Numerical Analysis of the Behavior of Gas Hydrate Layers After Cementing Operations

2021 ◽  
Author(s):  
Sukru Merey ◽  
Tuna Eren ◽  
Can Polat
Keyword(s):  
Numerical Simulations ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Cement Hydration ◽  
Nankai Trough ◽  
Heat Of Hydration ◽  
Production Test ◽  
Hydrate Saturation ◽  
Gas Channeling ◽  
Heat Released

Abstract Since the 2000s, the number of gas hydrate wells (i.e., exploration wells, production test wells) has increased. Moreover, in the marine environment, gas hydrate zones are drilled in conventional hydrocarbon wells. Different than conventional hydrocarbon wells, the heat released with cement hydration cannot be ignored because gas hydrates are heat sensitive. In this study, by analyzing different cement compositions (conventional cement compositions and novel low-heat of hydration cement), it is aimed to investigate the effect of the heat of cement hydration on gas hydrate zones near the wellbore. For this purpose, numerical simulations with TOUGH+HYDRATE simulator were conducted in the conditions of the Nankai Trough gas hydrates. According to the numerical simulations in this study, if the increase in temperature in the cemented layer is above 30°C, significant gas hydrate dissociation occurs, and free gas evolved in the porous media. This might cause gas channeling and poor cement bond. The heat released with cement hydration generally affects the interval between the cemented layer and 0.25 m away from the cemented layer. Within a few days after cementing, pressure, temperature, gas hydrate saturation, and gas saturation returned to almost their original values.

Comparison of Simplistic and Geologically Descriptive Production Modeling for Natural-Gas Hydrate by Depressurization

SPE Journal ◽  
2019 ◽  
Vol 24 (02) ◽  
pp. 563-578 ◽  
Author(s):  
Yilong Yuan ◽  
Tianfu Xu ◽  
Yingli Xia ◽  
Xin Xin
Keyword(s):  
Gas Hydrate ◽  
History Matching ◽  
Nankai Trough ◽  
Flow Behavior ◽  
Test Site ◽  
Gas Production ◽  
Production Test ◽  
Hydrate Reservoir ◽  
Hydrate Saturation ◽  
Production Modeling

Summary Marine-gas-hydrate-drilling exploration at the Eastern Nankai Trough of Japan revealed the variable distribution of hydrate accumulations, which are composed of alternating beds of sand, silt, and clay in sediments, with vertically varying porosity, permeability, and hydrate saturation. The main purposes of this work are to evaluate gas productivity and identify the multiphase-flow behavior from the sedimentary-complex hydrate reservoir by depressurization through a conventional vertical well. We first established a history-matching model by incorporating the available geological data at the offshore-production test site in the Eastern Nankai Trough. The reservoir model was validated by matching the fluid-flow rates at a production well and temperature changes at a monitoring well during a field test. The modeling results indicate that the hydrate-dissociation zone is strongly affected by the reservoir heterogeneity and shows a unique dissociation front. The gas-production rate is expected to increase with time and reach the considerable value of 3.6 × 104 std m3/d as a result of the significant expansion of the dissociation zone. The numerical model, using a simplified description of porosity, permeability, and hydrate saturation, leads to significant underestimation of gas productivity from the sedimentary-complex hydrate reservoir. The results also suggest that the interbedded-hydrate-occurrence systems might be a better candidate for methane (CH4) gas extraction than the massive hydrate reservoirs.

Mechanical Response of Reservoir and Well Completion of the First Offshore Methane-Hydrate Production Test at the Eastern Nankai Trough: A Coupled Thermo-Hydromechanical Analysis

SPE Journal ◽  
2018 ◽  
Vol 24 (02) ◽  
pp. 531-546 ◽  
Author(s):  
Jun Yoneda ◽  
Akira Takiguchi ◽  
Toshimasa Ishibashi ◽  
Aya Yasui ◽  
Jiro Mori ◽  
...  
Keyword(s):  
Gas Hydrate ◽  
Mechanical Response ◽  
Nankai Trough ◽  
Water Pressure ◽  
Compressive Force ◽  
Gas Production ◽  
Production Test ◽  
Frictional Stress ◽  
Well Completion ◽  
Hydrate Saturation

Summary During gas production from offshore gas-HBS, there are concerns regarding the settlement of the seabed and the possibility that frictional stress will develop along the production casing. This frictional stress is caused by a change in the effective stress induced by water movement caused by depressurization and dissociation of hydrate as well as gas generation and thermal changes, all of which are interconnected. The authors have developed a multiphase-coupled simulator by use of a finite-element method named COTHMA. Stresses and deformation caused by gas-hydrate production near the production well and deep seabed were predicted using a multiphase simulator coupled with geomechanics for the offshore gas-hydrate-production test in the eastern Nankai Trough. Distributions of hydrate saturation, gas saturation, water pressure, gas pressure, temperature, and stresses were predicted by the simulator. As a result, the dissociation of gas hydrate was predicted within a range of approximately 10 m, but mechanical deformation occurred in a much wider area. The stress localization initially occurred in a sand layer with low hydrate saturation, and compression behavior appeared. Tensile stress was generated in and around the casing shoe as it was pulled vertically downward caused by compaction of the formation. As a result, the possibility of extensive failure of the gravel pack of the well completion was demonstrated. In addition, in a specific layer, where a pressure reduction progressed in the production interval, the compressive force related to frictional stress from the formation increased, and the gravel layer became thin. Settlement of the seafloor caused by depressurization for 6 days was within a few centimeters and an approximate 30 cm for 1 year of continued production.

