Gas production from unsealed hydrate-bearing sediments after reservoir reformation in a large-scale simulator

Fuel ◽  
2022 ◽  
Vol 308 ◽  
pp. 121957
Author(s):  
Yi-Fei Sun ◽  
Bo-Jian Cao ◽  
Jin-Rong Zhong ◽  
Jing-Yu Kan ◽  
Rui Li ◽  
...  
Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yilong Yuan ◽  
Tianfu Xu ◽  
Yingli Xia ◽  
Xin Xin

The effects of geologic conditions and production methods on gas production from hydrate-bearing sediments (HBS) have been widely investigated. The reservoir was usually treated as horizontal distribution, whereas the sloping reservoir was not considered. In fact, most strata have gradients because of the effects of geological structure and diagenesis. In this study, based on currently available geological data from field measurements in Shenhu area of the South China Sea, the effects of formation dip on gas production were investigated through depressurization using a horizontal well. The modeling results indicate that the strategy of horizontal well is an effective production method from the unconfined Class 2 HBS. The predicted cumulative volume of methane produced at the 1000 m horizontal well was 4.51 × 107 ST m3 over 5-year period. The hydrate dissociation behavior of sloping formation is sensitive to changes in the reservoir pressure. As in unconfined marine hydrate reservoir, the sloping formation is not conducive to free methane gas recovery, which results in more dissolved methane produced at the horizontal well. The obvious issue for this challenging target is relatively low exploitation efficiency of methane because of the recovery of very large volumes of water. Consequently, the development of the favorable well completion method to prevent water production is significantly important for realizing large scale hydrate exploitation in the future.


Energy ◽  
2021 ◽  
pp. 121183
Author(s):  
Nan Li ◽  
Jie Zhang ◽  
Ming-Ji Xia ◽  
Chang-Yu Sun ◽  
Yan-Sheng Liu ◽  
...  

Author(s):  
Ah-Ram Kim ◽  
Gye-Chun Cho ◽  
Joo-Yong Lee ◽  
Se-Joon Kim

Methane hydrate has been received large attention as a new energy source instead of oil and fossil fuel. However, there is high potential for geomechanical stability problems such as marine landslides, seafloor subsidence, and large volume contraction in the hydrate-bearing sediment during gas production induced by depressurization. In this study, a thermal-hydraulic-mechanical coupled numerical analysis is conducted to simulate methane gas production from the hydrate deposits in the Ulleung basin, East Sea, Korea. The field-scale axisymmetric model incorporates the physical processes of hydrate dissociation, pore fluid flow, thermal changes (i.e., latent heat, conduction and advection), and geomechanical behaviors of the hydrate-bearing sediment. During depressurization, deformation of sediments around the production well is generated by the effective stress transformed from the pore pressure difference in the depressurized region. This tendency becomes more pronounced due to the stiffness decrease of hydrate-bearing sediments which is caused by hydrate dissociation.


2021 ◽  
Author(s):  
Zhen Li ◽  
Thomas Kempka ◽  
Erik Spangenberg ◽  
Judith Schicks

<p>Natural gas hydrates are considered as one of the most promising alternatives to conventional fossil energy sources, and are thus subject to world-wide research activities for decades. Hydrate formation from methane dissolved in brine is a geogenic process, resulting in the accumulation of gas hydrates in sedimentary formations below the seabed or overlain by permafrost. The LArge scale Reservoir Simulator (LARS) has been developed (Schicks et al., 2011, 2013; Spangenberg et al., 2015) to investigate the formation and dissociation of gas hydrates under simulated in-situ conditions of hydrate deposits. Experimental measurements of the temperatures and bulk saturation of methane hydrates by electrical resistivity tomography have been used to determine the key parameters, describing and characterising methane hydrate formation dynamics in LARS. In the present study, a framework of equations of state to simulate equilibrium methane hydrate formation in LARS has been developed and coupled with the TRANsport Simulation Environment (Kempka, 2020) to study the dynamics of methane hydrate formation and quantify changes in the porous medium properties in LARS. We present our model implementation, its validation against TOUGH-HYDRATE (Gamwo & Liu, 2010) and the findings of the model comparison against the hydrate formation experiments undertaken by Priegnitz et al. (2015). The latter demonstrates that our numerical model implementation is capable of reproducing the main processes of hydrate formation in LARS, and thus may be applied for experiment design as well as to investigate the process of hydrate formation at specific geological settings.</p><p>Key words: dissolved methane; hydrate formation; hydration; python; permeability.</p><p>References</p><p>Schicks, J. M., Spangenberg, E., Giese, R., Steinhauer, B., Klump, J., & Luzi, M. (2011). New approaches for the production of hydrocarbons from hydrate bearing sediments. Energies, 4(1), 151-172, https://doi.org/10.3390/en4010151</p><p>Schicks, J. M., Spangenberg, E., Giese, R., Luzi-Helbing, M., Priegnitz, M., & Beeskow-Strauch, B. (2013). A counter-current heat-exchange reactor for the thermal stimulation of hydrate-bearing sediments. Energies, 6(6), 3002-3016, https://doi.org/10.3390/en6063002</p><p>Spangenberg, E., Priegnitz, M., Heeschen, K., & Schicks, J. M. (2015). Are laboratory-formed hydrate-bearing systems analogous to those in nature?. Journal of Chemical & Engineering Data, 60(2), 258-268, https://doi.org/10.1021/je5005609</p><p>Kempka, T. (2020) Verification of a Python-based TRANsport Simulation Environment for density-driven fluid flow and coupled transport of heat and chemical species. Adv. Geosci., 54, 67–77, https://doi.org/10.5194/adgeo-54-67-2020</p><p>Gamwo, I. K., & Liu, Y. (2010). Mathematical modeling and numerical simulation of methane production in a hydrate reservoir. Industrial & Engineering Chemistry Research, 49(11), 5231-5245, https://doi.org/10.1021/ie901452v</p><p>Priegnitz, M., Thaler, J., Spangenberg, E., Schicks, J. M., Schrötter, J., & Abendroth, S. (2015). Characterizing electrical properties and permeability changes of hydrate bearing sediments using ERT data. Geophysical Journal International, 202(3), 1599-1612, https://doi.org/10.1093/gji/ggv245</p>


