Ground Pipelines Research Articles

Identification and Analysis of Corrosion Mechanisms for Ground Pipelines with Hanging Rings

Recently, corrosion perforation has been frequently seen in surface pipelines in the oil and gas industry, resulting in operational and environmental challenges. Due to the complex characteristics and mechanisms of such corrosion, a new and pragmatic method has been designed to identify and evaluate the corrosion phenomenon via a hanging ring installed in a surface pipeline. In addition to respectively analyzing the ions of water samples with chemical titration, ion chromatography, and mass spectrometry, the micro-surface morphology of the corroded hanging rings was observed and evaluated by using a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), and the surface composition of the corroded hanging rings was analyzed by using X-ray diffraction (XRD). The water ions of each selected position were found to mainly contain Ca2+, Ba2+, SO42−, and HCO3−, while the barium scale and calcium carbonate scale were formed in situ. In addition to the common corrosion induced by CO2, corrosion induced by both CO2 and H2S leads to extremely serious corrosion and scaling in surface pipelines. In addition, the injection dose of corrosion inhibitor was also evaluated.

Research on Straightness Perception Compensation Model of FBG Scraper Conveyor Based on Rotation Error Angle.

The accurate perception of straightness of a scraper conveyor is important for the construction of intelligent working faces in coal mines. In this paper, we propose a precision compensation model based on rotation error angle to improve the accuracy of the fiber Bragg grating (FBG) curvature sensor of a scraper conveyor. The correctness of the model is verified by theoretical analysis, numerical simulation, and experiments. Finally, the feasibility of the model is analyzed and discussed for field application in a coal mine. When the rotation error angle is within the range of 0~90°, according to the strain of FBG obtained by numerical simulation, the radius of the curvature is inversely calculated by the compensation model. The relative error of each discrete point is within ±0.9%, and the relative error after fitting is less than 0.2%. The experiment shows that the relative error of the curvature radius after fitting according to the theoretical formula is less than ±3%, and the relative error of the curvature radius value obtained by the inverse deduction of each discrete point is less than ±6%, which verifies the correctness and applicability of the compensation model. In addition, the compensation model with the FBG curvature sensor has broad application prospects in coal mine underground conveyors, submarine pipelines and ground pipelines.

Structural optimization of disperser in polymer flooding distribution tank based on venturi pulse injection

ABSTRACT Polymer was carried by liquid in conventional polymer dispensing tank of polymer flooding in oilfield. Polymer particles often gather in the process of polymer blending, resulting in blockage of ground pipelines and formation. To reduce this phenomenon, finite element method was used. Optimization of polymer tank carrier based on venturi tube gas pulse injection. The polymer particles were carried into the liquid distribution tank by the injection method of pulse airflow to realize efficient carrying. Study on the effect of different pulse intensity and pulse waveform on cohesion. The results showed that the combined effect of strong pulse difference and pulse gap could make the airflow have strong carrying capacity for difficultly migrated polymer particles. Optimized the shortest pulse time and got the shortest time of triangle wave, sawtooth wave, square wave, and sine wave under simulated conditions. Time was 5.1 s, 6.3 s, 6.2 s, 6.2 s, respectively. The corresponding pulse frequencies were 20 times/s, 15 times/s, 10 times/s and 30 times/s, respectively. Properly increasing pulse intensity could enhance the carrying capacity of pulse airflow to polymer and reduced the carrying time of polymer. The optimal pulse parameters were triangular wave with pulse intensity of about 120 m/s and pulsed frequency of 20 times/s. Established the phenomenon and reason of indoor experiment. The viscosity of polymer solution after stirring was higher than that of liquid flow carried by gas phase pulse. This shows that the polymer system was more fully dissolved under the condition of gas phase pulse carrying. Pulsed airflow injection could effectively reduce polymer aggregation and shear action of agitator to protect polymer structure. Pulse airflow injection also plays an important role in safe operation of ground pipelines and stable seepage in porous media.

Mathematical model of propagation of liquid vibrations in a tubing string

Effectiveness of wave processes in tubing strings, wells and long pipelines may be limited by damping of hydrodynamic waves along the length of the channel. Violation of thermodynamic equilibrium in reservoir fluids during their rise to the surface and in ground pipelines may be accompanied by the release of asphalt-resin-paraffin components in the flow of crystals due to a decrease in temperature and pressure. Subsequent depositing of crystals takes place as they grow, due to adhesion to the wall of pipes, the surface of equipment. Deposits are most intensified in areas of local expansion and narrowing of the cross-section area of the flow (occurrence of vortices).

Pipelining Appalachia: A perspective on the everyday lived experiences of rural communities at the frontline of energy distribution networks development

The transport of natural gas through transmission and distribution networks spans 2.4 million miles of underground and above ground pipelines in the USA. This Perspective uses a critical energy justice framework to analyze Appalachian's everyday lived experiences at the frontline of energy distribution network development. The practice of installing pipelines, as well as the sheer magnitude of the pipeline system, has transformed small rural communities into industrial sites. This Perspective also adds to the emerging concept of energy justice by bringing to the forefront Appalachian residents’ voices in relation to burgeoning pipeline constructions, which are often missing from the debate on energy independence. Energy justice is based on the principle that people should not only have safe and affordable energy, but they should be protected from disproportionate negative impacts associated with generating and transmitting energy as well. Our findings are that those who reside near pipelines express fear of explosions, leaks, and negative health outcomes and are disproportionately impacted. In addition, they are concerned about regulation, state responsibility, and threats of eminent domain. We highlight how these communities are socially affected, and how residents’ daily lives are altered in inequitable ways by the construction of energy distribution networks.

