-BP model.The research results were applied to the standard friction prediction of three sections of a hot oil pipeline.After the GA and MEA optimizations,the average errors of the three sections were 0.0041 MPa for the GA and 0.0012 MPa for the MEA,and the mean-square errors were 0.083 and 0.067,respectively.The MEA-BP model prediction results were characterized by high precision and small dispersion.The MEABP prediction model was applied to the analysis of the wax formation 60 and 90 days after pigging.The analysis results showed that the model can effectively guide pipe pigging and optimization.There was little sample data for the individual transmission and oil temperature steps because the model was based on actual production data modeling and analysis,which may have affected the accuracy and adaptability of the model.

Characteristics of the active-layer under the China-Russia Crude Oil pipeline

Active layer is a key component for permafrost environment studies as many subsurface biological,biogeochemical,ecological,and pedogenic activities prevail in this layer.This study focuses on active layer temperature monitoring in an area with sporadic permafrost at two adjacent sites along China-Russia Crude Oil Pipeline(CRCOP),NorthEast China.Site T1 is located in disturbed ground on the right-of-way(on-ROW)2 m away from the center of the oil pipeline.T2 is located in a natural and undisturbed site,around 16.6 m off-ROW.Our objective was to study seasonal variability of the active layer depth and thermal regime from October 2017 to September 2018.The monitoring sites consist of soil temperature probes arranged in a vertical array at different depths at both sites.The following parameters were computed:number of isothermal days(ID),freezing days(FD),thawing days(TD),freezing degree days(FDD),thawing degree days(TDD),number of freeze-thaw days(FTD).The mean air temperature in the monitoring period reached-3.2℃.The temperature profile indicates that the maximum active layer thickness observed during the study period was 10 m at T1 and 2 m at T2.The majority of the soil temperatures were above or close to 0℃,resulting in great values of TDD,especially in the first 4 m depth.TDD for T1 were predominant and ranged between 600-1160℃·days(0-4 m depth)reflecting the influence of oil temperature from the pipeline.In T2 borehole FDD were predominant for all the soil layer depths resulting in less permafrost degradation.This comparison emphasizes the significant influence of vegetation removal and the dispersed heat from the pipeline on the active layer thickness.

WAVELET TRANSFORM THRESHOLD NOISE REDUCTION METHODS IN THE OIL PIPELINE LEAKAGE MONITORING AND POSITIONING SYSTEM

This letter investigates the wavelet transform, as well as the principle and the method of the noise reduction based on wavelet transform, it chooses the threshold noise reduction, and discusses in detail the principles, features and design steps of the threshold method. Rigrsure, heursure, sqtwolog and minimization four kinds of threshold selection method are compared qualitatively, and quantitatively. The wavelet analysis toolbox of MATLAB helps to realize the computer simulation of the signal noise reduction. The graphics and calculated standard deviation of the various threshold noise reductions show that, when dealing with the actual pressure signal of the oil pipeline leakage, sqtwolog threshold selection method can effectively remove the noise. Aiming to the pressure signal of the oil pipeline leakage, the best choice is the wavelet threshold noise reduction with sqtwolog threshold. The leakage point is close to the actual position, with the relative error of less than 1%.

Centrifuge model test on performance of thermosyphon cooled sandbags stabilizing warm oil pipeline buried in permafrost

The thaw settlement of pipeline foundation soils in response to the operation of the first China-Russia Crude Oil Pipeline along the eastern flank of the northern Da Xing'anling Mountains in Northeast China was simulated in a physical model test(with a similitude ratio of 1/73) in a geotechnical centrifuge. Two pipes of a supported and an unsupported section were evaluated over a testing period for simulating 20 years of actual pipeline operation with seasonal cyclically changing oil and ambient temperatures. The results show that pipe settlement of the supported pipe was 45% of settlement of the unsupported pipe. Settlement for the unsupported section was approximately 35% of the thaw bulb depth below the initial pipe elevation, only 30% of that for the supported pipe due to the influence of the supports. The final thaw bulbs extended approximately 3.6 and 1.6 times of the pipe diameter below the unsupported and supported pipe bottom elevations, respectively. The sandbag supports kept frozen during the test period because of cooling effect of the thermosyphons. The maximum bending stress induced over the 20 m span length from bearing of the full cover over the pipe would be equivalent to40% specified minimum yield strength(SMYS). Potential buckling of the pipe should be considered as the ground thaws.This study also offers important data for calibration and validation of numerical simulation models.

