Oil Gathering Pipeline Research Articles

Testing the functionality of OLGA software for determining optimal oil transport modes to prevent solid particle deposition

Background: During operation, all mechanical impurities entering the collector through the flow lines settle at the bottom due to a decrease in flow velocity. This leads to a reduction in the capacity of the pipeline network, increased pressure, and premature equipment wear. To address this issue it is essential to understand the dynamics and intensity of sludge formation at the bottom of the pipeline. Aim: Evaluate the functionality and efficiency of the dynamic multiphase flow simulator in addressing challenges related to the transport of borehole fluid containing solid particles. Materials and methods: To build a mathematical simulation of multiphase flow with solid particles using OLGA specialised software, we selected one of the oil gathering lines in field N, with a diameter of 159х10 mm and a length of 1600 m, as the study object. This oil gathering line collects production from 16 wells. The OLGA simulator was used to model the process and measure flow parameters with different particle diameters, predicting the dynamics of variables such as time-varying flow velocities, fluid composition, temperatures, and particulate deposition. For a flow with a particle diameter of 104 µm, active precipitation occurs at flow rates between 200 and 300 m³/day. At flow rates of 400 m³/day and above, the velocity is sufficient to carry the particles without significant accumulation in the pipeline. Results: The software enabled the calculation of the dynamic system for different solid particle diameters in multiphase flow, addressing the challenge of evaluating the dynamics of solid phase accumulation in the pipeline and determining the fluid flow velocity required to prevent sludge formation. The software is suitable for implementing simulation modelling to develop technical solutions that minimise the risks of solid particle deposition in oil gathering pipelines during the operation of on-shore infrastructure facilities. Conclusion: The software enabled the calculation of the dynamic system for different solid particle diameters in multiphase flow, addressing the challenge of evaluating the dynamics of solid phase accumulation in the pipeline and determining the fluid flow velocity required to prevent sludge formation. The software is suitable for implementing simulation modelling to develop technical solutions that minimise the risks of solid particle deposition in oil gathering pipelines during the operation of on-shore infrastructure facilities.

Internal Corrosion Control Strategy of Oil Gathering and Transportation Pipeline

Abstract Internal corrosion and perforation of metal pipelines is the main reason for failure of gathering and transportation pipelines in a western oil field. The content of Cl-in the transport medium of the oilfield is between 24910-118051mg/l, the total salinity is between 65404-39363mg/l, the reduced sulfur content is between 6-36mg/l, and the number of SRBS is between 20-300 /ml, which are the main factors leading to corrosion in the pipeline. Through investigation, demonstration and field test, the internal corrosion control technology system of pipeline has been formed, which includes internal extrusion coating, internal penetration, 32MPa high pressure flexible composite pipe, polyethylene lined FRP composite pipe technology. The internal corrosion control strategy has been popularized in oil field, and the effect is good.

Simulation of melting characteristics of thermal washing of the wax layer in the pipeline based on lattice Boltzmann method

ABSTRACT The escalation of transportation costs and the obstruction of pipelines due to wax deposition significantly impact the secure and efficient production of oil fields. The thermal washing method, characterized by its simplicity and cost-effectiveness, is widely employed for dewaxing crude oil gathering pipelines. The investigation of the melting mechanism of the wax layer during thermal washing is extremely important. In this paper, the two-zone composite model of multiphase flow-porous medium in the mushy zone is introduced into the solid-liquid phase change lattice Boltzmann model based on the enthalpy method, and the problem of circumferential inhomogeneity in the melting of the wax layer and the important influence of flow and heat transfer in the mushy zone on the thermal washing are systematically investigated. The demarcation point (γ tr) between the high and low liquid fraction zones is measured to be 0.81 by microscopic experiment. The impacts of varying γ tr and Ste numbers on wax melting at different circumferential locations are analyzed in detail. The results show that the melting efficiency of wax exhibits a nonlinear enhancement from − 90° to 90°. The melting efficiency of wax decreases with increasing γ tr for wax layers between 90° and − 45°. The melting efficiency of wax increases with higher Ste numbers at all angles. The Ste number increases from 0.42 to 5.0, and the melting efficiency of the wax layer at angles ranging from 90° to − 90° increases by factors of 2.16, 2.16, 2.20, 2.61, and 3.33 respectively. The growth of the Ste number improves the warming rate and shortens the generation time of convection at the center point of the wax layer. The research findings serve as a fundamental reference for formulating a rational and efficient thermal washing scheme.

