Oil Transmission Pipelines Research Articles

Analysis and optimization design of internal pressure resistance of flexible composite pipe

Flexible composite pipes have the advantages of light weight, corrosion resistance, scale resistance, and low cost compared to carbon steel pipes, and have attracted much attention in the application of onshore oil and gas gathering and transportation systems. Understanding the relationship between the pressure-bearing mechanical properties of composite pipes and their structural characteristics is crucial for guiding their process application. To investigate the mechanical behavior of flexible composite pipes under internal pressure loads, discrete and combined finite element models were established to analyze the stress-strain characteristics of flexible composite pipes. The bursting strength was predicted, and the influence of winding angle and number of reinforcement layers on the pressure-bearing capacity of flexible composite pipes was revealed. The applicability of the two models in the analysis of internal pressure resistance of flexible composite pipes was evaluated using whole pipe strain testing and instantaneous hydrostatic burst experiments. The results showed that the reinforcement layer is the main pressure-bearing layer of flexible composite pipes, and the innermost reinforcement layer bears the highest pressure. The pressure-bearing capacity of flexible composite pipes significantly increases when the winding angle is greater than 53°, and the increase in pressure-bearing capacity slows down when the number of reinforcement layers exceeds 3. Under the combination model, the strain and bursting strength of flexible composite pipes were closer to the experimental results. The study clearly defines the stress-strain characteristics of flexible composite pipes under internal pressure load and the impact of process parameters, providing a basis for the optimization design of single well oil transmission pipelines in Xinjiang oilfield.

Risk-based maintenance strategy for oil transfer pipelines using an intuitionistic fuzzy computational approach

The safety and reliability of oil transfer pipelines are crucial, as pipeline failures can severely affect the environment. As pipeline risk management is dynamic and uncertain, traditional maintenance approaches often fall short. This research paper proposes an Intuitive Fuzzy Computational Approach (IFCA) for oil transfer pipeline maintenance (RBM). To develop a targeted and nuanced maintenance plan, Failure Modes and Effects Analysis (FMEA) is employed. Pipeline equipment is hierarchically organised according to their failure mode criticality, which guides maintenance design. This paper leverages the context of an Interval Valued Intuitionistic Fuzzy (IVIF) environment to streamline the hierarchical classification of oil transmission pipeline instruments. The objectives are threefold: (1) to develop an intuitionistic fuzzy risk assessment model, (2) to design a modified algorithm for maintenance prioritisation, and (3) to develop a decision support system. Additionally, the research incorporates the IVIF-SWARA method to enable flexible adjustments in the alignment of the pipeline instruments. By addressing the specific challenges of oil transfer pipelines, this research aims to contribute to advancing the field of pipeline maintenance and risk management. The proposed RBM strategy, underpinned by the IFCA framework, is expected to enhance pipeline reliability and mitigate the risks associated with pipeline failures. Abbreviations: RBM: Risk-Based Maintenance; IFCA: Intuitionistic Fuzzy Computational Approach; FMEA: Failure Modes and Effects Analysis; IVIF: Interval Valued Intuitionistic Fuzzy; SWARA: Stepwise Weight Assessment Ratio Analysis; RCM: Reliability-Centered Maintenance; RBI: Risk-Based Inspection; CBM: Condition-Based Maintenance; IFS: Intuitionistic Fuzzy Set; HFPR: Hesitant Fuzzy Preference Relation; IVIFPHA: Interval-Valued Intuitionistic Fuzzy Power Heronian Aggregation; MCDM: Multi-Criteria Decision-Making; S C O i : Accuracy Function of Occurrence; S C S i : Accuracy Function of Severity; K ( a ~ ) : Failure Probability Index; L W D : Minimum Allowable Weight of The Failure Detection Index; WS, WO, WD: Weight Assigned to The Failure Outcome; RP V j : Relative Priority Value; OREDA: The Offshore Reliable Data Handbook; IVIFPWHA: Interval-Valued Intuitionistic Fuzzy Power Weight Heronian Aggregation