DISTRIBUTED OPTICAL FIBER SENSOR FOR LONG-DISTANCE OIL PIPELINE HEALTH

A fully distributed optical fiber sensor （DOFS） for monitoring long-distance oil pipeline health is proposed based on optical time domain reflectometry （OTDR）. A smart and sensitive optical fiber cable is installed along the pipeline acting as a sensor, The experiments show that the cable swells when exposed to oil and induced additional bending losses inside the fiber, and the optical attenuation of the fiber coated by a thin skin with periodical hardness is sensitive to deformation and vibration caused by oil leakage, tampering, or mechanical impact. The region where the additional attenuation occurred is detected and located by DOFS based on OTDR, the types of pipeline accidents are identified according to the characteristics of transmitted optical power received by an optical power meter, Another prototype of DOFS based on a forward traveling frequency-modulated continuous-wave （FMCW） is also proposed to monitor pipeline. The advantages and disadvantages of DOFSs based on OTDR and FMCW are discussed. The experiments show that DOFSs are capable of detecting and locating distant oil pipeline leakages and damages in real time with an estimated precision of ten meters over tens of kilometers.

Study on the Economic Insulation Thickness of the Buried Hot Oil Pipelines Based on Environment Factors

It is important to determine the insulation thickness in the design of the buried hot oil pipelines.The economic thickness of the insulation layer not only meets the needs of the project but also maximizes the investment and environmental benefits.However,as a significant evaluation,the environmental factors haven’t been considered in the previous study.Considering this factor,the mathematical model of economic insulation thickness of the buried hot oil pipelines is built in this paper,which is solved by the golden section method while considering the costs of investment,operation,environment,the time value of money.The environmental cost is determined according to the pollutant discharge calculated through relating heat loss of the pipelines to the air emission while building the model.The results primarily showed that the most saving fuel is natural gas,followed by LPG,fuel oil,and coal.The fuel consumption for identical insulation thickness is in the order:coal,fuel oil,LPG,and natural gas.When taking the environmental costs into account,the thicker the economic insulation layer is,the higher cost it will be.Meanwhile,the more pollutant discharge,the thicker the economic insulation layer will be.

Cold-region environments along the China-Russia Crude Oil Pipeline and their management

The cold-region eco-environments along the China-Russia Crude Oil Pipeline (CRCOP) in northern Northeast China are in disequilibrium due to the combined influences of pronounced climate warming and intensive anthropogenic activities.This is evidenced by the sharp areal reduction and northward shifting of the boreal forests,shrinking of wetlands,enhancing of soil erosion,accelerating degradation of permafrost and deteriorating of cold-region eco-environments.The degradation of permafrost plays an important role as an internal drive in the eco-environmental changes.Many components of the cold-region eco-environments,including frozen ground,forests,wetlands and peatlands,forest fires and 'heating island effect' of rapid urbanization,are interdependent,interactive,and integrated in the boreal ecosystems.The construction and long-term operation of the CRCOP system will inevitably disturb the cold-region environments along the pipeline.Therefore,a mandatory and carefully-elaborated environ-mental impact statement is indispensable for the proper mitigation of the ensued adverse impacts.Proper management,effective protection and practical rehabilitation of the damaged cold-region environments are a daunting,costly and long-term commitment.The recommended measures for protection and restoration of permafrost eco-environments along the pipeline route include adequate investigation,assessment and monitoring of permafrost and cold-region environments,compliance of pipeline construction and operation codes for environmental management,proper and timely re-vegetation,returning the cultivated lands to forests and grasslands,and effective mitigation of forest fire hazards.

Analysis of Offshore Oil Pipeline Floating Laying

-Based on the calculation model for the floating laying of the offshore oil pipeline, this paper analyses in detail the internal force, and deformation of the pipeline under a definite structural form (pipeline and buoy) and the way of pulling. The obtained results can be used for the buoy deployment, structure design, and the determination of pulling parameters (the pulling force of the cable and its length, etc.), providing an effective analysis method for floating pipeline-laying. A calculation example is given to show the related calculation process and the main results are analyzed and discussed.

An experimental study of the fracture propertiesof oil pipeline girth welds

The application of fracture mechanics to the “Fitness For Purpose” assessment of the fracture properties of pipeline girth welds is generally essential for the safe operation of oil pipeline systems. Based on the analysis of the fracture toughness requirements of the oil pipeline girth weld, a systematic study has been conducted on the fracture behavior of the API 5L X65 steel pipeline girth weld made by two welding materials. The critical COD values of the pipeline girth weld under the different temperatures are tested. In the paper other influential factors on fracture behavior are also discussed, such as the welding materials, the welding positions (flat welding, vertical welding, overhead welding), the welded joint area (weld, heat affected zone, fusion line and base metal) and the experiment temperature. The result shows that the welding material, the welded joint area and the experiment temperature have considerable influence on the fracture behavior of pipeline girth welds. It is also concluded that the effect of the welding position is related to the welding process. The study provides a scientific basis for the welding of oil pipelines.