Author(s):  
Mark McDougall ◽  
Ken Williamson

Oil and gas production in Canada’s west has led to the need for a significant increase in pipeline capacity to reach export markets. Current proposals from major oil and gas transportation companies include numerous large diameter pipelines across the Rocky Mountains to port locations on the coast of British Columbia (BC), Canada. The large scale of these projects and the rugged terrain they cross lead to numerous challenges not typically faced with conventional cross-country pipelines across the plains. The logistics and access challenges faced by these mountain pipeline projects require significant pre-planning and assessment, to determine the timing, cost, regulatory and environmental impacts. The logistics of pipeline construction projects mainly encompasses the transportation of pipe and pipeline materials, construction equipment and supplies, and personnel from point of manufacture or point of supply to the right-of-way (ROW) or construction area. These logistics movement revolve around the available types of access routes and seasonal constraints. Pipeline contractors and logistics companies have vast experience in moving this type of large equipment, however regulatory constraints and environmental restrictions in some locations will lead to significant pre-planning, permitting and additional time and cost for material movement. In addition, seasonal constraints limit available transportation windows. The types of access vary greatly in mountain pipeline projects. In BC, the majority of off-highway roads and bridges were originally constructed for the forestry industry, which transports logs downhill whereas the pipeline industry transports large equipment and pipeline materials in both directions and specifically hauls pipe uphill. The capacity, current state and location of these off-highway roads must be assessed very early in the process to determine viability and/or potential options for construction access. Regulatory requirements, environmental restrictions, season of use restrictions and road design must all be considered when examining the use of or upgrade of existing access roads and bridges. These same restrictions are even more critical to the construction of new access roads and bridges. The logistics and access challenges facing the construction of large diameter mountain pipelines in Western Canada can be managed with proper and timely planning. The cost of the logistics and access required for construction of these proposed pipeline projects will typically be greater than for traditional pipelines, but the key constraint is the considerable time requirement to construct the required new access and pre-position the appropriate material to meet the construction schedule. The entire project team, including design engineers, construction and logistics planners, and material suppliers must be involved in the planning stages to ensure a cohesive strategy and schedule. This paper will present the typical challenges faced in access and logistics for large diameter mountain pipelines, and a process for developing a comprehensive plan for their execution.


2018 ◽  
Vol 8 (1) ◽  
pp. 18
Author(s):  
Kees Bourgonje ◽  
Hubert J. Veringa ◽  
David M.J. Smeulders ◽  
Jeroen A. van Oijen

To speed up the torrefaction process in traditional torrefaction reactors, in particular auger reactors, the temperature of the reactor is substantially higher than the required torrefaction process temperature. This is due to the low heat conductivity of biomass. Unfortunately, the off-gas characteristics of biomass are very sensitive in the temperature window of 180-300°C which can cause a thermal runaway situation in which the process temperature exceeds the intended level. Due to this very sensitive temperature dependence of biomass pyrolysis and its accompanying gas production, a potential solution is to inject small amounts of air directly into the torrefaction reactor. It is found experimentally that this air injection can regulate the temperature of the biomass very rapidly compared to traditional temperature regulation by changing the reactor wall temperature. With this new torrefaction temperature control method, thermal runaway situations can be avoided and the temperature of the biomass in the reactor can be regulated better. Experiments with large beech wood samples show that the torrefaction reaction rate and the temperature in the core of the sample depend on the amount of injected air. Since the flow of combustible gasses (torr-gas) originating from the torrefaction process is very sensitive to temperature, the heat production by combusting the torr-gas can be controlled to some extent. This will result in both a more homogeneous torrefied product as well as a more stable processing of varying biomass types in large-scale torrefaction systems.