Dynamic Behavior and Parameter Characteristics of Buried Pipeline in Airports

Buried pipeline, as one of the crucial facilities of airport ground engineering, has been extensively utilized for the transportation of petroleum, natural gas, industrial wastewater, and more. However, there are significant gaps in the research on the dynamic response of buried pipelines in airports under the action of dynamic traffic loads, which severely hampers the design and engineering quality of oil transmission pipelines. This study builds a three-dimensional finite element model to simulate the action of vehicles on the pipe–soil structure with actual loads. Moreover, the current research establishes a dynamic analysis model of pipe–soil interaction to analyze the material damping and load parameters. Using the structural dynamic response equation and Rayleigh damping calculation theory, this study investigates the change law of pipe dynamic stress and influencing factors and presents the recommended values of the parameters related to the pipe–soil interaction. Results are as follows. A damping ratio of 0.05 can enhance the time lag of the dynamic response of the structure and weaken the response peak. For the Rayleigh damping parameters, the viscous damping coefficient [Formula: see text] has almost no effect on the dynamic response of the pipe–soil structure, so it can be disregarded in the calculation. With the increase of the axial weight of the traffic load above the pavement structure, the peak value of each dynamic response quantity of the pipe–soil structure and load magnitude. The suggested value of the dynamic load coefficient of the pipe–soil structure is 1.5. Lastly, the earth pressure and dynamic load coefficients are suggested to take values for different load and axle type cases.

Experimental Evaluation of Kinetic Behavior of Asphaltene Particles: Effect of Temperature, Shear Stress, and Inhibitors

Summary Asphaltene deposits under a variety of temperatures and shear stresses in reservoirs, wells, and crude oil transmission pipelines, and it is currently one of the most serious problems in the oil industry. The size of asphaltene particles strongly affects the deposition rate. The particle size is mainly determined by aggregation rate that depends on shear rate and temperature. Therefore, different shear rates of 127 s–1 and 254 s−1 were applied within Couette flow at 25°C, 45°C, and 65°C, and the particle size was analyzed by using an optical microscope. Crude oil viscosity and asphaltene solubility were determined using a capillary tube viscometer and IP143 procedure, respectively. In this work, the effects of four additives, namely, dodecyl benzene sulfonic acid (DBSA), nonyl phenol (NP), salicylic acid (SA), and benzoic acid (BA), were studied on the aggregation of asphaltene particles in a light crude oil. The additives were chosen based on their functional groups. Moreover, asphaltene functional groups were determined using a Fourier transform infrared (FTIR) analyzer to better understand the behavior of inhibitors in preventing the aggregation of asphaltene particles at different conditions. DBSA, BA, and SA were inhibitors, and NP behaved as a promoter. According to the results, the presence of acidic groups, SO3H in DBSA and COOH in SA and BA, increases the interaction of inhibitor with asphaltene and so reduces the aggregation of asphaltene particles. The stronger acidic group of DBSA improved its performance compared to other inhibitors. Both increasing temperature and increasing shear stress resulted in higher collisions of asphaltene particles and thus lowered the efficiency of inhibitors at a constant concentration.

Stress prediction of heated crude oil pipeline in permafrost region via fully coupled heat-moisture-stress numerical simulation and SVM algorithm

Large diameter crude oil transmission pipelines in unstable permafrost areas have been put into operation in China in recent dozen years. The perennial positive temperature operation of buried heating transmission pipelines leads to freeze–thaw of the soil around pipelines, and the axial stresses generated by thawing settlement of permafrost may induce fracture failure of weld crack. However, there are many shortcomings in existing frozen soil thawing settlement analysis and pipeline stress assessment methods, which makes it difficult to accurately analyze and predict the axial additional stress of pipelines induced by thawing settlement. Based on heat conduction and permafrost thawing consolidation settlement theory, numerical inversion analysis of centrifuge test was conducted to verify the accuracy of the finite element method. The key influencing factors such as wall thickness, insulation layer thickness, buried depth of pipe, and length of thawing settlement zone on the axial stress and strain state of buried pipeline under the condition of double pipe operation of Mo-da line were investigated. The results show that: Pipeline with an insulation layer, larger wall thickness and smaller buried depth is beneficial to improve the bearing capacity of buried pipeline under thawing settlement of permafrost. The axial stress varies nonlinearly with the increase of the thawing settlement zone length. Based on support vector regression (SVR) model, the axial stress prediction model of pipe crown and invert at different positions in the thaw settlement area was proposed and verified by field monitoring data of buried pipeline. The relative error between the prediction results and the field monitoring results is less than 15 %. This study can provide some theoretical support for the structural design of pipelines in thaw settlement area.

