bluuebunny/crossref_metadata_2025_split huggingface dataset:
Challenges and Opportunities of Gas Hydrate Production in China
Authors: Lau Hon Chung , Zhang Ming , Wang Jinjie , Pan Lin 
Published: March 2018

Gas hydrate has been found both in the permafrost and deep ocean in China. However, due to easier access, much lower well cost and proximity to existing gas pipelines, gas hydrate in the permafrost is more attractive for commercial development. In this paper we examine the published data on gas hydrate exploration in various Chinese permafrosts, identify the key technical challenges and suggest directions for future study.
Our study has identified Qilian Mountain Permafrost, Mohe Basin and Qinghai-Tibetan Plateau as the three permafrosts with highest potential for gas hydrate development. Of the three, only Qilian has confirmed occurrence of gas hydrate by coring. From the perspective of field operations, Qilian ranks highest in potential for development due to its proven hydrate occurrence, thickness of hydrate bearing layer and proximity to existing gas pipelines. Mohe ranks second due to its benign operating conditions. However, it lacks existing gas pipelines. Qinghai-Tibetan Plateau ranks third due to its high elevation which limits access and lack of oilfield infrastructure.
We found that the key subsurface uncertainty is the gas hydrate saturation. There is little information on it for all three permafrosts. Other subsurface uncertainties include the thickness of the permafrost, geothermal gradient beneath the permafrost, porosity, gas hydrate composition and permeability of the hydrate-bearing layer. Future research needs to determine these reservoir properties accurately.
Examination of core samples and logs from Qilian shows that gas hydrate distribution is discontinuous both vertically and areally. Therefore, a better way to quantify the uneven hydrate distribution in the reservoir is needed for reservoir engineering calculations.
Current estimates of well production rate by reservoir simulation are sub-commerical and probably due to the assumption of pure methane hydrate which limits the thickness of the gas hydrate stability zone. Also, the assumption of using horizontal wells for hydrate production may be optimistic due to shallow depths and the discontinuous nature of hydrate distribution. Consequently, new recovery methods besides depressurization and thermal stimulation will be needed to increase the well production rate.
Furthermore, we have identified a number of similarities in production engineering aspects of gas production from hydrate and coalbed methane (CBM) wells. Common challenges include reservoir depressurization by water production, solids production, need for artificial lift and difficulty in drilling long horizontal wells in shallow reservoirs. Therefore, some best practices from CBM production, such as pad drilling, artificial lift and water treatment methods, may be usable for gas hydrate production.
Hydrodynamic Interactions of Tank and Barge System for Modular Floating Oil Storage Tank Facility
Authors: Wan Ling , Magee Allan Ross , Zhang Chi , Jin Jingzhe , Han Mengmeng , Ang Kok Keng , Hellan Øyvind 
Published: March 2018

Abstract
A modular floating concept for oil storage is proposed. The concept, which is advantageous for space-constrained locations, is composed of several modular floating tanks and barges. The floating multi-body hydrodynamic interaction of barges are studied in this paper. In the analysis, a single barge and then two-barge system are firstly analyzed to investigate the hydrodynamic interaction effect. More bodies are involved in the subsequent investigation. This study provides physical principles for different basic scenarios, and practical insights into how the hydrodynamic interaction problem affect the multi-body floating system.
Investigation into the Performance and Safety of Alternative Refrigerants to Ammonia for Integrated OTEC Application
Authors: Lee C. J. , Lim F. H. , Lim J. A. , Osman Shariffah Mastura Noor , Hamid Nurul Shakira , MdNor MohdAdzwan 
Published: March 2018

