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Jia, Ying (Exploration and Production Research Institute, Sinopec) | Shi, Yunqing (Exploration and Production Research Institute, Sinopec) | Yan, Jin (Exploration and Production Research Institute, Sinopec)
Abstract Tight gas reservoirs are widely distributed in China, which occupies one-third of the total resources of natural gas. The typical development method is under primary depletion. However, the recovery of tight gas is only around 20%. It is necessary to explore a new technique to improve tight gas recovery. Injecting CO2 into tight gas reservoirs is a novel trial to enhance gas recovery. The objective of this work is to verify and evaluate the effect supercritical CO2 on enhancing gas recovery and analyze the feasibility of CO2 enhance gas recovery of tight gas reservoir. Taken DND tight sandstone gas reservoir in North China as an example, 34 wells of DK13 wellblock were chosen as CO2 Enhanced gas recovery pilot area with 10-year production history. Six injection scenarios were studied. Numerical simulation indicated that the recovery of the gas reservoir of DK13 well area was improved by 8-9.5 percent when CO2 content of producers reaches 10 percent. The annual CO2 Storage would be 62 million cubic meters (110 thousand tons) and the total CO2 storage would be around 800million cubic meters (1.5 million tons). After the environmental parameter evaluation of injectors and producers, the anticorrosion schemes were put forward and the feasibility evaluation and schemes of facilities were presented. The analysis results indicated that DK13 wellblock was suitable for CO2 enhanced gas recovery no matter geologic condition, injection & production technology and facilities. However, under the current economic conditions, DK13 wellblock was not suitable for CO2to enhance gas recovery. However, if gas price rise or low carbon strategy implement, the pilot test could be carried out. In brief, CO2 could be an attractive option to successfully displace natural gas and decrease CO2 emissions, which is a promising technology for reducing greenhouse gas emission and increasing the ultimate gas recovery of tight gas reservoirs. This economic analysis, along with reservoir simulation and laboratory studies that suggest the technical feasibility of CSEGR, demonstrates that CSEGR can be feasible and that a field pilot study of the process should be undertaken to test the concept further.
The Oil and Gas Climate Initiative (OGCI), the CEO-led enterprise formed to drive the industry response to climate change, has launched a new effort to unlock large-scale investment in carbon capture, use, and storage (CCUS) as a crucial tool to help achieve net zero emissions. The CCUS initiative is designed to help decarbonize multiple industrial hubs around the world. The goal of the initiative, according to OGCI, is to double the amount of CO2 that is currently being stored globally before 2030 while building a pipeline of potential future hubs to bring the fledgling CCUS industry to scale. To achieve this goal, OGCI says it will start by building on the work of many others to jointly put five emerging hubs into operation in the US, the UK, Norway, the Netherlands, and China. In parallel, OGCI announced it has launched a joint CCUS Acceleration Framework with the 11 countries supporting the Clean Energy Ministerial CCUS Initiative, a high-level global forum working to create a global, commercial CCUS industry at the scale needed to meet the Paris Climate Agreement goals.
Zhang, Zhuo (Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education / Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application) | Chen, Peng (Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education / Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application) | Song, Zhiyao (Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education / Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application) | Liu, Fengfu (Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education / Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application) | Guo, Fei (Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education / Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application) | Zhang, Dong (Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education / Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application)
ABSTRACT The FVCOM-based shallow water circulation model, was used to study the influence on surge by uncertainties in typhoon prediction. Typhoon Mangkhut,was used as a typical storm surge scenario to validate the model. A series of synthetic storm surge scenarios was developed based on the original Typhoon Mangkhut to investigate the characteristics of the behavior of surge around the Pearl River Estuary,.The main conclusions herein can enhance the learning about storm surge and possible inundation in the area. INTRODUCTION Storm surge is a major hazardous factor which causes the flooding damage, life loss and transport block in coastal and estuarine regions. Most surges in summer and autumn in China are caused by typhoon, developed from the tropical cyclone born in Western Pacific. From statistic data, these typhoons averagely cause 25 billion yuan every year in China (Liu, et al, 2018). The Pearl River Delta, located on the south coast of China and is one of the most developed economic zone in world, especially suffered vast economic loss in the past decade for its high occurrence of typhoon. With the global warming and the increment of sea level, the typhoon occurrence and the induced surge become increasingly frequent. During the period from 2008 to 2019, more than 50 typhoons approach and cause surge in Pearl River Estuary and nearshore waters, including super typhoons like Hagupit (2008), Rammasun (2014), Mujigae (2015) and Mangkhut (2018). Of these, Typhoon Mangkhut recently caused the most devastating damage and influenced nearly 3 million local residents. Consequently, there is a growing concern about accurate storm surge prediction and the subsequent hazard mitigation response, which must be based on a clear understanding of the factors that contribute to storm surge in the specific area. Many efforts have been carried out for numerical modeling and analysis of surges induced by typhoons and cyclones. Tide and surge usually occur simultaneously with the result that their superposition and interaction determine the high water level, which is referred as the basis for coastal engineering design and flood hazard assessment. A few early studies either separated the surge and tide, or neglected the effect of tide on surge. Through theoretical investigation, Proudman (1955) claimed that for a progressive wave, the height of a surge with its maximum occurring near to time of tidal high water was less than that of a surge with its maximum occurring near to the time of tidal low water. Prandle and Wolf (1978) analyzed the observation results in the Thames estuary with a numerical model and concluded that surges tend to reach a maximum on rising tide irrespective of the phase relationship between tide and surge in the open seas. Zhang et al. (2010) studied the oscillation of storm surge by the tide-surge interaction in shallow water of the Tanwan Strait and emphasized both roles of nonlinear bottom friction and the special geometry of the strait. Park and Suh (2012) found that the storm surge was in an inverse proportion to water depth and tide. These results provided useful insight into the processes with surge and tide propagating together.