Methodology for assessing pipeline failure probability due to a debris flow in the near field

Aboveground transmission oil pipelines can cross debris flow-prone areas. Currently, there are no available methodologies to assess pipeline failure status with the different pipeline arrangements (location, direction, and segment lengths) and different operating conditions. For solving the research gap, this study proposes a novel methodology to simulate the cascade processes of debris flow propagation, the impact of debris flow on pipelines, and pipeline failure. With consideration of different pipeline arrangement and operating conditions. We introduce the polar coordinate system to set up locations and directions scenarios for the first time. Also, we use the 3-D debris flow simulation model (DebrisInterMixing solver in OpenFOAM) coupled with a modified pipeline mechanical model considering operating conditions for the first time. The proposed methodology shows the different trends of pipeline failure probability with the increase of pipeline segment length for the different pipeline locations and directions. The result shows, for the pipelines of 30° the tensile stress has a more moderate increase rate with the increase of pipeline segment length, and the pipeline failure probability keeps 0 at the 5-m location. At 5 m and 15 m locations, the failure probabilities of the pipelines of 60° and 90° start to increase when the segment length is 13–14 m, while for other pipelines the segment length is 17–19 m. The findings of this study can support the decisions of government authorities, stakeholders, and operators for risk assessment, prioritization of hazard mitigation measures and emergency planning, or concerning decisions regarding pipeline siting during the design, routing, construction, operation, and maintenance stage.

Development of polyaniline – TiO2 nano composite films and its application in corrosion inhibition of oil pipelines

Oil and gas industries are the driving force of Oman’s economy and have a relatively diversified wealth among Gulf Cooperation Council Countries. Oil pipelines play an important role in transporting oil and gas from the wellheads to the processing facilities. Corrosion normally results in the deterioration of the pipe material with exposure to the surrounding environment and complete control of corrosion is difficult. Corrosion in oil transmission pipeline would be effectively addressed by introducing conventional corrosion control practices. Most of the conventional techniques are either less effective or too expensive in controlling the deterioration rate of the pipe materials. However, preventative measures may be taken to protect the metal surface from corrosion is a possible way to reduce corrosion. This research work aimed to develop a novel technique utilizing Polyaniline (PANI) and Titanium dioxide (TiO2) nanocomposites to assess its corrosion inhibition effect on mild steel. TiO2 was synthesized by sol-gel process. Polyaniline-Titanium dioxide (PANI/TiO2) nanocomposites were coated on mild steel specimen by dip coating technique. The coated specimen was subjected to stability studies at different environmental conditions and exposure time. The stable thin film coated specimen was employed in the corrosion inhibition studies at various processing environments. The characteristics of TiO2 nanoparticles and PANI-TiO2 thin films were analyzed using Fourier Transform Infra-Red Spectroscopy (FTIR), Energy Dispersive X-Ray analysis (EDX) and X-Ray Diffraction (XRD) and Dynamic Light scattering (DLS). Scanning Electron Microscopy (SEM) was used to visualize the surface morphology and micro structural characteristics of the preformed thin layer. Potentio dynamic test, Atmosphere test and Wet/Dry tests were carried out to investigate the corrosion behaviour of coated and uncoated specimen. The study demonstrates that the Polyaniline – TiO2 composite thin films fabricated using dip coating technique with minimum film thickness could be a feasible solution in controlling the corrosion in oil pipelines with good film stability, high durability, with a cost effective and environmentally friendly approach.

RISK ANALYSIS TECHNIQUES OF OIL AND GAS PIPELINE

The safety of pipelines that transport energy has become an important and controversial issue with the general public. The main hazard for safe transportation of substances is a pipeline failure taken as a loss of its tightness and release of the transported medium to the environment. To perform reliability analysis and estimation of accident risk level, Fault Tree Analysis (FTA) and Event Tree Analysis (ETA) are two graphical techniques used to perform a risk analysis, where FTA represents causes and their probabilities of failures, and ETA represents consequences of a failure event. Failure of oil transmission pipelines was analyzed by fault tree analysis in this project, and the probability of internal corrosion, one of the root causes, has been evaluated by applying the physical reliability model. According to failure modes of pipeline, leakage and rupture, a fault tree of the pipeline was constructed. Minimal cut sets of the fault tree have been shown, and the failure probability of a top event and the important analyses of basic events were evaluated by quantitative analysis. In conventional fault tree analysis, probabilities of the basic events were treated as precise values. At last, the probability of different accident scenarios that may result from failed oil pipeline due to pipe rupture has been estimated.

