scholarly journals Multi-stage Depressurization Analysis of Subsea Production System Based on LedaFlow Software

2021 ◽  
Vol 329 ◽  
pp. 01019
Author(s):  
Wenfeng Chen ◽  
Pengpeng Ju ◽  
Xueyuan Wang ◽  
Dong Wang ◽  
Feilong Liu
Keyword(s):  
Low Temperature ◽  
South China Sea ◽  
Simulation Analysis ◽  
Hydrate Formation ◽  
Paper Briefly ◽  
Gas Field ◽  
Knock Out ◽  
Multi Stage ◽  
Subsea Production System ◽  
Temperature And Pressure

This paper briefly summarizes that during the depressurization operation in subsea pipeline for maintenance or prevention of hydrate formation, because the flare knock-out drum pump is designed for ambient temperature, and cannot deal with the low temperature fluid in the depressurization process. Therefore, the low temperature fluid needs to be heated in the knock-out drum to meet the temperature requirement of pump. In order to avoid the volume of low temperature fluid exceeding the surge volume of the flare knock-out drum, the concept of multi stage depressurization is innovatively proposed in this paper, which meets both the requirements of pump temperature and the surge volume of flare drum. Taking a gas field project in the South China Sea as an example, the simulation analysis of depressurization temperature and pressure is carried out by using different size of the blowdown valve. It provides a good reference for the similar project in future.

Development and Application of a New Style Low Dosage Hydrate Inhibitors

2014 ◽  
Author(s):  
Weixin Pang ◽  
Qingping Li ◽  
Fujie Sun
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
South China Sea ◽  
Field Test ◽  
Oil And Gas ◽  
Hydrate Formation ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Effective Technology ◽  
Low Dosage

The hydrate is an important issue that the flow assurance has to face in the oil and gas industry, especially in the deepwater area. With high pressure and low temperature, the hydrate formation is easily happened and leads to plug in the pipeline. In addition to the traditional thermodynamic inhibitor, the low dosage hydrate inhibitors (LDHI) has been increasing used as a costly effective technology for gas hydrate control. The LDHI include kinetic hydrate inhibitor (KHI) and anti-agglomerant (AA), the former can inhibit the hydrate formation in the pipeline, and the latter can prevent the agglomeration and plug of hydrate particles. According to the properties of oil and gas of South China Sea, a new KHI and AA were developed, a field test of the KHI has been undertaken and the results indicate that it can prevent the hydrate formation and plug in the pipeline well, the lab evaluation of the developed AA is in progress and the field test will be performed by the next year.

scholarly journals Characterization of Physical Field and Flow Assurance Risk Analysis of Subsea Cage-Sleeve Throttling Valve

2021 ◽  
Vol 9 ◽  
Author(s):  
Donglei Jiang ◽  
Wenbo Meng ◽  
Yi Huang ◽  
Yi Yu ◽  
Youwei Zhou ◽  
...  
Keyword(s):  
Low Temperature ◽  
Production System ◽  
Oil And Gas ◽  
Negative Impact ◽  
Hydrate Formation ◽  
Simulation Method ◽  
Gas Production ◽  
Oil And Gas Development ◽  
Regular Production ◽  
Subsea Production System

The subsea production system is presently widely adopted in deepwater oil and gas development. The throttling valve is the key piece of equipment of the subsea production system, controlling the safety of oil and gas production. There are many valves with serious throttling effect in the subsea X-tree, so the hydrate formation risk is relatively high. In this work, a 3D cage-sleeve throttling valve model was established by the numerical simulation method. The temperature and pressure field of the subsea throttling valve was accurately characterized under different prefilling pressure, throttling valve opening degree, and fluid production. During the well startup period, the temperature of the subsea pipeline is low. If the pressure difference between the two ends of the pipeline is large, the throttling effect is obvious, and low temperature will lead to hydrate formation and affect the choice of throttling valve material. Based on the analysis of simulation results, this study recommends that the prefilling pressure of the subsea pipe is 7–8 MPa, which can effectively reduce the influence of the throttling effect so that the downstream temperature can be kept above 0°C. At the same time, in regular production, a suitable choke size is opened to match the production, preventing the serious throttling effect from a small choke size. According to the API temperature rating table, the negative impact of local low temperature caused by the throttling effect on the temperature resistance of the pipe was considered, and the appropriate subsea X-tree manifold material was selected to ensure production safety. The hydrate phase equilibrium curve is used to estimate the hydrate formation risk under thermodynamic conditions. Hydrate inhibitors are injected to ensure downstream flow safety.

scholarly journals Gas Hydrate Formation Risk and Prevention for the Development Wells in the Lingshui Gas Field in South China Sea