2016 ◽  
Vol 13 (15) ◽  
pp. 4595-4613 ◽  
Author(s):  
Alison L. Webb ◽  
Emma Leedham-Elvidge ◽  
Claire Hughes ◽  
Frances E. Hopkins ◽  
Gill Malin ◽  
...  

Abstract. The Baltic Sea is a unique environment as the largest body of brackish water in the world. Acidification of the surface oceans due to absorption of anthropogenic CO2 emissions is an additional stressor facing the pelagic community of the already challenging Baltic Sea. To investigate its impact on trace gas biogeochemistry, a large-scale mesocosm experiment was performed off Tvärminne Research Station, Finland, in summer 2012. During the second half of the experiment, dimethylsulfide (DMS) concentrations in the highest-fCO2 mesocosms (1075–1333 µatm) were 34 % lower than at ambient CO2 (350 µatm). However, the net production (as measured by concentration change) of seven halocarbons analysed was not significantly affected by even the highest CO2 levels after 5 weeks' exposure. Methyl iodide (CH3I) and diiodomethane (CH2I2) showed 15 and 57 % increases in mean mesocosm concentration (3.8 ± 0.6 increasing to 4.3 ± 0.4 pmol L−1 and 87.4 ± 14.9 increasing to 134.4 ± 24.1 pmol L−1 respectively) during Phase II of the experiment, which were unrelated to CO2 and corresponded to 30 % lower Chl a concentrations compared to Phase I. No other iodocarbons increased or showed a peak, with mean chloroiodomethane (CH2ClI) concentrations measured at 5.3 (±0.9) pmol L−1 and iodoethane (C2H5I) at 0.5 (±0.1) pmol L−1. Of the concentrations of bromoform (CHBr3; mean 88.1 ± 13.2 pmol L−1), dibromomethane (CH2Br2; mean 5.3 ± 0.8 pmol L−1), and dibromochloromethane (CHBr2Cl, mean 3.0 ± 0.5 pmol L−1), only CH2Br2 showed a decrease of 17 % between Phases I and II, with CHBr3 and CHBr2Cl showing similar mean concentrations in both phases. Outside the mesocosms, an upwelling event was responsible for bringing colder, high-CO2, low-pH water to the surface starting on day t16 of the experiment; this variable CO2 system with frequent upwelling events implies that the community of the Baltic Sea is acclimated to regular significant declines in pH caused by up to 800 µatm fCO2. After this upwelling, DMS concentrations declined, but halocarbon concentrations remained similar or increased compared to measurements prior to the change in conditions. Based on our findings, with future acidification of Baltic Sea waters, biogenic halocarbon emissions are likely to remain at similar values to today; however, emissions of biogenic sulfur could significantly decrease in this region.


2019 ◽  
Vol 3 (7) ◽  
pp. 1600-1622 ◽  
Author(s):  
Ji-Lu Zheng ◽  
Ya-Hong Zhu ◽  
Ming-Qiang Zhu ◽  
Kang Kang ◽  
Run-Cang Sun

The commercial production of advanced fuels based on bio-oil gasification could be promising because the cost-effective transport of bio-oil could promote large-scale implementation of this biomass technology.


Author(s):  
Zhaozhong Yang ◽  
Rui He ◽  
Xiaogang Li ◽  
Zhanling Li ◽  
Ziyuan Liu

The tight sandstone gas reservoir in southern Songliao Basin is naturally fractured and is characterized by its low porosity and permeability. Large-scale hydraulic fracturing is the most effective way to develop this tight gas reservoir. Quantitative evaluation of fracability is essential for optimizing a fracturing reservoir. In this study, as many as ten fracability-related factors, particularly mechanical brittleness, mineral brittleness, cohesion, internal friction angle, unconfined compressive strength (UCS), natural fracture, Model-I toughness, Model-II toughness, horizontal stress difference, and fracture barrier were obtained from a series of petrophysical and geomechanical experiments are analyzed. Taking these influencing factors into consideration, a modified comprehensive evaluation model is proposed based on the analytic hierarchy process (AHP). Both a transfer matrix and a fuzzy matrix were introduced into this model. The fracability evaluation of four reservoir intervals in Jinshan gas field was analyzed. Field fracturing tests were conducted to verify the efficiency and accuracy of the proposed evaluation model. Results showed that gas production is higher and more stable in the reservoir interval with better fracability. The field test data coincides with the results of the proposed evaluation model.


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