Abstract
Ocean Thermal Energy Conversion (OTEC) has garnered international interest as a clean and sustainable source of secondary power generation, without impacting the environment and regardless of seasonal weather conditions, for offshore Oil & Gas (O&G) processing facilities. This is considering the suitability of waste heat extraction from existing offshore deepwater Oil & Gas platforms as a complementary application for integrated OTEC modules (hereafter abbreviated as i-OTEC). Such an application is possible with the availability of cold seawater drawn from extended seawater lift caissons or deepwater intake risers. This study investigates, in detail, the various refrigerants that are feasible alternatives to Ammonia (NH3) for a 1MWe i-OTEC scheme.
Anhydrous NH3 or R717 was initially selected as the refrigerant for the aforementioned i-OTEC scheme which is modelled based on an Organic Rankine Cycle (ORC). It is widely accepted that R717 is the ideal refrigerant for this application due to R717's high enthalpy change during expansion. Although R717 is classified toxic, R717 emissions generally do not create environmental problems, and is detrimental to health only upon presence of R717 at a Short Term Exposure Limit (STEL) of 35ppm. For comparison purposes, other alternative refrigerants were also studied; focusing particularly the risks associated with the refrigerants including toxicity, flammability, asphyxiation, reactivity and physical hazards. Hence, the selection of the refrigerant was a major factor in the design as it provides the basis for further investigation. Shortlisted alternatives, which include R1234yf, R410a, R134a, R290 and R32, were additionally assessed on multiple factors including expected enthalpy gain from the Rankine cycle, circulation flowrate, equipment sizing, hazard classification of refrigerants, compliance to international/local exposure standards, handling and storage of refrigerants.
It is identified that the aforementioned refrigerants are possible alternatives to R717 - but with some drawbacks from a thermodynamic performance perspective, and the fact that some of these refrigerants would be rendered obsolete in various industries. Consideration of the next generation of refrigerants must balance out factors such as public awareness, manufacturers availability, safety aspects and environmental concerns. The latest refrigerant with minimal environmental impact is R1234yf and it has been slowly accepted in the HVAC and motor industry.
Additionally, the turboexpander-generator shaft sealing was identified as the major source of refrigerant emissions during normal operation. Hence, various shaft sealing solutions were also scrutinized to assess the viability of utilizing R717 as a refrigerant whilst still fulfilling safety and emission requirements.
Enhanced Gas Recovery from Water Saturated Hydrate Bearing Sediments Using Horizontal Wellbore
Authors: Rong Chong Zheng , Yin Zhenyuan , Cheong Khoo Boo , Linga Praveen 
Published: March 2018

AbstractNatural gas hydrate is regarded as a potential energy resource in the future. Although it is well known that hydrate dissociation produces both gas and water, it is still unclear how gas and water are produced from hydrate bearing sediment in response to different production strategies. While a large body of literature have focused on elucidating the effect of production conditions (e.g. pressure, temperature) on the dissociation behaviour from hydrate reservoirs, limited effort has been paid in investigating how gas and water production can be simultaneously controlled through process design (e.g. the incorporation of wellbore, wellbore design).In this study, the effect of a single horizontal wellbore on gas and water production from water saturated hydrate bearing sediments of 40% hydrate saturation (SH) was evaluated by a comparison with the base case (without wellbore) in a 980 mL crystallizer at a bottom hole pressure (BHP) of 3.5 MPa. Distinctive production behaviour, in terms of temperature, gas and water production kinetics, was observed in each production configuration. We have demonstrated an improvement of ~ 15% in gas production through the addition of horizontal wellbore in the current system. Even more so, water production was found to be reduced significantly (~ 50%) through the incorporation of horizontal wellbore. This finding revealed opportunities in future research to develop technology that enable simultaneouos enhancement of gas production and mitigation of water production during hydrate recovery.
Effect of Polyethylene Glycol Aqueous Solution on Methane Production from an Artificial Hydrate Reservoir
Authors: Mech Deepjyoti , Nair Vishnu Chandrasekharan , Kumar Ganesh , Sangwai Jitendra S 
Published: March 2018