Simulating Error-Opening of Pressure Relief Valves of a Station on a Continuous Undulating Oil Pipeline with Large Elevation Difference

For oil pipeline in mountain areas,high hydrostatic pressure in the pipeline may cause error-opening of pressure relief valves,and oil is discharged from the pipeline to the pressure relief tanks,bringing spilling-over risk of the pressure relief tanks.Therefore,simulating the error-opening situations of the pressure relief valves and investigating the oil discharge process are necessary for checking the possibility of the spilling-over accident and then proposing measures to improve the pressure relief system.This research focuses on a continuous undulating oil pipeline with large elevation difference and a station along this pipeline,which is named B station in this paper,is studied.By OLGA software,simulation model of the pressure relief system of B station is established,and the accuracy of the model is verified by reconstructing a real accident and making a comparison with the actual accident data.The maximum discharge rate reached 8284 m3/h when the pressure relief valve was opened by mistake in the inlet and outlet of the station.The accumulated filling time of the two pressure relief tanks is 200 s,which is in good agreement with the accident data.On this basis,for error-opening of the pressure relief valves at the inlet and outlet of B station,simulation is performed to investigate variations of the discharge velocity,discharge flow rate,accumulated discharge volume and ventilation volume of the vent valve.The discharge velocity is found to be over the maximum velocity allowed for safety consideration.According to the accumulated discharge volume,it is inferred that spilling over of the pressure relief tanks will be caused once error-opening of the pressure relief valve occurs.Also it is judged that the existing breathing valve can not satisfy the ventilation requirement in case of failure of the pressure relief valves.From these simulation results,it is proposed that increasing the number of vent valves,replacing the manual valves with electrically operated valves,and employing security control interlock protection program are improvement measures to guarantee safe,efficient and reliable operation of the pressure relief system at B station.

Numerical Study and Economy Analysis of Two Heated Crude Oil Pipelines Laid in One Ditch

In this paper,the transportation economy of two heated crude oil pipelines laid in one ditch is analyzed by taking into account the influence of operating temperature,interval between two pipelines,and distance between two heating stations on the heating energy consumption.To analyze the transportation economy,the two heated crude oil pipelines laid in one ditch are simulated under four operating conditions based on an unstructured finite volume method.Compared with laying two crude oil pipelines separately in two ditches,the results attest notably higher soil temperature,meaning reduced heat dissipation of each pipeline by laying two pipelines in one ditch.It is inferred that for the same desired oil temperature at the inlet of the next heating station,laying two pipelines in one ditch requires lower oil temperature at the outlet of heating station,indicating decreased energy cost at the heating station and improved transportation economy.Then economy analysis of four configurations of laying two pipelines in one ditch is performed.By comparing the results of four conditions,the interval between two pipelines of 1.2 m is found to save the energy most efficiently,which is as large as 26.6%compared with that of laying two pipelines in two separate ditches.In addition,narrowing the pipeline interval and extending the distance between heating stations is beneficial to save heating energy.This study is expected to provide valuable guidance for operation optimization of heated crude oil pipelines.

China, Bangladesh sign framework agreement on oil pipeline project

The Bangladeshi government signed a framework agreement with China for construction of a 220-km pipeline to carry oil from tankers in the Bay of Bengal to storage plants on Chinese mainland.Bangladesh’s Economic Relations Department(ERD)Secretary Kazi Shofiqul Azam and Chinese Ambassador to Bangladesh Ma Mingqiang signed the framework agreement in

Prediction on Failure Pressure of Pipeline Containing Corrosion Defects Based on ISSA-BPNNModel

Oil and gas pipelines are affected by many factors,such as pipe wall thinning and pipeline rupture.Accurate prediction of failure pressure of oil and gas pipelines can provide technical support for pipeline safety management.Aiming at the shortcomings of the BP Neural Network(BPNN)model,such as low learning efficiency,sensitivity to initial weights,and easy falling into a local optimal state,an Improved Sparrow Search Algorithm(ISSA)is adopted to optimize the initial weights and thresholds of BPNN,and an ISSA-BPNN failure pressure prediction model for corroded pipelines is established.Taking 61 sets of pipelines blasting test data as an example,the prediction model was built and predicted by MATLAB software,and compared with the BPNN model,GA-BPNN model,and SSA-BPNN model.The results show that the MAPE of the ISSA-BPNN model is 3.4177%,and the R2 is 0.9880,both of which are superior to its comparison model.Using the ISSA-BPNN model has high prediction accuracy and stability,and can provide support for pipeline inspection and maintenance.

