System response to gas production from a heterogeneous hydrate accumulation at the UBGH2-6 site of the Ulleung basin in the Korean East Sea

Moridis, George J.; Reagan, Matthew T.; Queiruga, Alejandro F.; Kim, Se-Joon

doi:10.1016/j.petrol.2019.03.058

Cited by 29 publications

(6 citation statements)

References 17 publications

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“…Moridis et al studied the feasibility of gas production of a vertical well and the sensitivity of heterogeneity in reservoir properties in the Ulleung Basin in the Korean East Sea. 26 It showed that the low gas production rates and relatively large water production rates were expected for the lowpermeability sediment. Huang et al employed numerical simulation to estimate the production potential of four sites in the Shenhu area.…”

Section: Introductionmentioning

confidence: 99%

“…It was found that the gas production rate decreased at first terms, then increased, and finally decreased again in the long-term gas production. Moridis et al studied the feasibility of gas production of a vertical well and the sensitivity of heterogeneity in reservoir properties in the Ulleung Basin in the Korean East Sea . It showed that the low gas production rates and relatively large water production rates were expected for the low-permeability sediment.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Analysis of Production Behaviors and Permeability Characteristics on the Second Gas Hydrate Production Test in the South China Sea

Xiao

et al. 2022

Energy Fuels

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The dissociation of hydrate plays an important role in restructuring the pore space and controlling the permeability, which determines the gas recovery from offshore hydrate reservoir. Based on the second production test in the Shenhu area, China South Sea (2020), this study investigates the production behaviors and permeability characteristics of the hydrate reservoir by using the depressurization method with a single horizontal well. A permeability adjustment model is proposed to revise the absolute permeability, and then the changes in permeability characteristics with hydrate dissociation are analyzed on a field scale for the first time. The dissociation of the hydrate can significantly improve the intrinsic permeability, thus promoting fluid flow and gas production efficiency. The simulation results show that it achieves a cumulative gas production of 89.41 × 104 m3 for 30 days, which is very close to the second production test of 86.14 × 104 m3. Also, the produced gas-to-water ratio is in the range of 15–55, and the ratio of dissociation-originating gas to the cumulative gas production reaches 0.50 for the 30 day simulation. The invasion of the underlying water with relatively high temperatures can promote the rate of hydrate dissociation in the bottom of the hydrate-bearing sediment due to the poor thermodynamic stability. The sensitivity analyses also indicate that the parameters of absolute permeability, irreducible gas saturation, and irreducible water saturation have significant influences on gas production. These insights verify the feasibility of the depressurization with the horizontal well and can be beneficial for future hydrate exploration.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of Production Behaviors and Permeability Characteristics on the Second Gas Hydrate Production Test in the South China Sea

Xiao

et al. 2022

Energy Fuels

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“…In this region, gas hydrate production via depressurization is under investigation, owing to its technical reliability and efficiency in accelerating hydrate dissociation reactions. Various studies on depressurization methods have been conducted, targeting UBGH2-6 [14][15][16][17]. Moridis et al [14] employed the TOUGH + HYDRATE simulator, developed by the Lawrence Berkeley National Laboratory (LBNL), to analyze gas hydrate production trends and simulate formation subsidence linked to depressurization.…”

Section: Introductionmentioning

confidence: 99%

“…Moridis et al [14] employed the TOUGH + HYDRATE simulator, developed by the Lawrence Berkeley National Laboratory (LBNL), to analyze gas hydrate production trends and simulate formation subsidence linked to depressurization. Moridis et al [15] investigated the feasibility of gas hydrate production by considering the properties and conditions of UBGH2-6. They examined the sensitivity of the system to heterogeneity in permeability, porosity, and initial hydrate saturation and assessed the geomechanical response to a 14-d production period.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Production Performance and Uncertainty in the UBGH2-6 Gas Hydrate Reservoir, Ulleung Basin

