scholarly journals Study on microscopic growth mechanism of emulsion system hydrate

2020 ◽  
Vol 37 (3) ◽  
pp. 71-77
Author(s):  
Jin Zhang ◽  
An Chen ◽  
Menglan Duan
Keyword(s):  
Growth Mechanism ◽  
Hydrate Formation ◽  
Emulsion System ◽  
Water Droplets ◽  
Natural Gas Hydrate ◽  
Flow Loop ◽  
Hydrate Shell ◽  
Physical Information ◽  
Series Of Experiments ◽  
Hydrate Formation Process

In order to master the microscopic growth mechanism of natural gas hydrate, a series of experiments were carried out using a high-pressure hydrate flow loop. The microscopic physical information of the growth of hydrates in the emulsion system is captured by advanced microscopic equipment and the phenomena of the experiments show that: 1) not all water droplets instantaneously generate a hydrate shell, but only a few of the water droplets gradually generate a hydrate shell when reaching the conditions of the hydrate formation; and 2) the coalescence and shear do occur in the hydrate formation process, and the distribution of hydrate particle size has changed.

scholarly journals Study on the growth rate of natural gas hydrate in water-in-oil emulsion system using a high-pressure flow loop

RSC Advances ◽  
2018 ◽  
Vol 8 (64) ◽  
pp. 36484-36492 ◽  
Author(s):  
Xiaofang Lv ◽  
Bohui Shi ◽  
Shidong Zhou ◽  
Haoping Peng ◽  
Yun Lei ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Pressure ◽  
Focal Point ◽  
Emulsion System ◽  
Natural Gas Hydrate ◽  
Flow Loop ◽  
Oil Emulsion ◽  
Water Pipelines ◽  
Slurry Transport ◽  
Water In Oil Emulsion

Hydrate slurry transport technology in deep-water pipelines has become a focal point among worldwide researches, due to its high economic efficiency.

Experimental Study on Blockage of Gas Hydrate Slurry in a Flow Loop

2012 ◽  
Author(s):  
Xiaofang Lv ◽  
Da Yu ◽  
Wenqing Li ◽  
Bohui Shi ◽  
Jing Gong
Keyword(s):  
Influencing Factor ◽  
Hydrate Formation ◽  
Diesel Oil ◽  
Flow Loop ◽  
Relative Time ◽  
Key Points ◽  
Oil And Natural Gas ◽  
Multi Phase Flow ◽  
Series Of Experiments ◽  
Multi Phase

Hydrate formation and blockage in long deepwater pipelines has long been a trouble for offshore petroleum production. Consequently, understandings of the procedures as well as influencing factors of hydrate blockage are key points to make reasonable flow assurance strategies. Thus two series of experiments have been conducted in a high-pressure hydrate flow loop newly constructed by multi-phase flow research group in China University of Petroleum (Beijing). One of the systems consists of water and CO2, while the other one includes water, diesel oil and natural gas. The relative time of hydrate blockage has been studied by varying pressure and flow rate for both two systems. The dimensions of hydrate particles in fluid during plugging are also investigated. The results indicate that the influencing factor exerts a similar effect on the relative time for the different systems. Besides, the sizes of particles in the fluid would change significantly due to hydrate formation.

Evaluation on the natural gas hydrate formation process

2020 ◽  
Vol 28 (3) ◽  
pp. 881-888 ◽  
Author(s):  
Shuqi Fang ◽  
Xinyue Zhang ◽  
Jingyi Zhang ◽  
Chun Chang ◽  
Pan Li ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Hydrate ◽  
Formation Process ◽  
Hydrate Formation ◽  
Natural Gas Hydrate ◽  
Gas Hydrate Formation ◽  
Hydrate Formation Process

