scholarly journals One-Dimensional Study on Hydrate Formation from Migrating Dissolved Gas in Sandy Sediments

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1570
Author(s):  
Nan Li ◽  
Rezeye Rehemituli ◽  
Jie Zhang ◽  
Changyu Sun
Keyword(s):  
Colloidal Solution ◽  
Flow Direction ◽  
Hydrate Formation ◽  
Visual Observation ◽  
Dissolved Gas ◽  
Upward Migration ◽  
Migration Direction ◽  
Sediment Permeability ◽  
Sandy Sediments ◽  
Hydrate Reservoirs

Upward migration of gas-dissolved pore fluid is an important mechanism for many naturally occurring hydrate reservoirs. However, there is limited understanding in this scenario of hydrate formation in sediments. In this preliminary work, hydrate formation and accumulation from dissolved gas in sandy sediments along the migration direction of brine was investigated using a visual hydrate simulator. Visual observation was employed to capture the morphology of hydrates in pores through three sapphire tubes. Meanwhile, the resistivity evolution of sediments was detected to characterize hydrate distribution in sediments. It was observed that hydrates initially formed as a thin film or dispersed crystals and then became a turbid colloidal solution. With hydrate growth, the colloidal solution converted to massive solid hydrates. Electrical resistivity experienced a three-stage evolution process corresponding to the three observed hydrate morphologies. The results of resistivity analysis also indicated that the bottom–up direction of hydrate growth was consistent with the flow direction of brine, and two hydrate accumulation centers successively appeared in the sediments. Hydrates preferentially formed and accumulated in certain depths of the sediments, resulting in heterogeneous hydrate distribution. Even under low saturation, the occurrence of heterogeneous hydrates led to the sharp reduction of sediment permeability.

AE monitoring-based CO2 hydrate formation and its influences to hydrate-bearing sandy sediments

2021 ◽  
pp. 104292
Author(s):  
Xiaodong Zhao ◽  
Tingting Luo ◽  
Shengye Zhuang ◽  
Zejin Lai ◽  
Ruilin Li
Keyword(s):  
Hydrate Formation ◽  
Sandy Sediments

CO2 Capture and Storage from Flue Gas Using Novel Gas Hydrate-Based Technologies and Their Associated Impacts

2020 ◽  
Author(s):  
Aliakbar Hassanpouryouzband ◽  
Katriona Edlmann ◽  
Jinhai Yang ◽  
Bahman Tohidi ◽  
Evgeny Chuvilin
Keyword(s):  
Gas Hydrate ◽  
Flue Gas ◽  
Power Plants ◽  
Carbon Capture And Storage ◽  
Hydrate Formation ◽  
Gas Hydrate Formation ◽  
Experimental Apparatus ◽  
The Impact ◽  
And Storage ◽  
Hydrate Reservoirs

<p>Power plants emit large amounts of carbon dioxide into the atmosphere primarily through the combustion of fossil fuels, leading to accumulation of increased greenhouse gases in the earth’s atmosphere. Global climate changing has led to increasing global mean temperatures, particularly over the poles, which threatens to melt gas hydrate reservoirs, releasing previously trapped methane and exacerbating the situation.  Here we used gas hydrate-based technologies to develop techniques for capturing and storing CO<sub>2</sub> present in power plant flue gas as stable hydrates, where CO<sub>2</sub> replaces methane within the hydrate structure. First, we experimentally measured the thermodynamic properties of various flue gases, followed by modelling and tuning the equations of state. Second, we undertook proof of concept investigations of the injection of CO2 flue gas into methane gas hydrate reservoirs as an option for economically sustainable production of natural gas as well as carbon capture and storage. The optimum injection conditions were found and reaction kinetics was investigated experimentally under realistic conditions. Third, the kinetics of flue gas hydrate formation for both the geological storage of CO<sub>2</sub> and the secondary sealing of CH<sub>4</sub>/CO<sub>2</sub> release in one simple process was investigated, followed by a comprehensive investigation of hydrate formation kinetics using a highly accurate in house developed experimental apparatus, which included an assessment of the gas leakage risks associated with above processes.  Finally, the impact of the proposed methods on permeability and mechanical strength of the geological formations was investigated.</p>

scholarly journals Formation of submarine gas hydrates

1994 ◽  
Vol 41 ◽  
pp. 86-94
Author(s):  
V. Soloviev ◽  
G. D. Ginsburg
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Deep Sea ◽  
Hydrate Formation ◽  
Coarse Grained ◽  
Necessary Condition ◽  
Dissolved Gas ◽  
Scale Levels ◽  
Bottom Sampling ◽  
Gas Bearing