Application of simulation to optimize the oil-gathering system of the “N” oil field

Background: In the period of 20122021 456 wells were drilled in the western, northern and central sections of the N oil field. The construction of additional wells in the coastal zone (western part) will increase the volume of liquid entering the Group Metering Plant (GMP) -A, which is already operating above designed capacity. Given the above, it was decided to build a new GMP-P on the western section.
 Aim: The purpose of this work was the need to determine the optimal option for placing the designed GMP-P.
 Materials and methods: A hydraulic calculation of the Oil Production Shops oil gathering system (OPS) of the N field was carried out by simulating a multi-phase steady flow in a specialized software package with conversion using a geographic information system for reference to the terrain.
 Results: For the first time, the OPS-1 oil gathering pipeline system of the N field was completely digitized. In the course of the work, 4 options for optimizing the OPS-1 gathering system with different locations for the construction of the GMP-P were considered.
 Conclusion: Based on the results of the study, option 2 of the GMP-P construction location was selected and justified.

Factors Influencing the CO2 Corrosion Pattern of Oil–Water Mixed Transmission Pipeline during High Water Content Period

After the oil field enters the high water content period, the oil–water mixed fluid in the mixing system will gradually change into the water-in-oil mixed fluid, while the dissolved CO2 causes the pH value of the mixed fluid to decrease. There is also a certain amount of bacteria in the output fluid, with many factors leading to the intensification in the corrosion of the oil–water mixed system pipeline in the high water content period. To clarify its corrosion law, through the mixed transmission pipeline material, 20# carbon steel, in high water conditions under the action of different single factor dynamic corrosion rate experiments, along with the use of the SPSS method, were used to determine the corrosion of the main control factors. The results show that in the high water content period, the corrosion rate of the mixed pipeline 20# steel gradually increases with the increase in temperature pressure, CO2 partial pressure, SRB content, Ca2+ + Mg2+ content, and Cl− content. The corrosion rate with the CO2 partial pressure and SRB content changes show a strong multiplicative power relationship; with Ca2+ + Mg2+ content, Cl− content changes show a logarithmic relationship, the relationship degree R2 is above 0.98. Through SPSS data analysis software combined with experimental data for correlation degree analysis, it is concluded that the correlation magnitude relationship between each factor and corrosion rate is CO2 partial pressure > SRB content > Cl− content > Ca2+ + Mg2+ content > temperature pressure, which provides a theoretical basis for the corrosion protection of an oil gathering pipeline.

Experimental and molecular dynamics simulation investigations of adhesion in heavy oil/water/pipeline wall systems during cold transportation

With the increased water content in heavy oil gathering pipelines and application of cold transportation methods, understanding adhesion behavior in heavy oil/water/pipeline wall systems has greatly gained in importance. Here, a combined experimental and molecular dynamics (MD) simulation was used to investigate the effect of the heavy oil composition and molecular structures on adhesion. The capacity of heavy oil adhesion and the effect of adding asphaltene molecules to the heavy oil were studied experimentally. MD simulation systems with different asphaltene concentrations were established based on the NPT and NVT ensembles. The results showed that the addition of asphaltene increases the adhesion of heavy oil by as much as 16.60–83.35%. The center of mass, mean square displacement, and radial distribution function of heavy oil droplets were also analyzed, which indicated that the viscosity and thickness of the heavy oil adhesion layer were also affected by the asphaltene content. The functional groups in asphaltene molecules promote the adhesion of oil droplets and inhibit the adhesion of the water phase. Further, asphaltene aggregates are formed by face-to-face stacking, which severely impedes heavy oil flow assurance. The results from this study greatly contribute to understanding the mechanisms of heavy oil adhesion during cold transportation.