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Donglei Jiang ◽  
Yi Yu ◽  
Yi Huang ◽  
Wenbo Meng ◽  
Jianbo Su ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Deep Water ◽  
Hydrate Formation ◽  
The South China Sea ◽  
The South ◽  
Gas Field ◽  
Gas Well ◽  
China Sea ◽  
Water Gas

Hydrate formation risk is an important challenge in the development of deep-water gas field. Considering the characteristics of the Lingshui (LS) gas field in the South China Sea and the difference of well structures, a model for calculating wellbore temperature and pressure in deep-water gas production well is proposed and verified by the field data. Combining the hydrate equilibrium models with varied gas components, the prediction method of hydrate formation region in deep-water gas well in the South China Sea is obtained. The hydrate formation regions under different operating conditions for a deep-water gas well in the South China Sea were given by the proposed model. The results show that no hydrate formation risk exists in the production operation, but the risk exists in the shut-in and testing operations. Meanwhile, the determination of the hydrate inhibitor injection parameters during the testing operation is studied, and the influence of the inhibitors’ injection concentration and pressure on preventing gas hydrates is analyzed. This work provides useful advice for the prediction and prevention of hydrate formation risk in the development of deep-water gas fields, especially in the South China Sea.

scholarly journals Potential Use of Phoenix canariensis Biomass in Binderless Particleboards at Low Temperature and Pressure

BioResources ◽  
2017 ◽  
Vol 12 (3) ◽  
Author(s):  
Antonio Ferrández-García ◽  
Manuel Ferrández-Villena ◽  
Clara E. Ferrández-García ◽  
Teresa García-Ortuño ◽  
María T. Ferrández-García
Keyword(s):  
Low Temperature ◽  
Phoenix Canariensis ◽  
Temperature And Pressure ◽  
Potential Use

scholarly journals Generalized optimizations of two-stage forging of micro/meso copper fastener

2018 ◽  
Vol 185 ◽  
pp. 00002
Author(s):  
Shih-Hsien Lin ◽  
Un-Chin Chai ◽  
Gow-Yi Tzou ◽  
Dyi-Cheng Chen
Keyword(s):  
Simulation Analysis ◽  
Effective Strain ◽  
Cold Forging ◽  
Two Stage ◽  
Forming Simulation ◽  
Multi Stage ◽  
Element Simulation ◽  
Die Stress ◽  
Stress Optimization ◽  
Forging Force

Three are generalized simulation optimizations considering the forging force, the die stress, and the dual-goals in two-stage forging of micro/meso copper fastener. Constant shear friction between the dies and workpiece is assumed to perform multi-stage cold forging forming simulation analysis, and the Taguchi method with the finite element simulation has been used for mold-and-dies parameters design simulation optimizations considering the forging force, die stress, and dual-goals. The die stress optimization is used to explore the effects on effective stress, effective strain, velocity field, die stress, forging force, and shape of product. The influence rank to forging process of micro/meso copper fastener for three optimizations can be determined, and the optimal parameters assembly consider die stress can be obtained in this study. It is noted that the punch design innovation can reduce the forging force and die stress.

The Storing Properties of Electric Energy in Bone

2011 ◽  
Vol 493-494 ◽  
pp. 170-174
Author(s):  
Rumi Hiratai ◽  
Miho Nakamura ◽  
Akiko Nagai ◽  
Kimihiro Yamashita
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Electric Fields ◽  
Electric Energy ◽  
Depolarization Current ◽  
Thermally Stimulated Depolarization Current ◽  
High Temperature And Pressure ◽  
Temperature And Pressure ◽  
Thermally Stimulated Depolarization ◽  
Inorganic Components

We have shown that hydroxyapatite (HA), which characteristics were similar to those of bone’s inorganic components, had polarization capability and was possible to accumulate electricity under high temperature and pressure. Then, we presumed that bones had polarization capability which enabled electrical storage and conducted the experiment to measure the polarization capability of bones using rabbit’s femurs. After preparing and polarizing bone samples using KOH treatment (koh), KOH and baking treatment (koh+bake) and decalcification treatment (decalcification) as well as the bone without any treatment (untreat), quantitative amounts of stored charge in samples were determined by thermally stimulated depolarization current (TSDC) measurement of these samples. Under the condition of 400 °C for 1 h with the electric fields of 5kV/cm, samples of koh, koh+bake, and untreat showed polarization capability. In addition, under the polarization condition of 37 °C for 1 hour with the electric fields of 5kV/cm, all samples showed polarization capability. Those findings can be summarized that bones have the polarization capability which enables electrical storage and polarization of bones is possible even under the low temperature condition, which was at 37 °C in our experiment, where polarization is impossible for HA.

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