China Energy Reserve and Chemicals Group is exploring the possibility of importing LNG from the US via ISO containers loaded from the West Coast. Japan is bringing its nuclear reactors back on line following the suspension of operations at all reactors after the 2011 Fukushima accident. As the reactors return to full operation, the increase in nuclear generation is likely to displace generation from fossil sources, in particular natural gas.
Freeport marks the sixth major LNG export facility to start operations in the US. Commercial deliveries are expected to begin in September, with Osaka Gas and JERA taking half of the Train 1’s offtake capacity. The US EIA reports that natural gas deliveries producting LNG for export reached 6.0 Bcf/D in July. Deliveries to LNG export facilities have been the fastest growing among all natural gas consumption sectors this year. The launch will make Shenzhen Gas the second Chinese city gas distributor backed by a local government to own an LNG import facility, following Shenergy Group’s Shanghai import terminal.
Freeport LNG became the sixth major US liquefaction facility to start operations, as McDermott International, along with its partners Chiyoda International Corporation and Zachry Group, confirmed the beginning of LNG production from Train 1. Freeport LNG Trains 2 and 3 remain on track to meet their previously announced schedules, with initial production from Train 2 scheduled for the fourth quarter of 2019 and Train 3 scheduled to start up in the first quarter of 2020. A proposed fourth train is expected to add more than 5 mtpa of LNG production to the project, increasing the total export capacity of the facility to more than 20 mtpa, but Freeport has not sold enough capacity to finance construction. Production from Train 1 started on 12 August and has continued since. Freeport said that it expects to begin long-term contractual deliveries next month once commissioning cargoes are exported. Osaka Gas and JERA, a joint venture between Tokyo Electric Power Company Holdings and Chubu Electric Power Company, will each take half of the first train’s total contracted capacity of approximately 4.64 mtpa after commercial operation begins later this year.
There are currently two types of relative permeability models that are used to model gas production from hydrate-bearing sediments: fully empirical parameter-fitting models [such as the University of Tokyo model (Masuda et al. 1997) and the Brooks and Corey model (Brooks and Corey 1964)] and partially empirical models [such as the Kozeny and Carman model (Wyllie and Gardner 1958) and capillary-tube-based models that assume only a single phase]. This study proposes an analytical model to estimate relative permeability of gas and water in a hydrate-bearing porous medium without curve fitting or use of any empirical parameters. The model is derived by conserving the momentum balance with the steady-state form of the Navier-Stokes equation for gas/water flow in a hydrate-bearing porous medium. The model is validated against a number of laboratory studies and is shown to perform better than most empirical models over a full range of experimental data. The proposed model is an analytical function of rock properties (average pore size and shape, porosity, irreducible water saturation, and saturation of hydrate), fluid properties (gas/water saturations and viscosities), and the hydrate-growth pattern [pore filling (PF), wall coating (WC), and a combination of PF and WC]. The benefits of the proposed model include sensitivity analysis of relevant physical parameters on relative permeability and estimation of rock parameters (such as porosity, pore size, and residual water saturation) using inverse modeling. The model can also be used to estimate two-phase permeability in a permeable medium without hydrates.
The proposed model was used to analyze the effects of pore shapes, the hydrate-growth pattern, variable gas saturation, and wettability on relative permeability. The sensitivity results produced by the proposed model were verified using observations from other studies that investigated similar problems using either experiments or computationally expensive pore-scale simulations.
Yoneda, Jun (National Institute of Advanced Industrial Science and Technology) | Takiguchi, Akira (West Japan Engineering Consultants) | Ishibashi, Toshimasa (West Japan Engineering Consultants) | Yasui, Aya (West Japan Engineering Consultants) | Mori, Jiro (West Japan Engineering Consultants) | Kakumoto, Masayo (National Institute of Advanced Industrial Science and Technology) | Aoki, Kazuo (National Institute of Advanced Industrial Science and Technology) | Tenma, Norio (National Institute of Advanced Industrial Science and Technology)
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.
Investigation of the effectiveness of matrix stimulation treatments for removing drilling induced damage in Akita region in northern Japan is of interest due to the presence of large quantities of acid-sensitive minerals, such as analcime. Feasibility study of the sub-commercial field redevelopment in the Kita-Akita oil field, one of the satellite fields of main Yabase oil fields, which produced from 1957 to 1973, and were plugged and abandoned, were conducted. As a part of the studies, matrix acidizing laboratory experiments were performed. Conventional mud acids and formic-based organic mud acid systems cause significant permeability damage due to instability of analcime in these acids. This study focuses on the development of a treatment fluid that removes drilling-induced damage and is also compatible with the formation.
Petrology studies and core flow tests were used in conjunction with geochemical modeling to achieve this objective. A petrographic analysis on the untreated cores showed abundant tuffaceous pore-filling mineral phases, ranging from 12 to 20% in volume. Smectite clay and microcrystalline quartz are the major constituents as alteration products of volcanic glass. Analcime was present in significant quantities in all samples tested.
Six core flow tests were performed on formation cores to optimize the acid preflush and main acid stage. Permeability change due to the treatment fluids was recorded for the tests. Chemical analysis of the effluent was performed on three core flow tests. Core samples before and after acidization were characterized based on thin section, X-ray diffraction (XRD), scanning electron microscopy(SEM) and mineral mapping.
