Gas Hydrate Field Research Articles

Numerical Simulation of Vertical Well Depressurization with Different Deployments of Radial Laterals in Class 1-Type Hydrate Reservoir

Gas production efficiency is a key indicator in the commercial development of natural gas hydrates (NGHs). Based on the data from the first natural gas hydrate field test production in the Shenhu Sea area of China, the gas production capability of Class 1-type hydrate reservoirs was numerically evaluated by vertical well depressurization with different deployment schemes for radial laterals. The results showed that the radial laterals can effectively improve production efficiency and that the radial laterals deployed at the three-phase layer (TPL) have the best production performance. Compared with the single vertical well production, the completion length of the radial laterals is 150 m with a radius of 0.05 m, and the production pressure difference is set to 6 MPa. The cumulative gas production Vg reaches up to 594.10 × 104 ST m3, increased by about 208.53% after 360 days of production, which provides a reference for the development of natural gas hydrates with radial jet drilling (RJD) technology.

Application of Dual Horizontal Well Systems in the Shenhu Area of the South China Sea: Analysis of Productivity Improvement

The horizontal well technology was successfully applied in the Chinese second natural gas hydrate (NGH) field test in the Shenhu area of the South China Sea in 2020. However, the results show that the threshold for commercial exploitation has not been broken, judging from daily gas production and cumulative gas production. Consequently, the paper presents the effects of dual horizontal well systems for exploitation in this area. The NGH reservoir model in the Shenhu area was established with CMG software. The influence of various layout options and various spacing of dual horizontal well systems on the production capacity was investigated. Further, we simulated the production effect of dual horizontal well systems joint auxiliary measures, such as well wall heating, heat injection, etc. The results show that the production capacity of dual horizontal well systems increased by about 1.27~2.67 times compared with that of a single horizontal well. The daily gas production will drop significantly, no matter which method was used, when exploitation lasts for about 200 d. Meanwhile, well wall heating and heat injection have limited effects on promoting production capacity. In conclusion, attention was drawn to the fact that the synergistic effect could be fully exerted to accelerate NGH dissociation when dual horizontal well systems are applied. The NGH reservoirs in the Shenhu area may be more suitable for short-term exploitation. The research results of this paper can provide a reference for the exploitation of the Shenhu area.

Reservoir stimulation of marine natural gas hydrate-a review

Low production rate, limited recovery range, and short period of stabilized production of natural gas hydrate (NGH) field trials indicate a large gap to commercial production. To improve the efficiency of gas recovery from NGH reservoir, a large number of studies on reservoir stimulation have been reported. In this review, various aspects of reservoir fracability, including brittleness, fracture toughness, and fracability index model are comprehensively analyzed to provide an overall view on the generation of fractures in marine NGH reservoir. The main reservoir stimulation methods are summarized into four aspects: hydraulic fracturing, jet breaking, overlying layer modification and split grouting, of which the working principle, advantages, and limitations are highlighted. It indicates split grouting is the most promising method for achieving two goals of both reservoir skeleton reinforcement and permeability enhancement. Besides, the production enhancement by reservoir stimulation of non-diagenetic hydrate reservoir should be further evaluated considering the evolution of artificial seepage channels during hydrate decomposition. Finally, further developments are suggested to obtain reliable results of the fracability of NGH reservoir, bridge the gap of reservoir stimulation between concept design and practical application, and highlight the combination between reservoir stimulation and NGH reservoir stability for safe and efficient gas production.

Visualization of shallow subseafloor fluid migration in a shallow gas hydrate field using high-resolution acoustic mapping and ground-truthing and their implications on the formation process: a case study of the Sakata Knoll on the eastern margin of the Sea of Japan

Acoustic mapping enables an understanding of the surface distribution of shallow gas hydrate (GH) and related products. Acoustically characteristic materials such as fluid-seepage-related methane-derived authigenic carbonate and/or shallow GHs, may be widely distributed beneath the shallow seafloor of the Sakata Knoll. High-amplitude reflectors over the knoll are the top of gas-bearing permeable layers and connect to the reverse fault at the foot of the knoll. Shallow GH and bacterial mats were observed at the high-amplitude layer cut by depression and/or the locally disturbed seafloor. Acoustic blanking zones observed on the sub-bottom profiler sections are current gas migration routes from the depth to the seafloor. Optical observations indicate that fluid seepage is not active in the current seafloor, and it is not necessarily observed above the acoustic blanking zones or shallow faults reaching the seafloor. In the Sakata Knoll, the tectonically formed reverse fault and gas-bearing permeable layers play more important roles in fluid migration from depth to the summit area of the knoll compared to acoustic blanking and shallow faults. The depression at the summit area of the Sakata Knoll was formed by the dissociation of a shallow GH at around the last glacial maximum. Limited fluid seepage is currently witnessed within and around the depression and it is less extensive than that in the past. Such knolls, with tectonically formed large faults and an anticline are abundant in the area and they can be good reservoirs for shallow GH along the eastern margin of the Sea of Japan.