Natural gas hydrate formation dynamics in a diesel water-in-oil emulsion system

2018 ◽  
Vol 36 (20) ◽  
pp. 1649-1656 ◽  
Author(s):  
Zhen Pan ◽  
Zhe Wang ◽  
Zhien Zhang ◽  
Guiyang Ma ◽  
Li Zhang ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Emulsion System ◽  
Natural Gas Hydrate ◽  
Oil Emulsion ◽  
Gas Hydrate Formation ◽  
Formation Dynamics ◽  
Water In Oil Emulsion

scholarly journals Influence of the water level in the work area on the hydrate formation process

2018 ◽  
Vol 194 ◽  
pp. 01038
Author(s):  
Anton V. Meleshkin ◽  
Dmitriy S. Elistratov
Keyword(s):  
Water Level ◽  
Formation Process ◽  
New Technologies ◽  
Hydrate Formation ◽  
High Rate ◽  
Condensation Process ◽  
Work Area ◽  
Series Of Experiments ◽  
Working Section ◽  
Hydrate Formation Process

This article describes a fundamentally new method for obtaining gas hydrates, based on self-organization in a closed working section of the cyclic boiling-condensation process of the gas-hydrate generator. A special feature of this method is the high rate of hydrate formation at low energy costs and, as a consequence, the expected efficiency of new technologies built on its basis over analogues. A series of experiments was performed, which shows the effect of the water level on the work site on the hydrate formation process.

Experimental Study on Natural-Gas-Hydrate-Slurry Flow

SPE Journal ◽  
2013 ◽  
Vol 19 (02) ◽  
pp. 206-214 ◽  
Author(s):  
X.F.. F. Lv ◽  
J.. Gong ◽  
W.Q.. Q. Li ◽  
B.H.. H. Shi ◽  
D.. Yu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Length Distribution ◽  
Hydrate Formation ◽  
Diesel Oil ◽  
Slurry Flow ◽  
Flow Loop ◽  
Reflectance Measurement ◽  
System Pressure ◽  
Series Of Experiments ◽  
Water Cut

Summary To better understand hydrate-slurry flow, a series of experiments was performed, including water, natural gas, and diesel oil, under 4-MPa system pressure and 1.25-m/s initial linear velocity. The experiments have been conducted in a high-pressure hydrate-flow loop newly constructed at China University of Petroleum (Beijing), and dedicated to flow-assurance studies. A focused-beam reflectance measurement (FBRM) probe is installed in this flow loop, which provides a qualitative chord length distribution (CLD) of the particles/droplets in the system. First, the influence of flow rate on the hydrate-slurry flow was discussed. Then, we studied other influencing factors—such as water cut and additive dosage—on the hydrate induction period and the CLD before/after hydrate formation. Third, a new correlation was fitted between the dimensionless rheological index n′ and water cut as well as additive dosage, according to these experimental data. Finally, a laminar-flow model for the prediction of the pressure drop for the quasisingle-phase hydrate slurry was established, and tested by comparison with the experimental results in this paper.

Hydrate-Bedding Mechanisms in Partially Dispersed Water/Oil Systems

SPE Journal ◽  
2019 ◽  
Vol 25 (02) ◽  
pp. 0925-0937 ◽  
Author(s):  
Vishal Srivastava ◽  
Ahmad A. A. Majid ◽  
Pramod Warrier ◽  
Giovanny Grasso ◽  
Carolyn A. Koh ◽  
...  
Keyword(s):  
Crude Oil ◽  
Droplet Size ◽  
Hydrate Formation ◽  
Water Volume ◽  
Water Droplets ◽  
Flow Loop ◽  
Inversion Point ◽  
Pressure Drops ◽  
Dispersed Systems ◽  
Transient Operations

