Field Pipeline Research Articles

DEVELOPMENT OF LEAK DETECTION METHODS FOR USE IN FIELD PIPELINE TRANSPORT

Today, most existing leak detection methods are effective only for stationary operating conditions of pipelines. During transient (dynamic) pumping modes, a significant decrease in the sensitivity of the methods occurs, or inoperability of leak detection systems (LDS) based on them is observed.Accordingly, for the operation of the LDS in the presence of transient processes in pipelines, it is necessary to use special approaches that take into account the features and interrelation of the monitored indicators of the dynamically changing pumping regime with each other. One solution to this problem is the use of a dynamic thermal-hydraulic model of the pipeline, which makes it possible to calculate pumping indicators at intermediate and boundary points of the pipeline at each moment in time.The article presents the developed digital model of a pipeline transporting single-phase flows, as a system of equations obtained from the laws of conservation of mass, momentum and energy. The model describes all significant processes and effects during the movement of the pumped flow through a pipeline and allows you to calculate the main characteristics of the flow, including finding the pressure and temperature distributions along the pipeline route.The method for detecting leaks from field pipelines operating under transient (dynamic) conditions is to compare the actual measured flow rate at the end point of the pipeline with the flow rate calculated using a dynamic model of this pipeline, into which the measured pumping indicators at the inlet of a real object are previously transferred. If there are significant deviations between the calculated pumping flow rate at the outlet of the pipeline in the model and the flow rate measured at the pipeline, a leak is concluded.In order to check the performance of the proposed solutions, modeling of leaking pipelines was carried out in specialized software at various flow rates, media viscosities and leak volumes. Based on the data obtained, a conclusion was made about the efficiency of the developed method.Thus, thanks to the proposed approach, it will be possible to promptly detect and eliminate leaks and withdrawals through unauthorized taps on field pipelines operating in unsteady mode, which in turn will significantly reduce operating costs associated with eliminating the consequences of failures.

Study on the Destruction Law and Main Controlling Factors of Corrosion Product Film in H2S-CO2 Coexistence System

Abstract The failure law and main controlling factors of corrosion product film in this corrosion environment were studied according to the characteristics of H2S-CO2 coexistence in a gas field pipeline, so as to provide guidance for corrosion prevention and control of gas field pipeline. Sediment effects of sand particles in the pipeline on corrosion, the influence of flow rate, dissolved oxygen and sediment on corrosion products were analyzed by conducting corrosion experiments at 0.5m/s, 1m/s and 2m/s, corrosion experiments without oxygen and aerobic conditions. The destruction law of corrosion product film in pipeline and the main controlling factors of corrosion product film in single well pipeline and gathering and transportation line were determined. The results show that high flow rate will cause local damage of corrosion product film and promote pitting corrosion, dissolved oxygen will destroy the integrity of corrosion product film, and sediment is one of the factors causing local corrosion and perforation of pipeline inner wall. The corrosion product film structure of the gas field pipeline will be destroyed and pitting corrosion under the condition of high flow rate, oxygen and sand deposition. Meanwhile, the main control factor affecting the corrosion product film destruction of the gas field single well pipeline is dissolved oxygen, and the main control factor affecting the corrosion product film destruction of the gas field gathering and transportation main line is sediment.

Simulation of Elbow Erosion of Gas–Liquid–Solid Three-Phase Shale Gas Gathering Pipeline Based on CFD-DEM

Shale gas gathering pipelines often contain liquid water and solid sand in the early stage of production, which leads to the failure of pipeline components easily under the action of gas–liquid–solid three phases. A computational fluid dynamics (CFD) model based on the fluid volume method (VOF) and discrete element method (DEM) was established to study the flow law of gas–liquid–solid three-phase flow in the elbow of shale gas gathering pipeline and the erosion law of the inner surface of the elbow was studied by coupling the Oka erosion prediction model. By comparing the experimental results of erosion damage of the elbow, it is found that the model established can well predict the erosion characteristics and erosion amount under the action of three phases. Combined with the field pipeline parameters and operating conditions, the paper further simulates the elbow erosion behavior under relevant working conditions. The results show that the particles rotate clockwise from the outer wall of the pipe through the bottom of the pipe when passing through the elbow under the action of gas and water phases. When the gas velocity increases, the particles at the elbow mainly gather at the bottom of the elbow and the wall of the outer arch. When the water content increases gradually, the particles gathered on the outer arch wall of the elbow move along the outer arch wall of the elbow and face the inner arch surface gradually, and the erosion area is mainly concentrated on the outer arch wall of the elbow and the outlet horizontal pipe. Under the condition of the liquid phase, the movement characteristics of the water phase and particles in the elbow of the gas gathering pipeline and the erosion characteristics of the pipeline surface are obviously different from those under the condition of the gas–solid two-phase. The model and simulation results established in this paper provide a reference for the erosion damage protection of shale gas gathering pipeline elbow.