Corrosion mechanism and anticorrosion technology of oil and gas gathering and transportation pipeline

In the process of oilfield exploitation, the composition of crude oil is relatively complex, which may have strong corrosive medium, and the oil field gathering and transportation pipeline is distributed in various areas of the oilfield, which plays an important role. The corrosive medium of crude oil has a certain corrosive effect on the oil field gathering and transportation pipeline, and once the corrosion is serious, it will cause the leakage of the gathering and transportation pipeline. China’s oilfields have experienced many years of continuous development, some oilfields have entered the middle and late stage of exploitation, and have made certain achievements in various stages of exploitation. We have conducted in-depth research and Analysis on the corrosion factors of oil gathering and transportation pipeline, which consumes a lot of manpower, material resources and financial resources. Therefore, we need to analyze and study the factors influencing the corrosion of oil gathering and transportation pipeline, formulate effective anti-corrosion measures according to the actual situation, extend the service life of oil gathering and transportation pipeline, and promote the longterm development of oil field exploitation and operation.

Local corrosion: calculation in oil field conditions (according to weight measurements)

Complications associated with a corrosive environment, according to Rosneft’s data at 01.01.2020, are among the prevailing at oil and gas production facilities and rank fourth among other factors complicating production – 12% the complicated mechanized wells. Failures due to corrosion are the second largest complicating factors. Based on the results of approbation, the article proposes a method for calculating the maximum rate of local carbon dioxide corrosion, applicable in oilfield conditions, including to complicated stocks of oil wells and pipelines of oil gathering systems. Based on the approbation results, a method for calculating the maximum rate of local carbon dioxide corrosion, applicable in oilfield conditions, including to complicated stocks of oil wells and oil-gathering pipelines systems is proposed in the article. The proposed technique is realizable according to the results one of «traditional» methods the corrosion monitoring - weight (or gravimetric). The approbation results and application possibility of the technique in the pilot tests process in assessing the protective ability of corrosion inhibitors and the selection of the effective dosages in relation to local damages, which are the main cause the oilfield equipment failures according the factor «Corrosive aggressiveness» (one of the complicating factors in terms of gradation, adopted in the Rosneft Company regulations). On practical examples the oilfield equipment operation, the results of corrosion monitoring and the summary statistics the corrosive stock of wells (using the example of an oil Company), the current situation with respect to this type of complication and relevance the issue under consideration is shown.

Effect of velocity and water cut on water distribution in elbows of petroleum pipelines

As one of the main energy sources, petroleum and natural gas are widely used around the world. Safety of the transportation causes more attentions recently. Currently, since some oil wells are in the late period of the production, water pre-injection is often used to rise the well pressure. Thus, the water cut is usually high in oil gathering pipelines. The inner wall of pipelines without coating would be corroded by contacting with the mixed corrosive medium and water during the long-term running, which may even lead to leakage accidents. Researches about flow pattern of oil-water multiphase flow pipes are mainly about straight pipelines, but few about elbows. In this work, water distributions in elbows of gathering pipelines were studied according to the experimental results and computational fluid dynamics (CFD) simulation results. The water deposited when the fluid velocity was low enough and the water cut is high. According to the simulation results and experimental results, an oil-water phase inversion curve was obtained to be guidance for water distribution analysis in elbows.

Numerical study for removing wax deposition by thermal washing for the waxy crude oil gathering pipeline.

Exploring the wax removal process by numerical simulation is beneficial for guiding field operations. In this paper, enthalpy-porosity and volume of fluid (VOF) methods were adopted to simulate the melting process of wax in the crude oil gathering pipeline. The melting patterns and liquid fraction of the wax were used to validate the mathematical model. The results show that the wax melts quickly before the liquid fraction reaches 80%, while the remaining 20% melts very slowly. Since the water with higher density sinks to the lower part of the pipeline, the wax in the lower part of the pipeline melts first, while the wax in the upper part of the pipeline melts slowly. The water temperature and flow rate disproportionately affect the melting process. Increasing the water temperature and flow rate can accelerate the melting process, but the effects on shortening the melting time of wax gradually decrease. Increasing the flow rate, the heat transfer rate and the melting rate are increasing progressively, the change of flow rate also affects the outlet temperature of the pipeline.