Abstract
Natural gas hydrates have gained a huge attention as a potential future energy source. Reserches and pilot operations on methane recovery from hydrate reservoirs are going on worldwide. In the present work, an artificial hydrate reservoir has been developed in lab scale using silica sand of 0.16 mm particle size, distilled water and methane gas inside a high-pressure reactor. The effectiveness of polyethylene glycol (PEG) as an inhibitor for the dissociation of natural gas hydrate has been investigated. A porous sand bed of 70% water saturation has been prepared inside a high-pressure reactor and then charged with methane gas at 8 MPa. After the hydrate formation in the porous bed, for dissociation of the hydrate reservoir, PEG aqueous solution has been injected into the hydrate reservoir using a syringe pump. The pressure of the reactor has been maintained in between the equilibrium pressure of pure methane hydrate and methane hydrate in the presence of PEG using a back-pressure regulator. The injection of PEG aqueous solution has been performed at 0.4 mass fraction for methane recovery from the artificial hydrate reservoir. PEG-200 aqueous solution has shown a methane gas production ratio of 47.38%. This work provides a practical approach to use polymer as an effective inhibitor for the production of methane from hydrate reservoir especially for low temperature and permafrost hydrate-bearing zones. This is the first work that uses an environmental friendly polymer as inhibitor for the hydrate dissociation for methane production from a natural gas hydrate. It has been observed that PEG performs well as a thermodynamic and kinetic inhibitor. In addition, PEG is having −65oC freezing point, which is more than a commercial inhibitor, ethylene glycol (-13.4oC), therefore using PEG as an inhibitor is more beneficial for the production of gas from a low-temperature hydrate reservoirs.
Risk-Based Flow Assurance Design for Natural Gas Hydrate Production Systems
Authors: Norris Bruce W. E. , Charlton Thomas B. , Johns Michael L. , May Eric F. , Aman Zachary M. 
Published: March 2018

Abstract
Transport in subsea gas gathering networks of hydrocarbons liberated from natural hydrate deposits poses many of the same risks as faced in more traditional hydrocarbon production. There is an inherent need to ensure that these fluids do not recombine into hydrates within the flow network, a familiar problem in flow assurance. This paper describes a risk based approach to assessing hydrate formation in the transport flowline of a produced hydrate deposit. The bathymetry is typical of those found off the Australian coast, with fluid properties as expected for a methane rich natural hydrate deposit. To fully assess the ‘risk’ of hydrate formation, probabilistic analysis based on Monte-Carlo simulation of the blowdown pressure and nucleation temperature are performed. This is coupled with targeted transient analysis of the severity of hydrate formation using a new plugin for OLGA®, which focuses on the mechanics of hydrate formation in gas dominant systems.
Multi Functional Pipeline Systems
Authors: Critsinelis Antonio , Mebarkia Sid , Lundeen Kale , Kalia Akshay , Skowronek Tyler , O'Neill Eoghan , Zeid Hosam Abu 
Published: March 2018

Abstract
Long-distance tiebacks are becoming more prevalent for subsea projects and present many unique challenges for successful operation. Flow assurance challenges arising from different operational regimes as well a high capital cost for enabling reliable production pose a unique challenge for long-distance tiebacks. A potential mitigation is the use of a pipe-in-pipe system for insulating purposes.
The multifunctional pipeline system (MFPS) aims to provide further functionality and flexibility to the pipeline system by utilizing the annulus of the pipe-in-pipe system as an additional transportation line thus, providing the flexibility and added functionality to the pipe-in-pipe system to increase operational flexibility, reduce capex and opex, and improve system availability to drive capital efficiency. The MFPS station can also be used to detect a plug location, monitor pressure on both sides of a plug, circulate hot fluid in the annulus and bypass the affected section. This technology was developed in joint collaboration with Chevron and Schlumberger.
This paper will highlight the overall functionality of the MFPS, the concepts that were investigated during the development of the MFPS, and the benefits that each unique concept provides to the overall field architecture.
Numerical Modelling of Methane Hydrate Dissociation in Sandy Porous Media by Depressurization with a Parametric Study
Authors: Yin Zhenyuan , Moridis George , Tan Hoon Kiang , Linga Praveen 
Published: March 2018