ON THE PERFECTION OF THE APPROACH TO THE FORMATION OF A PROGRAM FOR INCREASING THE RELIABILITY OF FIELD PIPELINES IN OC ROSNEFT

The article describes an approach for ranking and selecting field pipelines based on the total cost of ownership of the facility for the purpose of timely repairs and minimization of accidents, as well as its software implementation. The principle of the proposed approach is to apply a technical and economic model of the total cost of ownership of a pipeline, which takes into account the costs of maintaining the pipeline over a long period of time, which include the costs of pipeline maintenance activities, pipeline failures and replacement of pipeline sections. This model allows determining which replacement year corresponds to the minimum accumulated maintenance costs, by varying the year of pipeline replacement from the start of operations to the planning horizon. The model also allows to take into account the impact of operational technological measures on the cost of pipeline ownership and the selection of the optimal year of repair.In order to take into account the level of pipeline accidents in the process of operation on the basis of operational data, a mathematical probabilistic model based on the Weibull distribution was developed. The mathematical model allows to take into account for each pipeline the influence of technical characteristics (diameter, length, wall thickness, material, coating, design features), operating conditions (type of pumped medium, technological mode of pipeline operation) and information on inspection and diagnostics. The accuracy of failure prediction using this model is at least 90 %.The approach to the formation of programs to improve the reliability of field pipelines with regard to optimal repair periods based on the total cost of ownership model is described, taking into account various objectives and constraints, among which the main ones are:- required achievable level of accidents;- acceptable amounts of financing for re-pairs;- permissible physical volumes of repairs along the length.The approach to forming reliability improvement programs described in this article has been implemented in Rosneft's corporate software system RN-SM. The implementation of this software package in production activities is being implemented in 2023–2024.

Gas pipeline leakage detection and location by using w-FBG array based micro-strain sensing technology

In addressing the significant security concerns associated with urban natural gas transportation, particularly the potential catastrophic consequences of leaks, this paper introduces a novel approach for detecting and locating leaks in natural gas pipelines using weak fiber Bragg grating (w-FBG) array micro-strain sensing technology. The field pipeline model is established, w-FBG array is applied to pipeline leakage experiment, and the pipeline leakage is detected by analyzing the change trend of micro-strain. The pipeline leakage experiments under different pressures were carried out. The experimental results show that there is a good linear relationship between the pipeline leakage pressure and the wavelength change of w-FBG, and the linearity is greater than 0.99, which is consistent with the theoretical analysis and verifies the applicability of w-FBG. According to the characteristics of micro-strain transfer in pipeline leakage process, a ‘abrupt change point’ capturing method based on peak to peak slope and threshold judgment is proposed. Results indicate that the proposed algorithm effectively detects pipeline leaks and accurately locates the point of leakage, with a positioning error of approximately 0.5 m. Compared with the traditional method, the proposed method has higher precision.

Research Progress of Failure Mode Diagnosis Methods for Oil and Gas Field Pipelines

In recent years, the service safety evaluation of oil and gas pipelines in the whole life cycle has attracted the attention of many researchers. This paper summarizes the failure modes of oil and gas pipelines and focuses on four machine learning-based oil and gas pipeline failure mode diagnosis methods: fault tree analysis method, failure expert system evaluation method, the fuzzy comprehensive evaluation method of pipeline failure, failure mode, and impact analysis method, and prospects the development of oil and gas pipeline failure mode diagnosis technology, in order to provide a reference for subsequent research.

Hydromechanical vibrator-pulsator for restoring the injectivity of injection wells

The article presents a bench model of a vibrator pulsator with a hydromechanical principle of operation designed for processing the bottom-hole zone of the reservoir of injection and production wells, columns of tubing, field pipelines.The design uses a spring-loaded rotary valve. The design of the test bench is described. According to the results of bench tests, the parameters of the pulsator’s stable operation were revealed: at a liquid flow rate of 0.012 m3/s, the oscillation amplitude of the pulsator body was 300 microns, the amplitude of liquid pressure fluctuations was 1.8 MPa at a frequency of 8 Hz. The results of field tests for cleaning columns of pumping and compressor pipes, field pipelines of oil collection are presented.