Core flow tests with a conventional retarded organic mud acid resulted in only a 75% retained permeability. The permeability damage by the retarded organic mud acid was surprising because it usually performs well in acid-sensitive formations. A chelant based retarded mud acid was tested next and resulted in minor formation damage. It can potentially be used in a field treatment as its high dissolving power is expected to more than compensate for the damage. The highest retained permeability was obtained with an acetic-HF acid system. It was successfully able to remove drilling-induced damage and was also compatible with the native mineralogy. Core flow tests were used to calibrate permeability-porosity relationship used in the geochemical simulator. The geochemical simulator was then used to predict field-level acid response.
The analytic methods presented are general enough to be of interest to sandstone acidizing studies where detailed analysis is needed for damage identification and removal. The fluids developed for this formation area good candidates for other formations where conventional acid systems have not performed well. This study also highlights close collaboration between an operator and service company to find a workable solution to a challenging stimulation requirement.
In order to sail 470 faster, authors consider the sailing performance of 470 from the various measured data and the simulated results of VPP (Velocity Prediction Program). This is a summary of TOBE-470 presented by the author.
The 470 (Four-Seventy) was designed in 1963 by the Frenchman Andre Cornu as a double-handed mono-hull planing dinghy. The name comes from the overall length of the boat in centimeters (470cm). The 470 is a World Sailing International Class has been an Olympic class since the 1976 games. In Japan, the 470 is used in university championships and in National Athletic meets. So, it is in the most popular dinghy race in Japan. An ideal crew weight of skipper and crew is 130kg, it is suitable for Japanese who are smaller than Europeans and Americans. This paper progresses the science of the sailing performance of the 470 with respect to aspects such as hull performance, sail performance, steady sailing performance and maneuvering performance.
Tokyo Gas received its first cargo produced at Dominion’s Cove Point LNG terminal in May 2018 via the LNG Sakura. Japan is bringing its nuclear reactors back on line following the suspension of operations at all reactors after the 2011 Fukushima accident. As the reactors return to full operation, the increase in nuclear generation is likely to displace generation from fossil sources, in particular natural gas. Because Japan imports all of its natural gas in the form of LNG, increased nuclear power production is likely to reduce Japanese imports of LNG in the electric power sector by as much as 10% in 2019. Japan suspended operations at all nuclear reactors for mandatory safety inspections and upgrades, leaving the country with no nuclear generation from September 2013 to August 2015.
Morita, Hiromitsu (National Institute of Advanced Industrial Science and Technology (AIST)) | Muraoka, Michihiro (National Institute of Advanced Industrial Science and Technology (AIST)) | Yamamoto, Yoshitaka (National Institute of Advanced Industrial Science and Technology (AIST))
This paper measures the thermophysical properties of natural methane hydrate (MH)-bearing sediments recovered from the Nankai Trough, Japan. The thermal conductivity, thermal diffusivity, and specific heat of the sample under vertical stress (VS) loading were measured by the hot-disk transient method. The thermal conductivity of the sediments increased with increasing VS. The specific heat and thermal diffusivity have a constant value independent of VS. After MH dissociation, the thermal conductivity and the specific heat dropped significantly, and the thermal diffusivity was increased. In addition, the thermal conductivity, specific heat, and thermal diffusivity were calculated by an estimation model.
Methane hydrate (MH) is expected to be developed as an unconventional natural gas source, replacing existing fossil fuels. MH is a crystalline solid in which cages of hydrogen-bonded water molecules enclose the methane gas molecules. MH is stable in a high-pressure/low-temperature environment. A large amount of MH is known to exist in permafrost on land and in sedimentary layers beneath the seabed (Sloan and Koh, 2007).
The collected seismic data for oil and gas exploration show a wide distribution of bottom-simulating reflections (BSRs) under the seafloor in the Nankai Trough region near the Japan Sea coast. BSRs indicate the lower limit of gas hydrate stability zone in a vertical profile. In 1999, the first Nankai Trough methane hydrate exploration well was drilled. In early 2004, the Japan Ministry of Economy, Trade, and Industry drilled a multiwell from Tokaioki to Kumano-nada (Tsuji et al., 2009). The core was recovered using a pressure-temperature core sampler, which maintained the in-situ condition of 16 excavation sites at water depths ranging from 720 to 2,030 m in the same year. Recovered core analysis confirmed that the MH-bearing sediments in the Nankai Trough area are pore-filling-type hydrates (Fujii, Nakamizu, et al., 2009; Fujii, Saeki, et al., 2009).
Shibayama, Atsushi (Central Research Institute of Electric Power Industry) | Miyagawa, Yoshinori (Central Research Institute of Electric Power Industry) | Kihara, Naoto (Central Research Institute of Electric Power Industry) | Kaida, Hideki (Central Research Institute of Electric Power Industry)
The damages of the gigantic tsunami that followed the 2011 Great East Japan Earthquake were confirmed on reinforced concrete (RC) structures (Nandasena et al., 2012). Moreover, the damages caused by the tsunami debris collision were confirmed in addition to the damages caused by only the tsunami. Therefore, it is important to clarify the response characteristics of the structure subjected to the tsunami wave force and collision force, and to establish a response evaluation method by numerical analysis. However, the response characteristics of RC structures subjected to two external forces with significantly different timings of actions--namely, wave pressure and collision forces--have not been clarified. Furthermore, to assess the responses of RC structures using numerical analysis, the two different types of superimposing external forces must be considered. However, the applicability of numerical analysis under such external force conditions has not been sufficiently verified. In this research, a large-scale debris collision experiment was first conducted to experimentally investigate the response of an RC vertical wall subjected to the wave pressure and debris collision forces. Next, a reproducibility analysis of the experiment was performed with nonlinear finite element analysis to examine the adaptability of the finite element analysis.