Abstract
Due to its increasing abundance, cleaner and lower emissions upon combustion, natural gas (NG) has been considered as the best transition fuel away from coal and oil to a carbon-constrained world. Methane gas is the major component in NG accounting for 70-90%, and is also the major constituent found in natural gas hydrates (NGHs). The amount of CH4 preserved in NGHs is vast and estimated to be 20,000 trillion cubic meter (TCM) worldwide. This outweighs the proved NG reserve on earth, which is 865.4 TCM, and doubles the combined reserve of all fossil fuels. Thus, NGHs have been considered as a potential future energy source. Extensive geological surveys and drilling programs have been carried out during the past two decades at various countries (Canada, USA, Japan, S. Korea, India, China, etc.) to identify the location of these NGH reservoirs, to quantify the amount of gas deposited and to recover hydrate cores to analyze their thermophysical and geomechanical properties. Extensive research have also been carried out in laboratories to synthesis gas hydrate mimicking marine and permafrost conditions, and to study their fundamental behavior of formation and dissociation. In this study, we numerically analyzed an experiment of methane hydrate bearing sediment (P = 6.2 MPa) with hydrate saturation SH = 40% dissociation process induced by depressurization (P = 4 MPa) in a 1.0 L reactor with the production of water and gas. The simulation-predicted cumulative gas production shows an excellent agreement with the experimental measurement. In addition, from the evolution of phase saturation over time, it is revealed that hydrate dissociates from outer boundary to inner core. In addition, methane gas migrates to the reactor outer boundary first and accumulates to the upper section of the reactor mainly due to buoyance effect, while water drains down to the bottom of the reactor due to gravity. The parametric study on the fulids and thermal transport parameters (absolute permeability, k and HBS composite thermal conductivity, kθ) and the kinetic parameter (K°) concluded that the gas production process is predominated controlled by thermal and kinetic reaction paramters, while flow paramters does not play a significant role in the current smallscale reactor.
An Integrated Multi-Scale Numerical Simulation of Transient Gas Flow in Shale Matrix
Authors: Zhan Jie , Soo Eric , Fogwill Allan , Cheng Shiqing , Cai Hua , He Ruijian , Chen Zhangxin 
Published: March 2018

AbstractThe gas flow in shale matrix is of great research interest for optimizing shale gas development. Due to a nano-scale pore radius, the gas flow in the shale matrix may fall in flow regimes which include viscous flow, slip flow and Knudsen diffusion. On top of that, gas adsorption/desorption and stress-sensitivity are some other important phenomena in shale. In this paper, we introduce an integrated multi-scale numerical simulation scheme to depict the above phenomena which is crucial for the shale gas development.Instead of Darcy's equation, we implement the apparent permeability in the reservoir-scale continuity equation to depict the gas flow (viscous flow, slip flow and Knudsen diffusion) in shale matrix. A Langmuir adsorption/desorption term is included in the reservoir-scale continuity equation as a generation term. To ensure the real-time desorption and adsorption equilibrium with gas production, an iterative mass balance check of pore wall surfaces (pore scale) is introduced. At each time step, the pore-scale and reservoir-scale mass balance should be satisfied simultaneously in each grid block. On top of that, the lab data of a Bakken reservoir which provides a relationship between a matrix pore radius reduction and the effective stress is integrated into the two-way coupling geomechanical process to simulate a stresssensitive shale formation.This methodology examines the influence of each mechanism for the shale gas flow in the matrix. Instead of conventional pressure-independent Darcy permeability, the apparent permeability increases with the development of a shale gas reservoir. With the gas adsorption/desorption, the reservoir pressure is maintained via the supply of released gas from nano-scale pore wall surfaces. With the consideration of geomechanics, the apparent permeability is decreased due to the compaction of nano-scale pore radii, which leads to the maintenance of reservoir pressure. Due to the difference of compaction magnitude for each grid block, geomechanics create additional heterogeneity for a nano-pore network in shale matrix, which we should pay more attention to.A novel integrated multi-scale methodology is introduced to examine the crucial phenomena in the shale matrix, which simultaneously takes into account the influence of flow regimes, gas adsorption/desorption and stress-sensitivity. An effective way is provided to quantify the above effects for the transient gas flow in shale matrix.
Big Data Analytics for Micro-Seismic Monitoring
Authors: Joshi P. , Thapliyal R. , Chittambakkam A. A. , Ghosh R. , Bhowmick S. , Khan S. N. 
Published: March 2018