Mini Review on Application and Outlook of In Situ Raman Spectrometry in Gas Hydrate Research

Natural gas hydrates have drawn much attention as a result of their considerable reserves, clean energy, and global distribution. Some new technologies, such as energy storage and transportation, gas separation, and desalination, have been developed via forming hydrates. The structure, composition, and cage occupancy of gas hydrates and kinetics of hydrate formation and dissociation are crucial in flow assurance and the applications mentioned above. In view of its dependable, efficient, and non-destructive features, in situ Raman spectroscopy is a typical and popular measuring technique in gas hydrates. In this mini review, the application and microscopic characterization using in situ Raman spectroscopy in the gas hydrate field were reviewed, including how to use Raman spectroscopy to identify the structure and molar composition of hydrate and how to offer in situ information on the kinetics of formation, decomposition, replacement, and molecular diffusion at the molecular level. The challenges and perspectives on future studies of in situ Raman spectrometry have been proposed.

Diatom influence on the production characteristics of hydrate-bearing sediments: Examples from Ulleung Basin, offshore South Korea

The Ulleung Basin Gas Hydrate field expeditions in 2007 (UBGH1) and 2010 (UBGH2) sought to assess the Basin's gas hydrate resource potential. Coring operations in both expeditions recovered evidence of gas hydrate, primarily as fracture-filling (or vein type) morphologies in mainly silt-sized, fine-grained sediment, but also as pore-occupying hydrate in the coarser-grained layers of interbedded sand and fine-grained systems. A commonality across many of these occurrences is the presence of diatoms in the fine-grained sediment. Here we tested fine-grained sediment (median grain size <12.5 μm) associated with hydrate occurrences at four UBGH2 sites (UBGH2-2-2, UBGH2-3, UBGH2-6 and UBGH2-11) to investigate potential impacts of diatoms on efforts to extract methane from hydrate, or to tap hydrocarbon reservoirs beneath hydrate-bearing sediment. Two key considerations are: the extent to which diatoms control sediment mechanical properties, and the extent to which pore-water freshening, which occurs as gas hydrate breaks down during resource extraction, alters the diatom control on sediment mechanical properties. We conducted experiments to measure sediment index properties, sedimentation behavior and compressibility to address these considerations. We relied on scanning electron microscope (SEM) imagery and X-ray powder diffraction (XRD) to characterize the sediment mineralogy. Our high-level findings are that at the ∼20–45% (by volume) diatom concentrations observed at these UBGH2 sites, sediment compressibility increases with diatom content, but diatoms only appear to increase porosity and permeability at the highest diatom concentration (∼45%). Our measurements suggest in situ compression indices of 0.35–0.55 and permeabilities on the order of 0.01milliDarcies (1 × 10−17 m2) can be anticipated at these sites. Importantly, these properties are not expected to vary significantly upon pore water freshening that accompanies gas hydrate dissociation during production.

Advanced Distributed Acoustic Sensing Vertical Seismic Profile Imaging of an Alaska North Slope Gas Hydrate Field

Advanced Distributed Acoustic Sensing Vertical Seismic Profile Imaging of an Alaska North Slope Gas Hydrate Field

Dissociation of gas hydrates by hydrocarbon migration and accumulation-derived slope failures: An example from the South China Sea