Diagnosing microbiologically influenced corrosion at a crude oil pipeline facility leak site – A multiple lines of evidence approach

In crude oil transmission pipelines, some parts of the system receive minimal or no fluid flow (‘dead legs’), which can on occasion lead to under deposit corrosion wherein a mixture of sediments, hydrocarbons, water, and microorganisms collectively contribute to an integrity failure. However, the microbial contribution to this phenomenon in crude oil transmission pipelines is poorly characterized. To better understand this process, we used a multiple lines of evidence approach to examine a dead leg failure event using sludge samples collected from at andnear the leak location and from non-corroded areas on the same pipe segment. Chemical analyses revealed elevated levels of acetate, total iron, and FeCO3 at the leak locations compared to non-corroded areas. Electrochemical techniques showed increased evidence for corrosion in leak site samples compared to non-corroded samples, while corrosion coupon analysis revealed many localized pits of up to 20 μm deep in leak location samples compared to fewer pits that were up to 4 μm deep from the non-corroded sample after incubating the samples for 30 days. 16S rRNA gene analysis revealed sulfide-producers, acetogens, and methanogens in all collected samples. The lack of detection of FeS as a corrosion product, no significant differences in sulfate and sulfide concentrations across all samples, and elevated levels of acetate at the leak location suggested that acetogens and/or fermentative bacteria contributed to this pipeline leak. This study highlights the use of a multiple lines of evidence approach that can be used to garner evidence to determine the contribution of MIC to failures in dead leg pipeline segments.

Uncertainties in internal pressure of oil transmission pipelines and implications for the reliability analysis

This study addresses a significant knowledge gap in the reliability-based fitnessfor-service assessment of pipelines, namely the statistical information of the internal operating pressure. To this end, probabilistic characteristics of the internal pressure of an in-service oil transmission pipeline are derived based on minute-by-minute pressure records collected from the discharge and suction ends of a pump station on the pipeline. The arbitrary-point-in-time discharge and suction pressures are found to follow the Johnson SB distribution; the monthly and annual maximum discharge pressures are found to be well represented by a deterministic quantity equal to 90% of the maximum operating pressure, and the monthly and annual maximum suction pressures follow the beta distributions. The autocorrelation and power spectral density functions of the discharge and suction pressures characterized as stationary stochastic processes are also derived from the pressure records. Furthermore, the statistics of the pressure ranges obtained from the rainflow counting analysis of the pressure records are obtained. Two example pipelines are used to examine the implications of the uncertainty in the internal pressure for the reliability analysis of corroding pipelines.

Modeling of Gas Migration in Large Elevation Difference Oil Transmission Pipelines during the Commissioning Process

Oil pipeline construction and operation in mountainous areas have increased in southwestern China, with oil consumption increasing. Such liquid pipelines laid in mountainous areas continuously undulate along the terrain, resulting in many large elevation difference pipe segments. Serious gas block problems often occur during the commissioning process of these pipelines due to the gas/air accumulation at the high point of the pipe, which causes pipeline overpressure and vibration, and even safety accidents such as bursting pipes. To solve this problem, the gas–liquid replacement model and its numerical solution are established with consideration of the initial gas accumulation formation and the gas segment compression processes in a U-shaped pipe during the initial start-up operation. Additionally, considering the interactions of the gas-phase transfer in the continuous U-shaped pipe, and the influence of the length, inclination angle, and backpressure on the air vent process, the gas migration model for a continuous U-shaped pipe is established to predict the gas movement process. Finally, the field oil pipe production data were applied to verify the model. The results demonstrate that the maximum deviation between the calculated pressure during the start-up process and real data is 0.3 MPa, and the critical point of crushing the gas in the pipe section is about 0.2 Mpa. Additionally, the results show that the mass transfer of the gas section in the multi-pipe hydraulic air vent process causes the gas accumulation section to increase in downstream of the pipe. This study’s achievements can provide theoretical guidance and technical support for the safe and stable operation of continuous undulating liquid pipelines with large drops.