Test Analysis of Corrosion Perforation in a Crude Oil Gathering Pipeline

The reason for perforation leakage of gathering pipeline in an oilfield was investigated by size measurement, mechanical properties, metallographic structure, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrum (EDS). The results showed that the failure form of the spirally submerged arc welded pipe (SAW) was the corrosion perforation caused by local corrosion. The main cause of corrosion perforation was due to the existence of chlorine ion, H2O and O2 in the pipeline transportation medium. A large cathode and small anode electrode corrosion formed in the pipe marking area and the base metal, which eventually led to the perforation of the steel pipe.

Research on a Safety Assessment Method for Leakage in a Heavy Oil Gathering Pipeline

At present, the number of oil and gas gathering and transportation pipelines is numerous, and leakage accidents occur frequently. Each year, due to pipeline failure, there are immeasurable consequences for people and the environment around the affected pipelines. In order to reduce the risk of leakage accidents in heavy oil gathering pipelines and prevent the occurrence of major spills, it is of great significance to carry out safety assessments of them. However, failure data of these pipelines is seriously deficient and statistical methods used to evaluate pipeline safety are incompatible. Therefore, this paper proposes a risk assessment system for heavy oil gathering pipelines in the absence of failure data. Firstly, a Bayesian network (BN) for the leak safety evaluation of heavy oil gathering pipelines is established via mapping from a bow-tie (BT) model. Then, information diffusion theory is combined with fuzzy set theory to obtain the failure probability of each factor affecting the pipeline failure, and then the failure probability of the pipeline is obtained by the full probability formula. In addition, in order to assess the extent of consequences due to accidents, variable fuzzy set theory is used to comprehensively consider the consequences of the leakage of heavy oil gathering pipelines. Finally, the above two parts are combined to form a safety assessment system to realize risk management and control for pipelines, which is necessary to ensure the safety of heavy oil gathering pipelines.

A mathematical model of the pulsator for cleaning paraffin deposits of pipelines and downhole equipment

An important task for the oil industry is considered the issue of cleaning paraffin deposits of downhole and surface equipment; Xmas tree, oil gathering pipelines, oil treatment plants. As a result of the paraffin blockage, there is a decrease in oil production, an increase in pressure drop in pipelines, disruption of the normal operation of oil collection and treatment devices, the field operation itself is still difficult, therefore preventing and removing paraffin deposits with various cleaning methods is a pressing problem in the oil industry.

To the issue of the destruction of persistent oil emulsions in order to ensure high-quality oil treatment

The article raises a question about the qualitative preparation of separator oil under the conditions of the formation of stable emulsion, which is stabilized by the products of the production of hydraulic fracturing and acid treatments. We present relations that make it possible to determine the flow parameters of produced gas-liquid mixture in an oil gathering pipeline. As a result, we propose a technological scheme for oil treatment, which provides the required quality of oil treatment. The scheme is based on the developed and justified method of dynamic combined oil treatment.