The mechanism of slope failure associated with overpressure that is caused by hydrocarbon migration and accumulation remains unclear. High-resolution seismic data and gas hydrate drilling data collected from the Shenhu gas hydrate field (site SH5) offer a valuable opportunity to study the relations between submarine slope failure and hydrocarbon accumulation and flow that is associated with a ∼2 km-diameter gas chimney developed beneath site SH5 where none gas hydrates had been recovered by drilling and sampling despite the presence of distinct bottom simulating reflectors (BSRs) and favorable gas hydrate indication. The mechanism of submarine slope failure resulted from buoyancy extrusion and seepage-derived deformation which were caused by overpressure from a ∼1100 m-high gas column in a gas chimney was studied via numerical simulation. The ∼9.55 MPa overpressure caused by hydrocarbons that migrated through the gas chimney and then accumulated beneath subsurface gas hydrate-bearing impermeable sediments. This may have resulted in a submarine slope failure, which disequilibrated the gas hydrate-bearing zone and completely decomposed the gas hydrate once precipitated at site SH5. Before the gas hydrate decomposition, the largely impermeable sediments overlying the gas chimney may have undergone a major upward deformation due to the buoyancy extrusion of the overpressure in the gas chimney, and slope failure was initiated from plastic strain of the sediments and reduced internal strength. Slope failure subsequently resulted in partial gas hydrate decomposition and sediment permeability increase. The pressurized gas in the gas chimney may have diffused into the overlying sediments controlled by seepage-derived deformation, causing an effective stress reduction at the base of the sediments and significant plastic deformation. This may have formed a new cycle of submarine slope failure and finally the total gas hydrate dissociation. The modeling results of buoyancy extrusion and seepage-derived deformation of the overpressure in the gas chimney would provide new understanding in the development of submarine slope failure and the link between slope failure and gas hydrate accumulation and dissociation.

Numerical evaluation on the effect of horizontal-well systems on the long-term gas hydrate production behavior at the second Shenhu test site

In 2019–2020, the second natural gas hydrate field trial was successfully performed in the Shenhu Area of the South China Sea by using a horizontal well, however, the long-term production performance is unclear and needs intensive surveys. In this work, a multilayered hydrate reservoir model was constructed to replicate the short-term test result on the basis of the field data obtained at this site for the first time. Then, the long-term gas hydrate production behaviors at this site by using the single-horizontal-well and dual-horizontal-well systems were investigated, and the production strategy of thermal stimulation was proposed to examine the effects of the injection parameters of the hot water on the enhanced gas recovery. From the analysis of the simulation results, it can be known that due to the extremely low permeabilities of the whole reservoir (2.38–6.8 mD), the 10-yr average gas production rates (7.71 × 102–2.88 × 103 m3/d) could only reach 1/10 of the level obtained in the second Shenhu field trial (2.87 × 104 m3/d), which indicated that none of the above methods were quite suitable for future commercial gas production at this site. Therefore, it is recommended that permeability enhancement should be implemented in advance to improve the reservoir permeability before the actual long-term gas production.

Application of resonant oscillatory systems for the seafloor gas hydrates development

The prospects for the gas recovery from bottom gas hydrates are studied, and the necessity for the formation of an innovation environment and practical steps for conducting industrial experiments are formulated. The promising methods of shielded development of seafloor gas hydrate deposits are analyzed and the technical problems of their improvement are revealed. The possibilities of using resonant oscillatory systems for the shielded development of bottom gas hydrates are studied, in particular, a Helmholtz flow-excited resonator. The expediency of using high-quality oscillations of the “rotator” type has been substantiated in order to facilitate controlled gas hydrates dissociation over large areas of a gas hydrate field and to counteract the formation of new gas hydrates in the fractures of hydraulic reservoir fracturing. A method has been developed of gas recovery from bottom methane hydrates using a resonator device, which significantly reduces the energy consumption for the gas hydrates dissociation and contributes to the technological processes control.

Influence of the initial CH4-hydrate system properties on CO2 capture kinetics

Recovering methane from natural gas hydrate deposits using carbon dioxide injection is currently of great environmental and energetic interest as it shows potential for producing an energy resource while mitigating CO2 emissions through CO2 sequestration. This work investigates the exchange kinetic between CH4 and CO2 (or CO2-N2(v)) in synthetic hydrates, with an emphasis on the impact of CH4 hydrate formation conditions (e.g. driving force Δp) on the subsequent exchange reactions. Different driving forces Δp are utilized and show that the exchange kinetic is improved by a factor of ~3 when the exchange is performed with low Δp CH4 hydrates, for which there is a higher relative amount of free H2O(liq) (277 K); the kinetic is further improved when stirring is applied. Isobaric CH4 hydrates exhibit a fast primary hydrate dissociation and CH4 release, followed by a slower exchange kinetic, possibly limited by solid-state exchange diffusion or secondary CO2-rich hydrate formation within the stability field of CH4 hydrates. Upon exposure to a mixed CO2-N2(v) gas stream, secondary hydrate production is governed by the effective Δp remaining after dissolution of the gas mixture, and results in an even slower exchange reaction rate. These results may help optimizing recovery processes in field trial experiments, where both hydrates and liquid water coexist, and aid in predicting the risk of geo-hazards induced by unstable secondary hydrate formation. Furthermore, the exchange kinetic dependencies highlighted here are important as they affect the overall energy efficiency and energy cost of CH4 recovery processes in gas hydrate field trials.