Submarine gas hydrates have been discovered in the course of deep-sea drilling (DSDP and ODP) and bottom sampling in many offshore regions. This paper reports on expeditions carried out in the Black, Caspian and Okhotsk Seas. Gas hydrate accumulations were discovered and investigated in all these areas. The data and an analysis of the results of the deep-sea drilling programme suggest that the infiltration of gas-bearing fluids is a necessary condition for gas hydrate accumulation. This is confirmed by geological observations at three scale levels. Firstly, hydrates in cores are usually associated with comparatively coarse-grained, permeable sediments as well as voids and fractures. Secondly, hydrate accumulations are controlled by permeable geological structures, i.e. faults, diapirs, mud volcanos as well as layered sequences. Thirdly, in the worldwide scale, hydrate accumulations are characteristic of continental slopes and rises and intra-continental seas where submarine seepages also are widespread. Both biogenic and cat­agenic gas may occur, and the gas sources may be located at various distances from the accumulation. Gas hydrates presumably originate from water-dissolved gas. The possibility of a transition from dissolved gas into hydrate is confirmed by experimental data. Shallow gas hydrate accumulations associated with gas-bearing fluid plumes are the most convenient features for the study of submarine hydrate formation in general. These accumulations are known from the Black, Caspian and Okhotsk Seas, the Gulf of Mexico and off northern California.

scholarly journals Improved imaging of gas hydrate reservoirs and their plumbing system using 2d elastic full waveform inversion

2021 ◽  
pp. 1-61
Author(s):  
Adnan Djeffal ◽  
Ingo A. Pecher ◽  
Satish C. Singh ◽  
Gareth J. Crutchley ◽  
Jari Kaipio
Keyword(s):  
Gas Hydrate ◽  
Waveform Inversion ◽  
Hydrate Formation ◽  
Velocity Model ◽  
Plumbing System ◽  
Low Velocity ◽  
Velocity Models ◽  
Full Waveform ◽  
Hydrate Reservoirs ◽  
Velocity Zone

Gas hydrates are ice-like crystalline materials that form under submarine environments of moderate pressure and low temperature. Another key factor to their formation is the abundance in gas supply from depth in addition to local biogenic gas. Detailed imaging and velocity analysis of the plumbing system of gas hydrates can provide confidence that amplitude anomalies in seismic data are related to gas hydrate accumulations. We have conducted 2D elastic full-waveform inversion (FWI) along a 14 km long segment of a 2D multichannel seismic profile to obtain a high-resolution velocity model of a hydrate system on the southern Hikurangi margin. We compare the FWI velocity model to previously published semblance- and tomography-based velocity models from the same data to explore how much more can be gained from the FWI. The FWI yielded a structurally more accurate velocity model that better delineated the low-velocity zone associated with free gas beneath the bottom simulating reflector (BSR) compared to the semblance- and tomography-based velocity models. Our results also find a lateral velocity inversion, that is, a narrow low-velocity zone surrounded by bands of higher velocities at a seaward-verging protothrust fault, which the two other methodologies failed to resolve. The FWI provides an improved lateral resolution making it an important tool when imaging the “plumbing” systems of gas hydrate reservoirs. In the southeastern limb of the anticline, our results find that the closely spaced landward-vergent protothrusts provide gas-charged fluids for hydrate formation above the BSR. Moreover, at the center of the anticline, our results find that a seaward-vergent protothrust fault appears to be acting as a conduit for gas-rich fluids into strata, although there is no accumulation of any significant hydrate above the BSR at the apex of the anticline. Our finding emphasizes the significance of densely spaced faults and fractures for providing gas for hydrate formation in the hydrate stability zone.

Equilibrium Conditions of Methane Hydrates in Seawater From Krishna-Godavari Basin, India

2021 ◽  
Vol 55 (2) ◽  
pp. 94-103
Author(s):  
Burla Sai Kiran ◽  
Kandadai Sowjanya ◽  
Pinnelli S.R. Prasad
Keyword(s):  
Alternative Energy ◽  
Saline Water ◽  
Hydrate Formation ◽  
Methane Hydrates ◽  
Equilibrium Conditions ◽  
Hydrate Dissociation ◽  
Clapeyron Equation ◽  
The Stability ◽  
Hydrate Reservoirs ◽  
Godavari Basin