Determination of deflections of above-ground pipelines under loads in the longitudinal and transverse directions

The most common method of construction of field pipelines in permafrost-dominated areas is above-ground laying on supports. The size of the span between bearings is determined taking into account the condition of tuning out resonance frequencies in case of vortex excitation due to wind load. For these purposes it is necessary to determine the natural frequencies of vibrations of above-ground pipeline sections. When determining the natural frequencies of pipeline sections, it is necessary to take into account the initial position caused by additional loads in longitudinal and transverse directions (pre-stressed state of pipeline sections). A differential equation for determining the position of a pipeline section under stationary loads in longitudinal and transverse directions based on the rod theory is obtained. The numerical solution of the equation is obtained using the finite difference method. The influence of longitudinal and lateral forces is evaluated. It is shown that the influence of longitudinal and lateral loads has a significant effect on the initial position of pipeline sections. Therefore, the complex influence of loads should be taken into account for the correct determination of deflections. The initial position of the pipeline under the action of various combinations of loads can be used to evaluate the preliminary stress-strain state in the design of above-ground pipelines.

Experimental study on wax deposition of highly paraffinic oil in intermittent gas-oil flow in pipelines

Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines. This paper investigated the two main aspects of oil-gas two phase wax deposition layer: apparent thickness and crystal structure characteristics. A typical highly paraffinic oil in Bohai Sea, China, was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures, superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental device. Just as in the classical theory of wax molecular diffusion, it showed that wax deposition thickness of oil-gas two phase increased with increasing oil temperature. Analysis of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit thickness. In addition, the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering (SAXS) for different circumferential positions, flow rates and gas-oil ratios. The bottom deposition layer had a complex crystal structure and high hardness, which were subject to change over flow rate variations. Furthermore, the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main mechanism. Our study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process occurs. Our findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oil-gas two phase that occurs easily in multiphase field pipelines.

APPROACH TO THE SELECTION OF TYPES OF POLYMER-COMPOSITE PIPES FOR FIELD PIPELINES

The work is devoted to the use of polymer-composite pipes (PCP) in the field conditions of the oil and gas industry. Based on a review of existing types of non-metallic pipes of various designs used for the construction of field pipelines, a knowledge base of current technological solutions has been formed and their advantages and disadvantages have been identified. A catalog of technological solutions for field pipelines has been developed, which includes a description of the designs of PCP with their technical characteristics necessary for the design and operation of field pipelines. An applicability matrix has been developed that allows one to determine suitable types and designs of PCP according to technical principles for pipeline construction under certain conditions. The selection criteria are pipe sizes, operating parameters (pressure and temperature), service life, pumped media, purpose of the pipeline and resistance to aggressive media (CO2, H2S). If the PCP meets the specified conditions, this product is included in the matrix for further use in the construction and operation of the pipeline. However, in order to be able to equip fields with pipelines made of polymer-composite materials, it is necessary that solutions made from PCP are not only technically sound, but also economically justified in comparison with steel pipes. One of the main results of this study is the development of a feasibility study methodology (FS) of applicability, which allows us to determine the most effective option for the design and operation of pipelines made of PCP based on a comparison of economic indicators. The methodology was based on a comparison of the cost of steel and polymer-composite products, the cost of construction and installation work and the speed of their implementation, the cost of maintaining pipelines during operation, as well as the costs associated with pipe failures - to eliminate their consequences.
 As part of the study, the accident rate of steel and polymer-composite pipes was also analyzed and studied, on the basis of which a methodology for predicting accident rates for PCP was created.
 Finally, conclusions are made about the possibility of using the developed tools in the oil and gas industry.

КОМПЛЕКСНАЯ МОДЕРНИЗАЦИЯ ЭЛЕКТРОПРИВОДА ПРИ ОРГАНИЗАЦИИ РЕМОНТНЫХ РАБОТ ТРУБОПРОВОДНЫХ СИСТЕМКОМПЛЕКСНАЯ МОДЕРНИЗАЦИЯ ЭЛЕКТРОПРИВОДА ПРИ ОРГАНИЗАЦИИ РЕМОНТНЫХ РАБОТ ТРУБОПРОВОДНЫХ СИСТЕМ

The issues of organizing repair work on field pipeline systems during the production of liquid hydrocarbons are considered. The influence of the quality of washing of contaminated parts on repair operations was determined. Measures have been proposed to improve the efficiency of jet washing machines. To expand the functionality, it is proposed to introduce into the design an adjustable electric drive for rotating the washing basket. This will allow you to optimize the rota-tion speed in relation to the specifics of the part and the level of contamination