Oil transmission pipelines with corrosion defects reinforced by two types of sleeves: comparison efficiency of sleeves

Two segments of transition oil pipeline DN500 and DN700, operating since 1980, were subjected to full-scale pressure testing. In 2000, corrosion defects were found on both pipelines - the two corrosion defects on the outside wall of DN500 pipeline, and the one corrosion defect on the inside wall of DN700 pipeline. Both pipes were sleeve reinforced to increase the safety and reliability of the lines. The DN500 pipeline used the Cold Lock sleeve - the steel sleeve with a composite filling. On the other hand, the DN700 pipeline used the Clock Spring composite sleeve. In 2020, after two decades of operation with sleeve repairs, both pipelines were dug out, removed from operation and used for full-scale pressure testing to determine the residual strength sleeves repairs and to compare the efficiency of the sleeves. The full-scale test included three stages of loading. The first step was continual loading up to the yield strength of pipelines. The second step was the fatigue pressure test at 2-6,3 MPa with a total of 10 000 cycles. The third step was the burst pressure test. The stress-strain behavior was measured with help of strain gauges placed on the pipeline surface and on the surface of sleeves. From strain gauge measurement, it was found that both sleeves still have a remarkable residual strength even after two decades of operation. However, the Cold Lock sleeve has a higher efficiency compared to the Clock Spring sleeve, as it showed lower strains during loading. The test method, procedure and results will be fully discussed in the proposed paper.

Numerical study of geometric parameters effects on the suspended solid particles in the oil transmission pipelines

The innovation of this paper is geometric parameters effects of the oil transmission pipelines on the suspended solid particles. This geometry has been simulated with the Lattice Boltzmann Method based on D2Q9 model for analyzing solid particle tracing, streamlines, solid particle volume fraction, and nondimensional velocity field of fluid flow. These parameters have been investigated in 9 cases of the oil transmission pipelines at two different intensity of fluid flow. The results signified that maximum and minimum ranges of fluid velocity at [Formula: see text] were in case 3 that the oil transmission pipelines with diameter of the pipeline and bending radius, D and 2D, respectively. Also, maximum volume fraction of solid particles at bending radius at [Formula: see text] was in case 3 with diameter of the pipeline and bending radius, D and 2D, respectively. Also, in case 9, solid particles in the oil transmission pipelines were almost symmetrical. Finally, with comparison between figures of solid particles tracing and volume fraction of solid particles, by increasing of the diameter of oil transmission pipelines, the sediment of solid particles was decreased, also, by increasing of the bending radius of oil transmission pipelines, the sediment of solid particles was increased.

Fatigue reliability analysis of dented pipelines

The present study carries out fatigue reliability analyses of oil and gas pipelines containing unconstrained plain-smooth dents under the variable amplitude loading caused by cyclic internal pressure. The API 1156 S-N curve and Miner’s rule are employed to establish the limit state function for fatigue, and the stress concentration at the dent is accounted for based on findings reported in the literature. The reliability analysis is carried out on two pipeline examples containing dents with depths ranging from 2% to 5% of the pipe diameter. The examples are subjected to cyclic internal pressures at the discharge and suction ends of a compressor station on an actual in-service oil transmission pipeline. In the context of the cyclic pressure records considered in the present study, the analysis results suggest that fatigue failure of dents under suction-end pressure cycles is highly unlikely, whereas the probability of fatigue failure of dents under discharge-end pressure cycles can be significant if the diameter-over-wall thickness ratio of the pipeline is large. This study provides a methodological framework to carry out reliability-based fitness-for-service assessments of dented pipelines with respect to fatigue.

Experimental Study of Steel Reinforcement Repair Sleeve on X80 Pipe with Interlayer Defect

This paper introduces characteristics of common repairment method for oil and gas transmission pipeline, especially for steel reinforcement repair sleeve. In this research, an X80 pipe with interlayer defects repaired by steel reinforcement repair sleeve was studied. In order to investigate the repair effect of steel reinforcement repair sleeve for interlayer defects, a hydraulic blasting test and metallographic analysis for repaired pipeline were performed. The result shows that interlayer defect influences the pressure capacity of pipe to a certain degree, however, steel reinforcement repair sleeve could provide an acceptable strengthening to the repaired section.