Summary Gas hydrates are considered a major flow-assurance challenge in subsea flowlines. They agglomerate rapidly and form hydrate blockages. During transient operations [shut-in and restart (RS)], risk of blockage formation owing to hydrates can be greater compared to that during the continuous operations. In particular, hydrate formation during an unplanned shut-in and subsequent restart could lead to increased operational hazards. In this work, flow-loop tests were conducted under both continuous-pumping (CP) and RS conditions, using Conroe crude oil with three different water fractions (30, 50, 90 vol%) at 5 wt% salinity, over a range of mixture velocities (from 2.4 to 9.4 ft/sec). It was determined that RS operations resulted in an earlier onset of hydrate particle bedding—twice as fast as those in CP tests—from the interpretation of pressure-drop and mass-flow-rate (MFR) measurements. Droplet imaging using a particle vision and measurement (PVM) probe suggested larger water droplets (100–300 µm) during the shut-in, as compared to the CP tests (=40 µm) at 50 and 90 vol% water cuts (WCs). For the tests performed using a demulsifier at 200 ppm, PVM images suggested larger water droplets (mean droplet size = 94 µm), as compared with the test with no demulsifier (mean droplet size = 21 µm). The test using a demulsifier resulted in higher pressure drops and lower MFRs compared with the test with no demulsifier, indicating poor hydrate transportability when water was partially dispersed in the oil phase. The current study indicated that partially dispersed systems present greater risks of hydrate plugging as compared with the fully dispersed systems in the range of water volume fractions from 50 to 95 vol% WC, which was the phase inversion point of the water-in-crude-oil (Conroe14 crude) system. The flow-loop-test analyses presented in this work can potentially aid in an improved mechanistic understanding of RS operations, involving unplanned shut-ins and restarts.

Mathematical model of multiphase flow propagation for the case of underwater pipeline damage

2019 ◽  
Vol 14 (2) ◽  
pp. 142-147
Author(s):  
S.R. Kildibaeva ◽  
E.T. Dalinskij ◽  
G.R. Kildibaeva
Keyword(s):  
Oil And Gas ◽  
Control Volume ◽  
Hydrate Formation ◽  
Initial Moment ◽  
Hydrate Shell ◽  
Surrounding Water ◽  
Vertical Coordinate ◽  
Associated Gas ◽  
First Case ◽  
Underwater Pipeline

The paper deals with the case of damage to the underwater pipeline through which oil and associated gas are transported. The process of oil and gas migration is described by the flow of a multiphase submerged jet. At the initial moment, the temperature of the incoming hydrocarbons, their initial velocity, the temperature of the surrounding water, the depth of the pipeline is known. The paper considers two cases of different initial parameters of hydrocarbon outflow from the pipeline. In the first case, the thermobaric environmental conditions correspond to the conditions of hydrate formation and stable existence. Such a case corresponds to the conditions of the hydrocarbons flow in the Gulf of Mexico. In the second case, hydrate is not formed. Such flows correspond to the cases of oil transportation through pipelines in the Baltic sea (for example, Nord stream–2). The process of hydrate formation will be characterized by the following dynamics of the bubble: first, it will be completely gas, then a hydrate shell (composite bubble) will begin to form on its surface, then the bubble will become completely hydrate, which will be the final stage. The integral Lagrangian control volume method will be considered for modeling the dynamics of hydrocarbon jet propagation. According to this method, the jet is considered as a sequence of elementary volumes. When modeling the jet flow, the laws of conservation of mass, momentum and energy for the components included in the control volume are taken into account. The equations are used taking into account the possible formation of hydrate. Thermophysical characteristics of hydrocarbons coming from the damaged pipeline for cases of deep-water and shallow-water pipeline laying are obtained. The trajectories of hydrocarbon migration, the dependence of the jet temperature and density on the vertical coordinate are analyzed.

Natural Gas Hydrate Formation Using Saline/Seawater for Gas Storage Application

2021 ◽  
Vol 35 (7) ◽  
pp. 5988-6002 ◽  
Author(s):  
Hari Prakash Veluswamy ◽  
Praveen Linga
Keyword(s):  
Natural Gas ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Gas Storage ◽  
Natural Gas Hydrate ◽  
Gas Hydrate Formation
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