Abstract
Big data technology is applied to analyze massive micro-seismic data set, which incorporates previously over-looked data set. This, in turn, will give redundant fracture modelling in stages and exact fracture propagation map in real time. Micro-seismic is pivotal to the success of Hydraulic Fracturing activity. However, with the advent of advanced geophones, the massive dataset requires a different analytical point of view, currently absent in conventional database processing and algorithms. HADOOP equips with the necessary tools for better and advanced real-time processing and analysis.
Various Algorithms are developed to show comprehensive fracture operation analysis. Previous job failures are used to predict future anomalies, hence enhancing success ratio. The holistic dataset for the reservoir (Exploration, Drilling, and Production) are considered to synchronize the reservoir information. For example, drilling data (ROP, drillability, WOB etc.) is analyzed to predict the type of formation (like Brittle or Ductile), poroelastic constant, elasticity etc. Comprehensive analysis of fracture propagation would consider all the parameters associated not just conventional ones.
The dataset is stored in Hadoop and called upon whenever needed. The massive amount of dataset is not being processed in conventional databases but can be integrated using Hadoop. The analytical results provided from Hadoop stands out from conventional formulae based software. The visualization of results keeps the minimum scope of error contradicting with the currently used ones. In current ones, many data trends and parameters are left out which are not used in formulae. Those patterns are visually shown and incorporated into the analysis, causing better mapping of fractures. Not only just complementing current analysis, Big Data provides the scope of comprehensive analysis from start to end. When 3D seismic appeared, it was a radical change. It not only showed 2D maps were of low resolution, rather those were rendered misleading. The Hadoop analytics is providing a unique perspective, leaving some mismatches, which are needed and to be seriously considered for future planning.
The resulting model does not use conventional formulae, hence not limited to consider the real-time data. Rather field data (associated with noise) is analyzed using algorithms, generating trends from noises and deviations. The conventional software misses massive relevant data, which apparently cannot be incorporated into formulae. That inability is being met with Big Data analytics. Conventional database management is unable to handle so much data, which are being taken care off by Hadoop platform.
Development of Supercritical CO2 Mineral Carbonation Technology for High CO2 Fields Development
Authors: Noh M Ghaddaffi M , Onn M Syazwan , Berahim N Hafizah , Mumtaz Hazratul 
Published: March 2018

Abstract
Development of ultra high CO2 field in Malaysia is the next frontier as far as contaminated green field development is concerned. Large hydrocarbon reserve is a major driver to mature technology to support the development of contaminated fields. However, managing the contaminant CO2 is still a major drawback as far as technology is concerned. Base case consideration for CO2 emission mitigation for offshore high CO2 gas fields had always been geological injection even though it deteriorates the overall field economics to a point which may prove to be prohibitive for some field development cases. An alternative method to mitigate CO2 would be the conversion of CO2 to higher value products which provides return in the form of additional revenue or profit. The monetory income from the conversion of CO2 can be utilized to either fully or partly offset the high cost of CO2 injection. This paper attempts to summarise the experience based on feasibility study, technical consideration and lesson learnt by PETRONAS to mitigate the CO2 emissions from the development of such high CO2 gas fields. The summary is done in the context of selecting the suitable CO2 mitigation technology, scale of conversion, maturing the technology and economic consideration as an integral part of the field development.