Numerical Study on Eastern Nankai Trough gas Hydrate Production Test

2014 ◽  
Author(s):  
Mingliang Zhou ◽  
Kenichi Soga ◽  
Ermao Xu ◽  
Shun Uchida ◽  
Koji Yamamoto
Keyword(s):  
Gas Hydrate ◽  
Nankai Trough ◽  
Numerical Study ◽  
Production Test

THE GAS HYDRATE OF BROMOCHLORODIFLUOROMETHANE

1960 ◽  
Vol 38 (2) ◽  
pp. 208-221 ◽  
Author(s):  
D. N. Glew
Keyword(s):  
Experimental Study ◽  
Thermodynamic Functions ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Saturation Pressure ◽  
Stoichiometric Compound ◽  
Pressure Data ◽  
Systematic Treatment ◽  
Hydrate Saturation ◽  
Thermodynamic Equations

An experimental study has been made of the saturation pressure – temperature lines of liquid bromochlorodifluoromethane, liquid bromochlorodiflucromethane – water, bromochlorodifluoromethane hydrate – water, and bromochlorodifluoromethane hydrate – ice systems, for which the characteristic equations are given. Two quadruple points for the hydrate systems have been located and solubilities of water in bromochlorodifluoromethane and bromochlorodifluoromethane in water determined. A systematic treatment of gas hydrate saturation pressure data to yield thermodynamic equations is indicated, and the thermodynamic functions for bromochlorodifluoromethane hydrate and its phase reactions are tabulated. Bromochlorodifluoromethane hydrate is shown to be a stoichiometric compound, and its thermodynamic functions are considered in relation to those of other gas hydrates.

Gas hydrate saturation and distribution in the Kumano Forearc Basin of the Nankai Trough

2017 ◽  
Vol 48 (2) ◽  
pp. 137-150 ◽  
Author(s):  
Jihui Jia ◽  
Takeshi Tsuji ◽  
Toshifumi Matsuoka
Keyword(s):  
Gas Hydrate ◽  
Nankai Trough ◽  
Forearc Basin ◽  
Hydrate Saturation

Experimental Study on Dynamic Elastic Properties of Gas Hydrate Bearing Sediments

2012 ◽  
Vol 446-449 ◽  
pp. 1396-1399
Author(s):  
Ling Dong Li ◽  
Yuan Fang Cheng ◽  
Xiao Jie Sun
Keyword(s):  
Elastic Properties ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hot Spot ◽  
Confining Pressure ◽  
Measuring System ◽  
Fundamental Parameters ◽  
Hydrate Saturation ◽  
Hydrate Bearing Sediments

As a kind of emerging energy with massive reserves, natural gas hydrates are becoming the hot spot of global research. The elastic properties of gas hydrate bearing sediments (HBS) are the fundamental parameters for gas hydrates exploration and resource evaluations. As the original coring in HBS is difficult and expensive, experimental method is important to study the problem. An acoustic wave in-situ measuring system for HBS was developed. Using the in-situ method, hydrate bearing rock samples of different hydrate saturation were synthesized, of which the supersonic wave measurement was carried out under different confining pressure. According to the elasticity theory, the dynamic elastic parameters were obtained using the measured ultrasonic wave velocity. The results show that compressional and shear waves increase with the confining pressure and hydrate saturation increasing, and so the dynamic elastic modulus is.

Soaking effects on CH4-CO2 replacement efficiency in gas hydrates

2020 ◽  
Author(s):  
Jongwon Jung ◽  
Jaeeun Ryou ◽  
Joo Yong Lee ◽  
Riyadh I AI-Raoush ◽  
Khalid Alshibli ◽  
...  
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Production Efficiency ◽  
Gas Permeability ◽  
Gas Production ◽  
Production Methods ◽  
Injection Method ◽  
Development Organization ◽  
Replacement Method ◽  
Hydrate Saturation

<p>Gas hydrates are potential energy resources which can be formed at low temperature and high pressure. The number of recoverable gas hydrates are limited due to the specific temperature, pressure conditions and technical limitations of gas production. Various production methods have been studied around the world to overcome these technical limitations. Gas production methods from gas hydrates are divided into methods of dissociating gas hydrates and non-dissociating gas hydrates. The dissociation methods including depressurization method, thermal injection method, and chemical inhibitor injection method can decrease in effective stress of the ground due to phase conversion. On the other hand, CH<sub>4</sub>-CO<sub>2 </sub>replacement method is geomechanically stable because it does not dissociate gas hydrates. Also, CH<sub>4</sub>-CO<sub>2 </sub>replacement method has the advantage of sequestering carbon dioxide while producing methane. However, CH<sub>4</sub>-CO<sub>2</sub> replacement method has the disadvantage such as low production efficiency and understanding kinetics of gas production. In this study, soaking, gas permeability of gas hydrate layer and hydrate saturation are considered in order to promote the production efficiency of CH<sub>4</sub>-CO<sub>2</sub> replacement method. Results show that production efficiency increases with the number of soaking process, the higher gas permeability and hydrate saturation. According to the experimental results in this study, the production efficiency can be increased by considering the soaking time, procedure and selecting the proper gas hydrates site.</p><p>Acknowledgement</p><p>This work is supported by the Korea Agency for Infrastructure Technology Advancement(KAIA) grant funded by the Ministry of Land, Infrastructure and Transport (Grant 20CTAP-C152100-02). Also, it is supported by partial funding from NPRP grant # NPRP8-594-2-244 from the Qatar national research fund (a member of Qatar Foundation) and  the Ministry of Trade, Industry, and Energy (MOTIE) through the Project “Gas Hydrate Exploration and Production Study (20-1143)” under the management of the Gas Hydrate Research and Development Organization (GHDO) of Korea and the Korea Institute of Geoscience and Mineral Resources (KIGAM).</p>

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