A numerical study on the non-isothermal flow characteristics of superheated steam in ground pipelines and vertical wellbores

Traditional heavy oil recovery method of saturated steam injection faces many challenges. Present study on wellbore modeling of superheated steam (SHS) flow is still at the early stage.In order to fill this gap, a series of works were conducted to study the non-isothermal flow characteristics of SHS in ground pipelines and vertical wellbores. Firstly, a flow model inside the wellbores was proposed based on the energy and momentum balance equations. Then, coupled with heat transfer model in formation or atmosphere, a comprehensive model was developed. Then, type curves of SHS flow in ground pipelines and vertical wellbores were obtained by solving the model with finite difference method. Finally, model validation and sensitivity analysis were conducted.The results show that: (a). there exist a good agreement between predicted results and field data. (b). superheat degree increases with increasing of injection rate. (c). superheat degree increases with increasing of injection temperature. (d). superheat degree decreases with increasing of injection pressure. Consequently, practicing engineers are suggested to increase the injection rate and temperature and to decrease the injection pressure.

Modelling brittle fracture propagation in gas and dense-phase CO2 transportation pipelines

The development and application of a fluid–structure interaction model for simulating the transition of a through-wall defect in pressurised dense (150bar, 283.15K) and gas phase (34bar, 283.15K) CO2 pipelines into a running brittle fracture is presented. Given the economic incentives, the fracture model is employed to test the suitability of the existing stock of natural gas pipelines with the relatively high ductile to brittle transition temperatures of 0 and −10°C for transporting CO2 in the terms of their resistance to brittle fracture propagation. The hypothetical but nevertheless realistic scenarios simulated involve both buried and above ground 10km long, 0.6m i.d. pipelines. Based on the assumption of no blowout of the surrounding soil upon the formation of the initial leak, the results show that the transition of the leak into a running brittle fracture in buried CO2 pipelines is far more likely as compared to above ground pipelines. In addition, gas phase pipelines are more prone to undergoing a propagating brittle fracture as compared to dense phase pipelines despite the lower operating pressures of the former. Furthermore, counter-intuitively, isolation of the feed flow following the discovery of a leak is shown to facilitate brittle fracture failure. The initial defect geometry on the other hand is shown to have a profound impact on the pipeline's resistance to propagating brittle fractures.

Ultrasonic isolation of buried pipes

Long-range guided wave testing (GWT) is used routinely for the monitoring and detection of corrosion defects in above ground pipelines. The GWT test range in buried, coated pipelines is greatly reduced compared to above ground configurations due to energy leakage into the embedding soil. In this paper, the effect of pipe coatings on the guided wave attenuation is investigated with the aim of increasing test ranges for buried pipelines. The attenuation of the T(0,1) and L(0,2) guided wave modes is measured using a full-scale experimental apparatus in a fusion-bonded epoxy (FBE)-coated 8in. pipe, buried in loose and compacted sand. Tests are performed over a frequency range typically used in GWT of 10–35kHz and compared with model predictions. It is shown that the application of a low impedance coating between the FBE layer and the sand effectively decouples the influence of the sand on the ultrasound leakage from the buried pipe. Ultrasonic isolation of a buried pipe is demonstrated by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both the pipe and sand, and has the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is found to be substantially reduced, in the range of 0.3–1.2dBm−1 for loose and compacted sand conditions, compared to measured attenuation of 1.7–4.7dBm−1 in the buried FBE-coated pipe without the PE-foam. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry and incorporated into model predictions of guided wave propagation in buried coated pipe. Good agreement is found between the experimental measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges; such coatings would be attractive for new pipeline installations.

Choosing a Reclamation Seed Mix to Maintain Rangelands During Energy Development in the Bakken: A proper revegetation seed mix keeps land in livestock production and minimizes weed invasions

On the Ground Pipelines across the eastern Montana–western North Dakota portion of the northern Great Plains are proliferating due to continuing oil and gas development. Pipelines are linear disturbances reclaimed after construction, and they impact a large number of livestock producers. While livestock are usually removed from pastures during the construction phase, proper reclamation and revegetation paired with informed grazing management may return pastures to use quickly and profitably. Research is needed to determine how the simultaneous seeding of an annual cover crop with desired perennial grasses can enhance livestock production while ensuring the success of perennial grass forage species.

An Experimental Study on Anti-Corrosion Coating of Ground Oil and Gas Equipment

This common ground for today's oil and gas equipment corrosion paint, accelerated through the neutral salt spray corrosion test, Indoor UV / Condensation accelerated weathering test, Water permeability test and Resistance to chloride ion permeability test on the ground pipelines and oil and gas equipment commonly used Preservative fluorocarbon paint, silicone and acrylic polyurethane coating research laboratory tests carried out by these kinds of High-performance anti-corrosion paint used for comparison, the three coatings have good weather resistance, Fluorocarbon coating seepage rate lower than the other two coatings, anti-UV aging better than the other two coating, Fluorocarbon coating chloride ion penetration lower than the acrylic polyurethane coating.