Scaling two-phase gas-liquid flow in horizontal pipes

Two-phase flow in pipelines is analyzed by experimental facilities and also numerical analysis. The experimental facilities are designed by scale-down field pipelines. Therefore, the accuracy of experimental data is strongly dependent on the scaling method. In this research, an approach for downscaling field pipelines into experimental facilities is proposed. The fluid flows in different scales for various flow patterns including Stratified, Stratified Wavy, Slug, Plug and Bubbly are numerically simulated and validated against full-scale experimental data. The results of the scaled-down model simulation are in excellent agreement with the full-scale facilities, affirming the robustness of the downscaling method. This research enhances the understanding of scaled-down experiments for various flow conditions.

Modeling of the dynamics of the movement of hydrate formation inhibitors in an extensional pipeline

The dynamics of the movement of the hydrate formation inhibitors (methanol and monoethylene glycol) in an extensional hilly terrain field pipeline transporting a multiphase fluid is studied. The concentration distribution of inhibitors along the pipeline length is obtained by means of the hydrodynamic modeling using OLGA software for a wide range of the gas flow rates. The influence of liquid accumulation on the time of the pipeline filling by an inhibitor is analyzed. It is shown that the time of the inhibitor propagation through the pipeline is governed by the average velocity of the aqueous phase. It is demonstrated that the time of the pipeline filling by methanol can be significantly less than that by monoethylene glycol. It is shown that after the required equilibrium concentration of the inhibitor is reached along the entire length of the pipeline, the pressure drop in the liquid accumulation mode is less when methanol is used. The results obtained can be used to optimize the methods of the inhibition of extensional hilly terrain field pipelines. Keywords: hilly terrain pipeline; hydrodynamic modeling; multiphase flow; liquid accumulation; hydrate inhibitor.

Application of Fluid Mechanics in Flow Meter Principle Analysis and Process Simulation

COMSOL is used to establish a flow field pipeline model, design and optimize flow detection, and analyze and study acoustic intensity, pressure signal and other parameters. According to the circular pipe test system used in the experiment, the flow velocity analysis model of the steady and constant flow field in the circular pipe was theoretically constructed using the finite element method. The numerical analysis results show that the flow rate in the pipeline obtained in the experiment is the average flow rate of the fluid at the section of the test location, and the test value is 0.63% different from the theoretical value.

Analysis of safety factors in the calculation of strength by internal pressure of oil and gas field and main pipeline systems

The article is devoted to the analysis of the safety factors used in the calculations for the internal pressure strength of oil and gas pipelines. A number of national, regional and international normative technical documents regulating the design of pipelines were considered. The safety factors provided in these documents in the calculation of the strength of pipelines are analyzed. For a comparative estimation, mathematical models were developed. As a result of the analyzes, the use of a safety factors for the yield strength of pipe material was recognized as more acceptable in calculating the strength of pipelines. The authors give recommendations on the choice of safety factors depending on the mode of operation and the type of transported hydrocarbon products. AzDTN2.2-9 is the only regulatory document in force in the territory of the Republic of Azerbaijan in this sphere. As this document does not meet modern criteria and is morally outdated, it was considered expedient to develop a new regulatory and technical act taking into account the suggestions made.

TECHNOLOGIES FOR THE DEPOSITS VOLUME ASSESSING USING REFERENCE LIQUIDS IN PIPELINES

The gas-liquid mixture flow along an oil and gas field pipeline is a complex process, the parameters of which, as a rule, are not determined along its length. Pressure and temperature of water-oil emulsion decrease along the pipeline length, pressure and temperature conditions of separation from oil both light components in the form of associated petroleum gas and heavy components – in the form of asphaltenes, resins, paraffins and mechanical impurities – change. Two techniques for deposit quantitative diagnostics in the pipeline are discussed in the article. Viscosity and velocity of injected reference fluid in the pipeline section complicated by deposits are considered as informative parameters when using pressure sensors and ultrasonic flowmeter.
 Technologies for the quantitative assessment of deposits in oilfield pipelines based on the control of the movement of a fluid with a reference property different from the property of the pipeline fluid are proposed. According to the first technology, the viscosity of the liquid is changed and the pressure difference at the beginning and at the end of the pipeline with deposits is fixed in time. According to the second technology, the value of the increased velocity of fluid movement in places where the pipeline is narrowed due to the presence of deposits is measured. The theoretical basis of the processes occurring with liquids in pipeline transport is substantiated. With an increase in the viscosity of the reference liquid, the degree of compression of the liquid increases and, as a result, the frequency of vibrations of the liquid molecules increases. With a decrease in the viscosity of the reference liquid, the reverse picture is observed.

