scholarly journals Research into phase transformations in reservoir systems models in the presence of thermodynamic hydrate formation inhibitors of high concentration

2021 ◽  
Vol 230 ◽  
pp. 01014
Author(s):  
Nazar Pedchenko ◽  
Ivan Zezekalo ◽  
Larysa Pedchenko ◽  
Mykhailo Pedchenko
Keyword(s):  
Phase Transformations ◽  
Gas Hydrate ◽  
Oil And Gas ◽  
Solid Phase ◽  
Three Dimensional ◽  
Hydrate Formation ◽  
Oil And Gas Industry ◽  
Difficult Problem ◽  
High Concentration ◽  
Gas Hydrate Formation

Gas hydrates have been and still remain a difficult problem in the oil and gas industry, solution of which requires considerable efforts and resources. In this work, the mechanism of phase transformations at negative temperatures in the formation of the solid phase is preliminarily studied using the reservoir system models consisting of a gas mixture and a solution of gas hydrate formation inhibitor of thermodynamic action with high concentration in distilled water. A system of three-dimensional lighting and image magnification is used to visually detect phase boundaries by creating optical effects. Thus, in the system “inhibitor solution – gas hydrate – gas” in the process of gas hydrate recrystallization in the conditions close to equilibrium, microzones of supercooled water may occur, which in the absence of gas molecules access is crystallized into ice. The result of such solid phase structure formation is its increased stability in nonequilibrium conditions for a relatively long period of time.

New «green» inhibitors of gas hydrate formation for the oil and gas industry based on polysaccharides

2021 ◽  
pp. 33-40
Author(s):  
V.A. Dokichev ◽  
◽  
A.I. Voloshin ◽  
N.E. Nifantiev ◽  
M.P. Egorov ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Oil And Gas ◽  
Hydrate Formation ◽  
Field Tests ◽  
Oil And Gas Industry ◽  
Quasi Equilibrium ◽  
Green Inhibitor ◽  
Gas Industry ◽  
Gas Hydrate Formation ◽  
Thermobaric Conditions

The thermobaric conditions for the formation of gas hydrates in the presence of the sodium salt of carboxymethylcellulose, dextran, and arabinogalactan were studied in a quasi-equilibrium thermodynamic experiment. It is established that polysaccharides slow down the rate and change the conditions of gas hydrate formation of a mixture of natural gases, showing the properties of a thermodynamic and kinetic inhibitor with technological efficiency exceeding methanol by 170-270 times when used in the same dosages. The results of the development of a «green» synergistic inhibitor of gas hydrate formation «Glycan RU» on their basis are presented, which includes a combination of thermodynamic and kinetic inhibitors. Pilot field tests of «Glycan RU» were carried out at the wells of the Priobskoye, Prirazlomnoye, Ombinsky, Zapadno-Ugutskoye oilfields. It was found that at dosages of 1000 g/m3 and 500 g/m3, there is no formation of hydrate plugs in the annulus. «Glycan RU» is recommended for industrial use by the technology of periodic injection and/or continuous dosing through wellhead dispensers. Keywords: carboxymethylcellulose; dextran; arabinogalactan; polysaccharides; «green» inhibitor of gas hydrate formation; «Glycan RU».

scholarly journals A Quick-Look Model to Predict Gas Hydrate Formation in Gas Pipelines using Modified Navier-Stokes Correlation

2020 ◽  
pp. 1-11
Author(s):  
Akinsete O. Oluwatoyin ◽  
Oladipo O. Olatunji ◽  
Isehunwa O. Sunday
Keyword(s):  
Gas Hydrate ◽  
Oil And Gas ◽  
Hydrate Formation ◽  
Oil And Gas Industry ◽  
Navier Stokes ◽  
Fluid Composition ◽  
Gas Pipelines ◽  
Navier Stokes Equation ◽  
Gas Industry ◽  
Gas Hydrate Formation

Major challenges associated with the smooth production operations in the oil and gas industry that has raised technical curiosity are formation of natural gas hydrates in production facilities and flow lines which introduces significant cost to operators. Accurate modeling is therefore paramount; most existing models are based on constitutive conservation laws neglecting other dissipative energy types. To predict “if” and “where” gas hydrate would be formed in gas pipeline, the Navier-Stokes equation was modified by incorporating dissipative forces of viscosity and gravity; the equation that emerged was solved analytically to determine the hydrate formation pressure (HFP) and the position of hydrate formation along gas pipelines. The developed model, used as a quick-look tool for where and if hydrates will form revealed that when the predicted HFP is positive hydrates was formed but when it is negative hydrates were not formed. The model also showed that HFP is a function fluid composition, mass flowrate, changes in fluid and surrounding conditions and changes in elevation and direction confirming the results of earlier work done.