QUANTITATIVE DIAGNOSTICS METHODS FOR ASPHALT-RESIN-PARAFFIN DEPOSITS IN WELLS AND OIL PIPELINES

Background The formation of asphalt-resin-paraffin deposits in oil-producing wells and oil collectors depends largely on the temperature and pressure conditions for transporting the gas-liquid mixture; therefore, monitoring the temperature and pressure at oil producing facilities along the entire length of the facilities becomes relevant. The appearance of organic deposits in the well leads to a change in the speed of movement of the well production, retains its thermal energy, increases the pressure in the pipes. The equilibrium in the «reservoir - well - pump» system changes due to the increase in pressure at the discharge of the submersible electric centrifugal pump. Temperature sensors, installed evenly along the length of the lifting pipe string, provide important information on the temperature distribution in the pipe string without deposits and with deposits. Thermometry during the well operation will show the effect of fluctuations in the dynamic level of the fluid on the formation of sediments, will increase the informational content of measures for the inhibition and removal of sediments from wells. Aims and Objectives: to justify different methods of using pressure and temperature sensors in wells and oil gathering pipelines for evaluating their internal state; show the possibility of thermometry on a stationary basis for the implementation of a quantitative diagnosis of deposits in the tubing string of an oil producing well. Methods The known dependences of the state of the gas-liquid mixture on the thermobaric conditions in the tubing string of the well pipes and the continuity equation of the pipeline products are used. Results A method has been developed to monitor the formation of asphalt-resin-paraffin deposits in a tubing string according to temperature sensors, which are uniformly distributed along the length of the tubing on a stationary basis.

INVESTIGATION OF PETROLEUM PIPELINES EMERGENCY

The Russian Federation is one of the leaders in the extraction, transporta- tion and refining of oil. A significant part of the hydrocarbon raw materi- als is concentrated in the northern regions of the country, where the cli- matic conditions of production are severe, besides the situation is aggra- vated by the complicating conditions due to the presence of various aggressive impurities causing the internal corrosion of pipeline systems. The targets include maintaining production at the level of 500 million tons per year until 2020 and increasing gas production from 600 billion cubic meters per year to 1 trillion cubic meters per year in the short term to 2040. Implementation of the mentioned plans will require the use of innovative technology solutions from the oil and gas industry, the use of new mate- rials with improved hydraulic characteristics and increased resource. At the same time, the tasks of maintaining and improving the operational reliability of pipelines and oilfield equipment in the fields in general are coming to the fore. The solution of such tasks should be made taking into account the requirements in the field of industrial and economic security. The technical strategy of oil and gas companies in terms of occupational health and industrial safety is aimed at preventing emergency and fire and explosion hazard situations, for this purpose the tasks of ensuring continuous monitoring of the technical condition of production facilities are systematically solved. The article is devoted to the analysis of the current situation regarding the accident rate of oil gathering pipeline systems. The work provides recommendations for improving the performance of existing oil-gather- ing pipeline systems through the use of preventive measures to reduce the process of streaking corrosion of the internal surface of pipelines.

Treatment on oil/water gel deposition behavior in non-heating gathering and transporting process with polymer flooding wells

Against a background of crude oil shortage and low-carbon economy, optimization and simplification of oil–gas gathering and transporting play an indispensable role in efficient development of oilfield. Profit from the high efficient utilization of the produced liquid self-energy, single-pipe non-heating gathering and transporting process has been recognized in polymer flooding wells of Daqing oilfield (China). However, it is also facing the challenges of deposition, partial blockage, high wellhead pressure, production fluctuation and environment management. A field investigation of the application for the non-heating process and the variation of polymer flooding wellhead pressure were recently carried out. The flow patterns of the oil, water and gas mixture in single-pipe process were identified, and the locations where the gel deposition was most likely to occur were estimated. Deposition inhibitions and removal processes were practiced, and the operation parameters under different working conditions were optimized. The results indicated that single-pipe non-heating process could reduce 20% of the investment and 30% of the running cost and could also make the wellhead pressure of some wells exceed the maximum allowable operating pressure of oil gathering pipelines. There appears to be a proportional relationship among water content, flow rate, residual polymer concentration and gel deposition behavior in a certain range of gathering radius. The gel deposition rate of the produced liquid with polymer concentration of higher than 600 mg/L and the water content of 90.5% reached 0.1154 mm/h in the coldest climate under the normal flow rate of 85 t/d, and the theoretical pigging period was <10 days. Gelation nucleation which was related to emulsification was induced by the transition and coexistence of separated flow and dispersed flow in non-heating gathering pipelines. The main deposition located on the beginning of pipelines, manifold, valve and elbow, and wellhead pressure of 350 psi was created in the test period of 20 days. Although using chemical inhibition method could still obtain a drag reduction rate of more than 25% under crude oil gelation temperature, the fact of the centralization disability of wellhead dosing facilities and the potential threat of chemical inhibitors to the environment could not be ignored. The noticeable energy consumption and potential risks of pipeline restarting may be encountered using facilities improvement and sphere pigging operation in gel deposition behavior treatment. A relation schema which could be used to predict deposition rate and extract thermal flush period according to the actual working condition was established. The successful application of the non-heating gathering and transporting process combated the traditional view that heat tracing is essential for maintaining the surface process in extremely cold area. Furthermore, the results contributed to the existing literature in establishing subsurface and surface parts integration idea for a green field development and accelerate further application of non-heating gathering and transporting process.