THE USE OF ULTRASOUND TOMOGRAPHY TO IMPROVE ULTRASOUND CONTROL EFFICIENCY

To ensure safe and reliable operation of pipeline systems, it is necessary to regularly carry out work on technical diagnostics. Ultrasonic inspection is one of the most common methods for pipeline technical condition determining. It has many advantages over other control methods among which there can be distinguished accessibility, the absence of additional requirements for equipping the object under examination, the absence of an impact on the object of control itself, and safety. But ultrasonic inspection also has disadvantages some of which can be eliminated by using an individual piezo elements of multi-element transducer instead of simple single-element transducers.
 The method of pipeline wall thickness determining using piezo elements of a multi-element transducer, as well as searching for and identifying the type and size of the defect, is known as ultrasonic tomography.
 This paper presents the main features of the transducers used in ultrasonic tomography, possibilities of ultrasonic tomography when it is used in field pipeline diagnostics. The advantages of using the method of ultrasonic tomography in comparison with conventional ultrasonic control are considered.

Prediction of yield stress of waxy gels in pipelines using scaling theory and crystallization kinetics

The development of a novel coupled kinetic and rheological model for paraffinic wax oil gelation is presented. The crystallization kinetics was studied by differential scanning calorimetry, and the rheological properties were obtained by dynamic oscillatory tests. The mass fraction of the crystallized wax, critical elastic strain, storage modulus in the Hookean region, and yield stress were obtained for model oils with 2.5, 5.0, and 7.5 wt% wax at cooling rates of 0.5, 0.75, and 1.0 °C/min. By applying such cooling range to the waxy oils, it was possible to verify the effect of this variable on fractal dimensional analysis using well-known scaling models for the first time. The scaling models used were successfully applied to conciliate the new gathered data enabling the discussion of their microstructural characteristics. From the kinetic and rheological behavior observed, simulations of waxy oil gelation during a pipeline shutdown were also performed. The yield stress evolution was estimated from zero to 14 days of quiescent cooling. With the aid of this novel methodology, the pressure needed to restart the flow and the time for maintenance services without pipeline blockage could be estimated based on the radial yield stress profile, providing a more accurate measurement than the direct extrapolation of yield stress measurements for field pipelines.

An analysis of the influence of the technological mode of the gathering system of the oil field on the efficiency of geological and technical actions

Field development at a late stage is characterized by high water-cut and considerable volumes of produced water that causes field pipeline congestion. An increase in the volume of produced water entails an increase in hydraulic resistance in pipeline sections, which may limit the effect of ongoing geological and technical actions to intensify oil production. As a result, the production rates decrease at neighboring wells, but at the same time, the hydraulic resistance in the sections of overloaded pipelines increases. In this regard, it makes sense to determine the boundary, which allows you to observe the balance between the increase in amount of geological and technical actions and the current field pipeline congestion.

Sourcing high tissue quality brains from deceased wild primates with known socio‐ecology

Abstract The selection pressures that drove dramatic encephalisation processes through the mammal lineage remain elusive, as does knowledge of brain structure reorganisation through this process. In particular, considerable structural brain changes are present across the primate lineage, culminating in the complex human brain that allows for unique behaviours such as language and sophisticated tool use. To understand this evolution, a diverse sample set of humans' closest relatives with varying socio‐ecologies is needed. However, current brain banks predominantly curate brains from primates that died in zoological gardens. We try to address this gap by establishing a field pipeline mitigating the challenges associated with brain extractions of wild primates in their natural habitat. The success of our approach is demonstrated by our ability to acquire a novel brain sample of deceased primates with highly variable socio‐ecological exposure and a particular focus on wild chimpanzees. Methods in acquiring brain tissue from wild settings are comprehensively explained, highlighting the feasibility of conducting brain extraction procedures under strict biosafety measures by trained veterinarians in field sites. Brains are assessed at a fine‐structural level via high‐resolution MRI and state‐of‐the‐art histology. Analyses confirm that excellent tissue quality of primate brains sourced in the field can be achieved with a comparable tissue quality of brains acquired from zoo‐living primates. Our field methods are noninvasive, here defined as not harming living animals, and may be applied to other mammal systems than primates. In sum, the field protocol and methodological pipeline validated here pose a major advance for assessing the influence of socio‐ecology on medium to large mammal brains, at both macro‐ and microstructural levels as well as aiding with the functional annotation of brain regions and neuronal pathways via specific behaviour assessments.