Investigation of the performance of low-dosage hydrate inhibitors combined with wax inhibitors for a mixed CH4-CO2 gas hydrate formation

2015 ◽  
Vol 93 (9) ◽  
pp. 992-997
Author(s):  
Xuemei Lang ◽  
Pingping Lv ◽  
Shurui Xu ◽  
Baoyao Li ◽  
Shuanshi Fan ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Induction Time ◽  
Negative Impact ◽  
Hydrate Formation ◽  
Oil And Gas Industry ◽  
Growth Time ◽  
High Concentration ◽  
Oil Pipeline ◽  
Gas Hydrate Formation ◽  
Low Dosage

Within the oil and gas industry, low-dosage hydrate inhibitors (LDHIs) are a proven technology to control hydrates. Besides hydrate inhibitors, wax inhibitors (WIs) are frequently injected to prevent wax buildup in the crude oil pipeline. However, little attention has been focused on the effect of wax inhibitors on the performance of LDHIs. In this study, performance tests of 3 LDHIs in the presence of wax inhibitors were carried out for a 67% CH4/33% CO2 gas hydrate formation. Using the isothermal cooling method at pressures of 9 MPa and temperatures of 4 °C (subcooling is 9 °C), the results showed that the induction time of CH4-CO2 gas hydrate formation with LDHI/WI was shorter than the system with only LDHI. During the growth period, when the concentration of the WIs was 1 mass%, the growth time of the system with LDHI/WI was prolonged. Taking the induction time and the growth time into consideration, it was found that WIs had a more negative impact on the kinetic hydrate inhibitor performance at low dosage. The effect of WIs at high concentration could be negligible.

Investigation of Drilling Problems in Gas Hydrate Formations

2008 ◽  
Author(s):  
Catalin Teodoriu ◽  
Gioia Falcone ◽  
Amodu Afolabi
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Hydrate Formation ◽  
Oil And Gas Industry ◽  
Lessons Learned ◽  
Drilling Fluids ◽  
Drilling Mud ◽  
Gas Hydrate Formation

Gas hydrates are ice-like crystalline systems made of water and methane that are stable under high pressure and low temperature conditions. Gas hydrates have been identified as strategic resources and may surpass all known oil and gas reserves combined. However, these resources will become reserves only if the gas contained therein can be produced economically. In the oil and gas industry, gas hydrates may be encountered while drilling sediments of the subsea continental slopes and in the subsurface of permafrost regions. They also represent a flow assurance issue, as they may form in the well and in the flowlines, causing blockages. Deepwater drilling programmes have experienced problems when encountering gas hydrate formations. A major issue is that of phase transition, where gas hydrate goes from a solid state to dissociated gas and water, as there are rapid changes in fluid volumes and pressure. This can cause drilling equipment failure, borehole instability and formation collapse. After dissociation of water and gas, hydrates may be prevented from forming in the well by using appropriate inhibitors in the drilling mud. There is a need to develop fluids specifically for drilling through gas hydrate formations, either to unlock the unconventional reserves trapped in the crystalline gas hydrate structures or to safely reach underlying conventional reserves. To drill wells in a gas hydrate formation, a conductor casing is needed to allow close loop circulation of the mud, if different from seawater. The search for the ideal mud for drilling through gas hydrate formations must start with a review of past experiences worldwide and of the lessons learned. This paper presents a review of the problems encountered while drilling through gas hydrate formations. It identifies the key requirements for drilling fluids, based on the interaction between the drill bit, the drilling fluid and the formation. An evaluation of the environmental risk associated with drilling through gas hydrate formations is also presented.

Coupled Heat and Mass Transfer CFD Model for Methane Hydrate

2015 ◽  
Author(s):  
Eugenio Turco Neto ◽  
M. A. Rahman ◽  
Syed Imtiaz ◽  
Thiago dos Santos Pereira ◽  
Fernanda Soares de Sousa
Keyword(s):  
Natural Gas ◽  
Multiphase Flow ◽  
Gas Hydrate ◽  
Gas Flow ◽  
Three Dimensional ◽  
Hydrate Formation ◽  
Cfd Model ◽  
Flow Metering ◽  
Ansys Cfx ◽  
Gas Hydrate Formation

The gas hydrates problem has been growing in offshore deep water condition where due to low temperature and high pressure hydrate formation becomes more favorable. Several studies have been done to predict the influence of gas hydrate formation in natural gas flow pipeline. However, the effects of multiphase hydrodynamic properties on hydrate formation are missing in these studies. The use of CFD to simulate gas hydrate formation can overcome this gap. In this study a computational fluid dynamics (CFD) model has been developed for mass, heat and momentum transfer for better understanding natural gas hydrate formation and its migration into the pipelines using ANSYS CFX-14. The problem considered in this study is a three-dimensional multiphase-flow model based on Simon Lo (2003) study, which considered the oil-dominant flow in a pipeline with hydrate formation around water droplets dispersed into the oil phase. The results obtained in this study will be useful in designing a multiphase flow metering and a pump to overcome the pressure drop caused by hydrate formation in multiphase petroleum production.