Modelling the effects of production rates and physico-chemical parameters on pitting rate and pit depth growth of onshore oil and gas pipelines

To estimate the pitting rate of internally corroded oil and gas gathering pipelines, a multivariate regression modelling was carried out, using pitting rates and operating parameters. These operating parameters, temperature, pH, CO2 partial pressure, water cut, wall shear stress, chloride ion concentration, sulphate ion concentration, operating pressure, oil production rate, gas production rate and water production rate, were obtained from routine monitoring of the pipelines, whereas, the pitting rates (mean pit depths over time) were determined by the ultrasonic thickness measurement technique. The operating parameters and pitting rates were also used to estimate the pit depth growth of the pipelines using Monte Carlo simulation, and field data were used to test the developed models. The results obtained indicated that the pipelines under severe pitting corrosion rate were, more conservatively predicted than those under low, moderate and high pitting corrosion rates.

Computer Simulation of Stress-Strain State of Oil Gathering Pipeline Designed for Ugut Field

The paper presents the stress and strain state modeling of infield pipeline in Ugut oil field. The finite element models of the stress field distribution in the pipeline wall are presented in this paper. The attention is paid to the pipeline reliability under stress conditions induced by the internal pressure and external compressive or tensile loads.

ИССЛЕДОВАНИЕ ВНУТРЕННЕЙ ПОВЕРХНОСТИ ТРУБОПРОВОДА СИСТЕМЫ НЕФТЕСБОРА СЕВЕРО-КРАСНОЯРСКОГО МЕСТОРОЖДЕНИЯ

Background It is known that the presence in oil of a non-polar phase is an important factor of corrosion in heterogeneous media. Hydrocarbon phase, almost inert to metal at low temperatures, accumulates hydrogen sulfide in higher amounts, in comparison with the aqueous phase. This increases the potential aggressiveness of a heterogeneous system as a whole, and promotes diffusion of aggressive agents and maintenance of their high concentrations at the «metal - electrolyte» interface. This results in the intensive processes of electrochemical destruction and hydrogenation of the metal. Aims and Objectives To identify the causes of metal destruction along the lower generatrix of the internal surface of oil gathering pipeline in the Northern Krasnoyarsk field. To determine the corrosion rate of the base metal and metal in the bottom of the pit by plottig polarization curves. Methods Laboratory electrochemical corrosion tests were carried out using a held-down cell. Values of potential, corrosion current density and corrosion rate were measured using potentiostat. We used the three-electrode electrochemical system in which a sample cut from the pipeline spool was the working electrode and the platinum and silver chloride reference electrodes were supporting ones. Nitrogen purging of the medium was carried out. Polarization curves were recorded in potentiodynamic mode after two hours of the working electrode exposure to corrosive environment. The rate of corrosion was measured by means of potentiostat in compliance with the method of linear polarization resistance. Results Obtained polarization curves showed that the corrosion rate of base metal was 0.11 mm/year, and the rate of corrosion at the bottom of the pit was 3.45 mm/year. The authors suggest that the accelerated pitting of equipment could be caused by that the corrosion inhibitor could not get to the metal surface due to deposition of the heavy fraction of liquid hydrocarbons at low flow rates. Pilot tests demonstrated that the cleaning of pipelines from deposits and corrosion products, and subsequent inhibition resulted in a significant reduction of the pitting corrosion.