Kim,

Lee

2024

JMSE

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This study delineates the intricate dynamics of gas hydrate production in the UBGH2-6 reservoir, located in the Ulleung Basin, by deploying a comprehensive simulation model. By integrating a sensitivity analysis with Latin hypercube sampling-based Monte Carlo simulations, we evaluated the influences on gas and water production and explored the underlying uncertainties within this gas hydrate reservoir. The simulation model revealed significant findings, including the production of approximately 440 t of gas and 34,240 t of water, facilitated by a depressurization strategy at 9 MPa for a year. This highlights the pivotal roles of porosity, permeability, and thermal properties in enhancing production rates and influencing hydrate dissociation processes. Sensitivity analysis of 19 parameters provides insights into their impact on production, identifying the key drivers of increased production rates. Furthermore, uncertainty analysis examined 300 reservoir models, utilizing statistical percentiles to quantify uncertainties, projecting a median gas production of approximately 455 t. This study identifies critical factors affecting gas hydrate production and offers valuable insights for future exploration and exploitation strategies, making a significant contribution to the field of gas hydrate research.

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“…From the logging-while-drilling data, it can be seen that the hydrate reservoir’s inner physical parameters have obvious three-dimensional (3D) spatial distribution characteristics and is an important factor that influences hydrate resource occurrence and distribution. The past research work on the description of the hydrate reservoir model was quite easy, and it mainly relied on vertical parameter distribution of single well logging data to describe the distribution characteristics of the reservoir’s various properties. − The conceptual model based on this ignored the heterogeneity of the hydrate reservoir. The hydrate reservoir exploitation involves the phase change of hydrate decomposition, heat transfer, multiphase flow, skeleton deformation, and so on and is the multifield coupling of the underground fluid flow field, temperature field, and stress field.…”

Section: Introductionmentioning

confidence: 99%

Study on Gas Hydrate Reservoir Reconstruction for Enhanced Gas Production in the Shenhu Area of the South China Sea Based on a 3D Heterogeneous Geological Model

Xin

et al. 2022

Energy Fuels

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Natural gas hydrate (NGH) has the huge exploitation potential for clean energy in the current world energy pattern. Its total organic carbon storage is about twice the sum of carbon content of oil, gas, and coal and hence attracts the attention of the world. China has carried out some gas hydrate exploitation works and delineation of three gas hydrate deposits whose reserve scale is over 100 billion cubic meters, and the NGH resource is abundant. The NGH reservoir in the South China Sea is of low porosity and permeability, is unconsolidated, has poor cementation, and is easy to fragment in hydrate production. On the one hand, the condition of low porosity and permeability around the well would severely reduce the production effect; on the other hand, the hydrate decomposition would more easily bring wellbore instability caused by stratum stress change. Therefore, to achieve safe and efficient exploitation of NGH, proper reservoir reconstruct technology needs to be chosen for enhancing the reservoir’s permeability and stability. This paper chose the Shenhu area of South China Sea as the research area, constructed the three-dimensional heterogeneous geological model of hydrate-bearing sediments which can be approximated realistically to depict, then used high-pressure jet grouting (HPJG) technology to reconstruct the hydrate reservoir, optimized the grouting hole direction, location, and spacing, and assessed the productivity increasing effect. The research results show the following: (a) Because of the higher hydrate saturation (SH) and lower permeability (k) around the well, the HPJG in the vertical direction was profitable for reservoir productivity. (b) Considering the heterogeneous SH and k in the horizontal direction, the HPJG in the front of the horizontal well was profitable for the reservoir productivity. (c) The HPJG spacing needs to be properly designed in combination with the absolute standard (V P), the relative standard (R GM), and the specific production index (J). (d) Under the conditions of this paper setting, the optimal HPJG reconstruction scheme is as follows: the HPJG in the vertical direction was arranged at the front of the horizontal well, and the spacing between the holes was 10 m. The productivity after reconstruction ranged up to 55.69% compared with before.

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System response to gas production from a heterogeneous hydrate accumulation at the UBGH2-6 site of the Ulleung basin in the Korean East Sea

Cited by 29 publications

References 17 publications

Numerical Analysis of Production Behaviors and Permeability Characteristics on the Second Gas Hydrate Production Test in the South China Sea

Numerical Analysis of Production Behaviors and Permeability Characteristics on the Second Gas Hydrate Production Test in the South China Sea

Assessment of Production Performance and Uncertainty in the UBGH2-6 Gas Hydrate Reservoir, Ulleung Basin

Study on Gas Hydrate Reservoir Reconstruction for Enhanced Gas Production in the Shenhu Area of the South China Sea Based on a 3D Heterogeneous Geological Model

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