Analysis of the harmful effects to buried oil pipeline from power line short-circuit fault

Based on the transmission line theory of the buried metallic structures, the concerned harmful effects to the buried oil and natural gas pipelines caused by the power line short-circuit fault are further discussed. A closed-form expression of the induced voltage caused by the short-circuit fault of the ultra-high voltage power （UHVAC） transmission line is given. The transmission line model of the buried pipeline is set up and a set of formulas for calculating induced voltage on the pipeline and the parameters of the buried pipeline in actual environment condition are given. At last, the characteristic of the harm^hl effects on the buried pipeline from the power line short-circuit fault are discussed.

Review analysis on cloud computing based smart grid technology in the oil pipeline sensor network system

Natural resources plays efficient contribution in the human world in the way of consuming energy resources for the daily life cycle.The main concerns rely on the transporting oil from refining to the consumer usages through different modes.In the transportation passages,its performances are calibrated in the robust manner through sensor network communication and the periodical pigging inspection on the pipeline system.This chapter enumerates about the layout of oil pipeline system and its sensor measurement and instrumentation deliberately placed on the long run pipelines.The evolution of smart grid application enhances this oil transportation in a much corporate band by accumulatively orienting the sensor network in the utilization of power resources.Further,through the wireless communication associated with the smart grid,the pigging inspection gauges are exploited in the desired geographical area with better power consumption.Existing research on communication technologies in SG is briefly overviewed with the main focus on Cloud computing approaches.In this paper,the Smart Grid architecture and its applications are focused on entire oil pipeline from inlet to distribution substations first.The Cloud Computing architecture is explained thoroughly.Then,Cloud Computing for Smart Grid applications are also introduced in terms of efficiency,security and usability.Cloud platforms technical and security protocols are analyzed.Finally,the inspection of oil pipeline system by receiving sensor data of smart pigs incorporated with the cloud computing technique associated with smart grid application is elaborated with its SCADA hierarchical architecture.Further,simulation analysis of wireless sensor nodes with Flexmeter platform for power monitoring over smart pig case scenario is also presented with its layer-wise characterization.

THE RISK ASSESSMENT OF THE LONG-DISTANCE OILPIPELINE ENGINEERING

The oilfield construction and long-distance oil pipeline engineering has been developed extensively in China. The risk assessment of oil industry will, however, be an important objective to cope with the development of oil industry , The risk assessment of oil industry has many subjects worthy to be studied.The major purpose of the paper is to research the risk cases of long-distance oil pipeline engineering in Ganshu and Shaanxi provinces.

Miniaturized antenna design for communication establishment of peer-to-peer communication in the oil pipelines

In the oil pipeline world,wireless automation plays an important role through integrated electronic technology in antenna design for robust performance.The technology gets evaluated by its power consumption and compactness to afford a better solution to real-world problems with better sophistication to adopt a modernized wireless world.Among that,the IoT(Internet of Things)technology plays a predominant role by combining with Artificial Intelligence to optimize and revolute the characterization of data communication.When the data communication is initiated,the main contributor to the transmission is the miniaturized antenna holding different types in its structure and processing.It acquires the required radio spectrum channel with the advanced multi coding modulating technique by utilizing token ring mesh topology for the data transfer with acquired data channels.This chapter describes the design and fabrication of a miniaturized antenna using MEMS technology(Micro-Electro-Mechanical System)and its different types using INTELLISUITE software to get suited for better communication in oil pipelines.Based on the application,it also enumerates the choices of micro or nanoantennas with its specification upholding data adopting techniques with modulation schemes to support IoT applications.

Improving Crude Oil Flow Using Graphene Flakes under an Applied Electric Field

Graphene flakes(GF)have been prepared and assessed as a material for improving flow in oil pipelines under the effect of an electric field.In particular,different amounts of GFs have been considered in order to determine the optimal flow conditions.The GFs were prepared from graphite foam,derived from the dehydration of sugar with a particle size of 500-600μm,which was dispersed in ethanol and exfoliated in a ball mill under a shear force.After 15 h of exfoliation,sonication,and subsequent high-speed centrifugation at 3000 rpm,irregular-shaped GFs of 50-140 nm were produced and characterized using scanning electron microscopy,X-ray diffractometry,atomic force microscopy,and Raman spectroscopy.The prepared graphene sheets have been found to display excellent morphology and good graphitic structure.Experiments on flow improvement were conducted using the central composite rotatable design method for three parameters:stimulation time(15,30,45,and 60 s),applied voltage(150,170,200,and 220 V),and concentration of the GFs(0,100,200,and 400 mg/L).The optimal conditions for improved crude oil flow were then determined using the STATISTICA and WinQSB software packages.The results have confirmed the effectiveness of the use of the prepared GFs as a flow improver for crude oil,where the flow improvement is essentially a result of a reduction in viscosity and suppression of friction in the crude oil system.