油气长输管道焊接方法及焊材用量计算

油气长输管道焊接方法及焊材用量计算

Study on corrosion mechanism and its influencing factors of a short distance intermittent crude oil transmission and distribution pipeline

Based on the characteristics of short transmission and distribution distance, large fluctuation angle and intermittent operation, the corrosion of pipelines of crude oil storage and transportation unit transporting crude oil to refinery processing units in refineries is unique. In this paper, field data collection, fluid simulation analysis and coupon simulation experiments were carried out to study the corrosion of oil pipelines. It was found that sulfate reducing bacteria (SRB) corrosion induced by scaling on the surface of the pipeline was the main mechanism leading to the continuous corrosion perforation of the pipeline, and its induced tendency was related to the chemical composition of the bottom water of the tank and the oil flow rate. Furthermore, if the water had a strong tendency to scale, increasing the oil flow rate would increase the tendency of SRB. The inhibitor was not suitable for controlling the corrosion of this type of pipeline, since it only increased the scaling tendency and the risk of SRB would increase.

Numerical and experimental study on a bypass pig motion in oil transmission pipeline: a case study

In the oil and gas industry, pipeline networks can be used to transport oil and petroleum products from production center to the consumption center. Regular cleaning and inspecting these pipelines is necessary due to the presence of oil deposits. Typically, pigging operation can be applied to clean and inspect of these pipelines. It is important that the velocity of a pig during its passage in the oil pipeline be controlled. Therefore, it is necessary to identify accurately the fluid flow around the pig in order to describe and evaluate the pigs’ motion. In this study, the computational fluid dynamics (CFD) approach has been applied to model fully turbulent flow around a sample of bypass pig and measure its dynamic velocity. This study tried not only to study the pig motion, but also to investigate the parameters affecting the bypass pig pressure drop and then the optimal state of these basic parameters in the design of a pig is determined. Finally, a numerical analysis of the pig motion is performed for a case study of a 20-ih pipeline to transport of gas oil between Rafsanjan, Yazd and Nain located in Iran and compared with the field test results. The results indicated that the fluid passing through the bypass, the weight and contact force had a significant effect on the pig’s speed, and when bypass diameter was larger, leading to the greater fluctuations.

Optimal Operation of Subsea and Onshore Oil Transmission Pipeline

Peng, S.-B.; Liu, Y.; Xu, L.; Zhu, Q.-Y., and Amizi M., 2019. Optimal operation of subsea and onshore oil transmission pipeline. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 475–479. Coconut Creek (Florida), ISSN 0749-0208.Pipeline is one of the most important means of oil and gas transportation, more and more subsea pipelines have been built these years. As the subsea and onshore crude oil transmission pipelines were laid many years ago, the oil pump combination schemes are complicated, which leads to high energy consumption and excessive cost in the pipeline operation. Concerning this problem, based on parameters of the pipeline and crude oil, an economical operation mathematical model for continuous transportation crude oil pipelines is set up, which taking the minimum energy consumption as the objective function, the pump combination scheme and inlet temperature of heating station as the decision variables. According to the characteristics of the model, Tabu search algorithm is used to solve the mathematical model, and an optimization software is developed by C program. Based on actual operating data, the operation scheme of a crude oil pipeline is optimized by the software. Comparison of energy consumption after optimization against those from results before optimization is illustrated. From the optimal results, it can be seen that the total operation cost after optimization is only 81.5% as before in winter, the effect is significant. Although the structure of subsea pipelines is different from onshore pipelines, the hydraulic and thermodynamic calculation methods are the same, and the optimal operation method can be used for both onshore and subsea pipelines.

Pipeline: The Worst Transportation Method of Oil, Except for All the Rest

This paper studies the safety and environmental impacts of different crude oil transportation methods. The frequency, spillage volume, and environmental damage costs of pipeline accidents seem to be significantly higher than of trains and trucks. However, after adjusting for the distance and volume of oil transported by each method, pipeline has the lowest number of accidents, the least amount of oil discharged and the smallest environmental damage and clean-up cost per ton-mile. Moreover, lacking oil transmission pipeline hinders the producer's ability to collect associated gas. Consequently, the gas is flared or vented. The Granger causality between the excess takeaway capacity of oil pipeline and natural gas flaring confirms the impact of having inadequate transmission pipeline capacity.