scholarly journals Performance of Waterborne Polyurethanes in Inhibition of Gas Hydrate Formation and Corrosion: Influence of Hydrophobic Fragments

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5664
Author(s):  
Roman S. Pavelyev ◽  
Yulia F. Zaripova ◽  
Vladimir V. Yarkovoi ◽  
Svetlana S. Vinogradova ◽  
Sherzod Razhabov ◽  
...  
Keyword(s):  
Corrosion Inhibitor ◽  
Oil And Gas ◽  
Hydrate Formation ◽  
Oxygen Demand ◽  
Oil And Gas Industry ◽  
Dual Function ◽  
Structure Property ◽  
Tert Butyl ◽  
Waterborne Polyurethanes ◽  
Gas Hydrate Formation

The design of new dual-function inhibitors simultaneously preventing hydrate formation and corrosion is a relevant issue for the oil and gas industry. The structure-property relationship for a promising class of hybrid inhibitors based on waterborne polyurethanes (WPU) was studied in this work. Variation of diethanolamines differing in the size and branching of N-substituents (methyl, n-butyl, and tert-butyl), as well as the amount of these groups, allowed the structure of polymer molecules to be preset during their synthesis. To assess the hydrate and corrosion inhibition efficiency of developed reagents pressurized rocking cells, electrochemistry and weight-loss techniques were used. A distinct effect of these variables altering the hydrophobicity of obtained compounds on their target properties was revealed. Polymers with increased content of diethanolamine fragments with n- or tert-butyl as N-substituent (WPU-6 and WPU-7, respectively) worked as dual-function inhibitors, showing nearly the same efficiency as commercial ones at low concentration (0.25 wt%), with the branched one (tert-butyl; WPU-7) turning out to be more effective as a corrosion inhibitor. Commercial kinetic hydrate inhibitor Luvicap 55 W and corrosion inhibitor Armohib CI-28 were taken as reference samples. Preliminary study reveals that WPU-6 and WPU-7 polyurethanes as well as Luvicap 55 W are all poorly biodegradable compounds; BODt/CODcr (ratio of Biochemical oxygen demand and Chemical oxygen demand) value is 0.234 and 0.294 for WPU-6 and WPU-7, respectively, compared to 0.251 for commercial kinetic hydrate inhibitor Luvicap 55 W. Since the obtained polyurethanes have a bifunctional effect and operate at low enough concentrations, their employment is expected to reduce both operating costs and environmental impact.

CO2-saturated Salinity Environment Effects on Ni-Mo Alloys at Gas Hydrate Formation Temperatures

2019 ◽  
Author(s):  
Christopher Ozigagu ◽  
Ting Zhou ◽  
Stephen Sanders ◽  
Teresa Golden
Keyword(s):  
Corrosion Resistance ◽  
Deep Water ◽  
Gas Hydrate ◽  
Surface Characterization ◽  
Oil And Gas ◽  
High Salinity ◽  
Hydrate Formation ◽  
Test Solution ◽  
Low Salinity ◽  
Gas Hydrate Formation

Corrosion and gas hydrate formation are flow assurance problems that can cause serious safety problems in deep water environments. One aspect that has been given less attention is the corrosion behavior of materials in salinity environment where gas hydrate formation and CO2 (sweet) corrosion can both occur. This type of environment is common in oil and gas deep water environments. The aim of this work is to investigate the effects of CO2-saturated salinity environment on Ni-Mo alloys at gas hydrate formation temperatures using electrochemical, SEM/EDX, and XRD surface characterization techniques. The immersion test solutions were sweet low-salinity (CO2 + 1 wt% salt + 5 oC) and sweet high- salinity (CO2 + ~24 wt% salt + 5 oC) environments, respectively. The as-deposited Ni-Mo alloy coating has the highest corrosion resistance of 33.28 kΩ cm2. The corrosion resistance dropped to 14.36 kΩ cm2 and 11.11 kΩ cm2 after 20 hrs of immersion in the sweet low-salinity and sweet high-salinity test solutions respectively. From grazing incidence XRD, the (111) reflection peak of the Ni-Mo coating was depressed and broaden after immersion in both test solutions due to increase in oxide layer formation on the surface of the Ni-Mo coating. SEM revealed a cracked surface morphology after immersion in sweet high-salinity test solution and elemental analysis shows the presence of oxygen after immersion in both test solutions. The oxygen content increased from 1.70 wt% after immersion in sweet low-salinity test solution to 2.37 wt% after immersion in sweet high-salinity test solution.

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