Report Outlines Knowledge Gained in Gas Hydrate Production Testing

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 29516, “Gas Hydrate Production Testing: Knowledge Gained,” by Timothy Scott Collett, SPE, US Geological Survey, prepared for the 2019 Offshore Technology Conference, Houston, 6-9 May. The paper has not been peer reviewed. Copyright 2019 Offshore Technology Conference. Reproduced by permission. Gas hydrates are an important potential source of unconventional natural gas. Significant progress has been made with regard to understanding geologic and engineering limitations of the ultimate energy potential of gas hydrate; however, more work is required. The complete paper reviews the results of gas hydrate engineering and production testing studies associated with northern Canada and Alaska. The results of the marine gas hydrate producing testing efforts in Japan’s Nankai Trough and in the South China Sea are also summarized. Mallik (Canada) The Mallik gas hydrate research site in northern Canada has been the focus of three important gas hydrate field tests (in 1998, 2002, and 2007-08). The Mallik 2L-38 gas hydrate research well (part of the 1998 testing project) was drilled to evaluate the geologic controls on the occurrence of gas hydrate and to acquire specialized core and well data needed to characterize reservoir properties. During the 2002 project, gas hydrate was produced for the first time by both depressurizing and heating the reservoir. Depressurization alone appeared to be the most-feasible method for producing gas hydrates. However, because of the limited nature and duration of the 2002 tests, it was determined that a longer duration test would be required, leading to the 2007-08 research program. A 12-m-thick sand-rich hydrate-bearing reservoir was tested at a down-hole flowing pressure of approximately 7.3 MPa. The fact that gas hydrates can be produced by depressurization techniques was demonstrated. The winter 2006 operations included a 6-day depressurization flow, which was able to establish a sustained and stable gas flow rate averaging approximately 3000 m3/d. The total volume of gas and water produced over the duration of the test was approximately 13 000 and 100 m3, respectively. Alaska North Slope (US) The occurrence of gas hydrate on the Alaska North Slope is associated closely with well-characterized petroleum systems. The Mount Elbert gas hydrate test well, in 2007, showed a mobile water phase within hydrate-bearing reservoirs even at very high gas hydrate saturations. The recognition of the presence of a mobile water phase within gas hydrate reservoirs was an important development in that it provided the means, or pathway, to draw the pressure down on hydrate-bearing reservoirs. The PBU L-Pad area was identified as the optimal site for the subsequent Iġnik Sikumi gas hydrate production test.

Learning features from georeferenced seafloor imagery with location guided autoencoders

AbstractAlthough modern machine learning has the potential to greatly speed up the interpretation of imagery, the varied nature of the seabed and limited availability of expert annotations form barriers to its widespread use in seafloor mapping applications. This motivates research into unsupervised methods that function without large databases of human annotations. This paper develops an unsupervised feature learning method for georeferenced seafloor visual imagery that considers patterns both within the footprint of a single image frame and broader scale spatial characteristics. Features within images are learnt using an autoencoder developed based on the AlexNet deep convolutional neural network. Features larger than each image frame are learnt using a novel loss function that regularises autoencoder training using the Kullback–Leibler divergence function to loosely assume that images captured within a close distance of each other look more similar than those that are far away. The method is used to semantically interpret images taken by an autonomous underwater vehicle at the Southern Hydrates Ridge, an active gas hydrate field and site of a seafloor cabled observatory at a depth of 780 m. The method's performance when applied to clustering and content‐based image retrieval is assessed against a ground truth consisting of more than 18,000 human annotations. The study shows that the location based loss function increases the rate of information retrieval by a factor of two for seafloor mapping applications. The effects of physics‐based colour correction and image rescaling are also investigated, showing that the improved consistency of spatial information achieved by rescaling is beneficial for recognising artificial objects such as cables and infrastructures, but is less effective for natural objects that have greater dimensional variability.