Abstract Immense gas hydrate reservoirs have been reported in the Krishna-Godavari Basin, India. They mostly constitute methane gas and could serve as an alternative energy source. For efficient exploitation of methane from hydrates, it is crucial to know the region's stability conditions. The present study reports the stability and equilibrium conditions of methane hydrates, synthesized with seawater obtained from the Krishna-Godavari Basin. At Station MD161/02/GH, the water samples are collected at depths ranging from 500 to 1,500 m. The influence of salinity on methane hydrate formation and dissociation in the presence of seawater is established. The hydrate dissociation patterns in seawater and saline water (4 wt% NaCl) are similar and follow the phase equilibrium around 6 wt% NaCl. The identical dissociation behavior of the two systems ascertains seawater to have ~4 wt% salinity. The salinity concentration varies little with depth because the hydrate dissociation temperatures are the same for all the samples collected at the three depths. Using the Clausius-Clapeyron equation, dissociation enthalpies are calculated. The dissociation enthalpy in saline systems is about 6% higher. The hydrate growth kinetics is marginally faster in the saline system.

scholarly journals Modeling recovery of natural gas from hydrate reservoirs with carbon dioxide sequestration: Validation with Iġnik Sikumi field data

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Avinash V. Palodkar ◽  
Amiya K. Jana
Keyword(s):  
Carbon Dioxide ◽  
Natural Gas ◽  
Field Data ◽  
Enhanced Recovery ◽  
Pore Space ◽  
Exchange Process ◽  
Hydrate Formation ◽  
Model Parameters ◽  
Identification Technique ◽  
Hydrate Reservoirs

AbstractFundamental understanding of guest gas replacement in hydrate reservoirs is crucial for the enhanced recovery of natural gas and carbon dioxide (CO2) sequestration. To gain physical insight into this exchange process, this work aims at developing and validating a clathrate hydrate model for gas replacement. Most of the practical concerns associated with naturally occurring gas hydrates, including hydrate formation and dissociation in interstitial pore space between distributed sand particles in the presence of salt ions and in irregular nanometer-sized pores of those particles, irregularity in size of particles and shape of their pores, interphase dynamics during hydrate formation and decay, and effect of surface tension, are addressed. An online parameter identification technique is devised for automatic tuning of model parameters in the field. This model is employed to predict the laboratory-scale data for methane hydrate formation and decomposition. Subsequently, the model is validated with the field data of the Prudhoe Bay Unit on the Alaska North Slope during 2011 and 2012. In this Iġnik Sikumi field experiment, mixed CO2 (i.e., CO2 + N2) is used as a replacement agent for natural gas recovery. It is observed that the proposed formulation secures a promising performance with a maximum absolute average relative deviation (AARD) of about 2.83% for CH4, which is even lower, 0.84% for CO2 and 1.67% for N2.

Synthesis and Evaluation of a New Kind of Kinetic Hydrate Inhibitor

2017 ◽  
Vol 727 ◽  
pp. 781-790
Author(s):  
Ke Le Yan ◽  
Hong Xing Zhang ◽  
Ying Li ◽  
Bing Zou ◽  
An Shan Xiao ◽  
...  
Keyword(s):  
High Pressure ◽  
Gas Phase ◽  
Hydrate Formation ◽  
Onset Time ◽  
Visual Observation ◽  
Experimental Results ◽  
Synergic Effect ◽  
Morphological Behavior ◽  
Observation Method ◽  
Inhibition Performance

A new kind of kinetic hydrate inhibitor (KHI) named KL-1 as the ramification of poly (N-vinyl caprolactam) (PVCap), was synthesized successfully by use of precipitation polymerization. The hydrate inhibition performance of KL-1 was assessed in a high pressure sapphire cell, and the onset time of hydrate formation and maximum subcooling were determined by the visual observation method and compared with the commercial KHIs, including Inhibex 501 and VC-713. Meanwhile, the synergic effect between ethanol and KL-1 developed was also studied in this work. The experimental results show that the onset time of KL-1 measured increases with the increase of the dosage and decrease of subcooling. Compared with the system without kinetic hydrate inhibitor, the morphological behavior of hydrate crystals in the systems containing KL-1 is different, and the hydrate crystals only grow to the gas phase with the hydrate formation. Additionally, based on the measurement of inhibition time, the inhibition performance of KL-1 is superior to Inhibex 501 and VC-713, and shows higher maximum subcooling at the similar conditions. Finally, we also demonstrated that ethanol can be used as synergist to improve the performance of KL-1 remarkably at suitable dosage.

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