Techno-economic viability studies on methane gas production from gas hydrates reservoir in the Krishna-Godavari basin, east coast of India

Gas hydrates are considered as a strategic unconventional clean hydrocarbon resource. This paper analyses the techno-economic viability of the methane gas production from the fracture-dominated gas hydrate reservoir in the Krishna-Godavari basin, east coast of India based on multi-well configurations. The analysis is done using the gas hydrate field depressurization-based production numerical simulator NIOT-IndHyd 1.1 and the gas hydrate field development return-of-investment cost model with reservoir petro-physical properties and India's current natural gas import price as inputs. The results indicate that reservoirs with post-dissociation permeability (PoDP) of >200mD with hydrate saturations >75% or higher PoDP are economic production targets for the present Indian natural gas import price of US$ 4.66/MMBtu. The payback period for multi-well configurations with a floating production unit for various reservoir post dissociation permeabilities are also presented.

Estimation of Methane Recovery Efficiency from Methane Hydrate by the N2–CO2 Gas Mixture Injection Method

Methane hydrate (MH) is the best-known unconventional energy resource and has begun to open its promising future, especially for Japan. In 2017, the second offshore gas hydrate field test was condu...

Endolithic Microbial Habitats Hosted in Carbonate Nodules Currently Forming within Sediment at a High Methane Flux Site in the Sea of Japan

Concretionary carbonates in deep-sea methane seep fields are formed as a result of microbial methane degradation, called anaerobic oxidation of methane (AOM). Recently, active microorganisms, including anaerobic methanotrophic archaea, were discovered from methane seep-associated carbonate outcroppings on the seafloor. However sedimentary buried carbonate nodules are a hitherto unknown microbial habitat. In this study, we investigated the microbial community structures in two carbonate nodules collected from a high methane flux site in a gas hydrate field off the Oki islands in the Sea of Japan. The nodules were formed around sulfate-methane interfaces (SMI) corresponding to 0.7 and 2.2 m below the seafloor. Based on a geochemical analysis, light carbon isotopic values ranging from −54.91‰ to −37.32‰ were found from the nodules collected at the shallow SMI depth, which were attributed to the high contributions of AOM-induced carbonate precipitation. Signatures of methanotrophic archaeal populations within the sedimentary buried nodule were detected based on microbial community composition analyses and quantitative real-time PCR targeted 16S rRNA, and functional genes for AOM. These results suggest that the buried carbonate nodule currently develops AOM-related microbial communities, and grows depending on the continued AOM under high methane flux conditions.

Long-term, continuous OsmoSampler results for interstitial waters from an active gas venting site at a shallow gas hydrate field, Umitaka Spur, eastern margin of the Japan Sea

Highly active gas venting and outcrops of gas hydrates were recently found at the Umitaka Spur, on the eastern margin of the Japan Sea, through seafloor observations using a remotely operated vehicle (ROV). This was followed by sampling by using conventional coring techniques. In this study, we deployed a long-term osmotic fluid sampling system (OsmoSampler) to record geochemical changes in the shallow sedimentary environment over time. The OsmoSampler collected interstitial water at 30 cm below seafloor (cmbsf), providing us with a continuous daily record of the concentrations of SO42−, Cl−, CH4, and C2H6 dissolved in interstitial waters over one year. General mean concentrations of SO42− and Cl− repeatedly showed synchronous increases and decreases over both long-term (i.e. dozens of days) and short-term (i.e. 3–5 days) periods. Such fluctuations relative to background seawater concentrations were likely caused by saline and fresh water generation due to gas hydrate formation and dissolution. The CH4 concentration was significantly higher (>1 mM) during large fluctuations in SO42− and Cl− over the first 3 months, which was attributable to gas-venting activity. This high venting activity of CH4 could have promoted the rapid, large-scale formation of gas hydrate. The CH4 concentration decreased gradually after the first 3 months, and was accompanied by a period of relatively low SO42− and Cl− concentrations due to the predominance of gas hydrate dissolution around the sampling site. In later months, the C2H6 concentration approached ∼1 μM and was accompanied by occasional, positive CH4 spikes, reflecting the release of trapped gases associated with the dissolution of hydrates. These processes are essentially controlled by the fluctuations in gas concentrations along the gas migration path, and are well-characterized by shallow interstitial water geochemistry.

Techno-economic forecasting of a hypothetical gas hydrate field in the offshore of India

Abstract The National Gas Hydrate Program 01 Expedition (2006) and the National Gas Hydrate Program 02 Expedition (2015) have established the presence of large deposits of gas hydrates in deep-water areas offshore India. This paper presents the results of a techno-economic study carried out for the development of a hypothetical gas hydrate field in the Krishna-Godavari (KG) Basin located along the eastern margin of India. Standard industry approaches have been used to carry out capital cost and operational cost estimates. Based on initial reservoir simulation modelling results, three cases have been considered to encompass the possible range of reservoir production responses. In the first case, 18 MMSCMD of gas is envisaged to be produced from 120 wells for a production period of 10 years. In the second case, 12 MMSCMD of gas is envisaged to be produced from the 120 wells for 16 years. In the third case, 6 MMSCMD of gas is envisaged to be produced from the 120 wells for 30 years. The production rates assumed in Case 3 best represents what is believed to be the most reasonable production rates as modeled for a gas hydrate accumulation (NGHP-02 Area B; Site NGHP-02-16) drilled during NGHP-02. For Case 1, an initial determination is that field development is economically viable for prevailing gas price of USD 7.67/MMBTU with NPV of 1921 MMUSD and IRR of 27.87% with a cost of production of USD 4.74/MMBTU. For Case 2, the study indicates that field development is viable with NPV of USD 986 MMUSD and IRR of 20.27% and cost of production of USD 5.8/MMBTU. For Case 3, the cost of production is USD 9/MMBTU. No production data is available for the gas hydrate accumulations discovered during NGHP-02 in the offshore of India; therefore, these techno-economic results generated in this study can only be validated after matching the results from future pilot production testing under actual field conditions.

Capillary effects on phase behavior of liquid and gaseous propane and dynamics of hydrate formation and dissociation in porous media

Using a precision adiabatic calorimetry method the phase behavior of liquid and gaseous propane with water in bulk as well as in dry and water saturated porous media have been studied in the temperature range from 240 to 350 K and the pressure range from 0.1 to 12 MPa. Quartz powder with a grain size from 25 to 38 mk as a porous medium was used. Water saturation of the porous medium was about 0.247 ± 0.001 of porous volume. From thermodynamic point of view such water saturation of the porous volume is sufficient to consider the pore water phase practically as a bulk phase. A composite porous medium is formed from the quartz powder grains covered by a water film. In fact, the water film is a mechanical continuation of the quartz powder grains. The water film forms a configuration (a curvature) of the porous space as well predetermines a surface wettability of the composite porous medium. We study capillary effect in composite porous media due to capillary condensation and capillary evaporation of propane, both on a lyophilic surface and on a lyophobic surface of water film. Based on the experimental data of specific heat and temperature derivative of pressure at constant volume, the phase diagrams of propane in bulk and in water saturated and dry quartz powder have been constructed (including the gas hydrate field of phase diagram).

Evaluation of gas production potential from gas hydrate deposits in National Petroleum Reserve Alaska using numerical simulations

An evaluation of the gas production potential of Sunlight Peak gas hydrate accumulation in the eastern portion of the National Petroleum Reserve Alaska (NPRA) of Alaska North Slope (ANS) is conducted using numerical simulations, as part of the U.S. Geological Survey (USGS) gas hydrate Life Cycle Assessment program. A field scale reservoir model for Sunlight Peak is developed using Advanced Processes & Thermal Reservoir Simulator (STARS) that approximates the production design and response of this gas hydrate field. The reservoir characterization is based on available structural maps and the seismic-derived hydrate saturation map of the study region. A 3D reservoir model, with heterogeneous distribution of the reservoir properties (such as porosity, permeability and vertical hydrate saturation), is developed by correlating the data from the Mount Elbert well logs. Production simulations showed that the Sunlight Peak prospect has the potential of producing 1.53 × 109 ST m3 of gas in 30 years by depressurization with a peak production rate of around 19.4 × 104 ST m3/day through a single horizontal well. To determine the effect of uncertainty in reservoir properties on the gas production, an uncertainty analysis is carried out. It is observed that for the range of data considered, the overall cumulative production from the Sunlight Peak will always be within the range of ±4.6% error from the overall mean value of 1.43 × 109 ST m3. A sensitivity analysis study showed that the proximity of the reservoir from the base of permafrost and the base of hydrate stability zone (BHSZ) has significant effect on gas production rates. The gas production rates decrease with the increase in the depth of the permafrost and the depth of BHSZ. From the overall analysis of the results it is concluded that Sunlight Peak gas hydrate accumulation behaves differently than other Class III reservoirs (Class III reservoirs are composed of a single layer of hydrate with no underlying zone of mobile fluids) due to its smaller thickness and high angle of dip.