Clean-burning hydrogen (H2) - and scenarios for a future economy powered by it - is big news at the moment. This is no surprise, given the current environment of low demand for oil, growing unease over greenhouse gas emissions, and projections that post-pandemic stimulus measures could do for hydrogen what stimulus measures after the 2008 financial crisis did for solar power. Oil and gas majors have spent tens of millions of dollars on pilot projects, as have other industrial giants. Germany, which has allocated $10 billion to its nascent hydrogen industry, is one of a growing number of governments whose spending to satisfy climate commitments while restarting their economies could provide a major funding kickstart. But for the moment, most analysts agree that the future for a hydrogen economy is still uncertain and that the biggest obstacles to scaling will be costs, technology scaleup, and policy. H2 101 - From Feedstock to Fuel Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all mass. Today approximately 3% of global energy consumption is used to produce hydrogen, at a rate of more than 110 million tons per year, according to BloombergNEF (BNEF). So, hydrogen production is already a large and thriving industry. Yet, according to the Hydrogen Council, only 0.002% of currently produced hydrogen is used as fuel. Some 90% is used for ammonia production, petroleum refining, and methanol production. DNV GL, in a recent report on hydrogen as an energy carrier, describes hydrogen as a unique zero-emission energy carrier that can be converted to electrical energy in a fuel cell two to three times more efficiently than in a combustion engine. Hydrogen as an energy carrier can exist in a variety of forms and can be converted from one form to another, while energy sources such as oil and gas are the original resource from which the energy carrier is produced. Hydrogen can be used as fuel for mobility and heating in buildings; to decarbonize industrial processes; and as price support and storage for excess electricity during periods when production output from renewables alone exceeds demand. BNEF reports in its Hydrogen Economy Outlook that deploying clean hydrogen in the coming decades could reduce up to 34% of global greenhouse gas emissions from fossil fuels and industry at manageable cost. Renewable hydrogen could be produced for $0.70 to $1.60/kg in most parts of the world before 2050 - the equivalent of gas priced at $6-$12/MMBtu, making it competitive with current natural gas prices in Brazil, China, India, Germany, and Scandinavia on an energy-equivalent basis.
Wang, Chunpeng (Petrochina Research Institute of Petroleum Exploration and Development) | Cui, Weixiang (Petrochina Research Institute of Petroleum Exploration and Development) | Zou, Honglan (Petrochina Research Institute of Petroleum Exploration and Development) | Wang, Chao (Petrochina Research Institute of Petroleum Exploration and Development) | Zhang, Xiwen (Petrochina Research Institute of Petroleum Exploration and Development)
Compared with hydraulic fracturing, CO2 waterless fracturing can an alternative technology for the unconventional resources, such as the tight oil resources and the tight gas resources. It is an environment-friendly fracturing technology. Liquid CO2 fluid can be more easily obtained, and it is safe and non-explosive. Under formation temperature, it has ultra-low interfacial tension in supercritical state, so it has strong penetration ability, which can penetrate into matrix of reservoir and communicate with reservoir deeply. At the same time, it can reduce the viscosity of crude oil. Therefore, it is a kind of ideal fracturing fluid. This technology is significant for clean and efficient development of low-permeability tight oil reservoirs, and worthy of broad application.
The technique is divided into three stages. The large-scale high-pressure injection of liquid CO2 after fracturing, fracturing, continue to inject CO2 throughput, through multiple rounds, cyclic injection, CO2 from the wellbore along the cracks gradually extended to the distal end, increase formation energy, the single well control range and improve the producing rate of the reserves, at the same time to dissolve crude oil extraction, oil viscosity decrease. The CO2 steam soak, enhanced oil recovery rate decreased gradually, while the enhanced oil recovery rate is lower than the economic limit, the implementation of CO2 refractured, further increase the transformation volume, continue to inject CO2 multi cycle throughput, the CO2 can be extended to the depths of the reservoir, and further improve the reserves rate and yield of single well. When the pressure of production wells spread to neighboring distal production wells, injection wells will be part of the production of CO2, forming a rectangle of five wells net, CO2 flooding, establish effective displacement pressure system, supplement the formation energy, to ensure long-term stable production of tight oil wells.
The integrated technology of CO2 waterless fracturing has been used in ten tight oil wells of the north Oilfield in China. During the fracturing. In this treatment 19.8 m3 of proppant and 653.5m3 of liquid CO2 is used. As a result, the production has increased by over 100%. With low viscosity and high diffusion coefficient, supercritical CO2 is good for improving fracturing volume.
In the tight oil reservoir, The realization of artificial energy development, reducing carbon emissions, to further enhance oil recovery, improve the reservoir producing ability. At the same time, to realize large-scale CO2 sequestration and reduce carbon emissions, both realistic and economic, but also great social benefits.
Weng, Yibin (State Key Laboratory of Petroleum Pollution Control, China National Petroleum Corporation Research Institute of Safety and Environmental Technology) | Xue, Ming (State Key Laboratory of Petroleum Pollution Control, China National Petroleum Corporation Research Institute of Safety and Environmental Technology) | Cui, Xiangyu (State Key Laboratory of Petroleum Pollution Control, China National Petroleum Corporation Research Institute of Safety and Environmental Technology)
Summary Reducing greenhouse–gas (GHG) emissions in oil and gas production could provide several benefits, including energy conservation, cost reduction, and economic returns. The direct–emissions measurements and reduction–potential evaluation are the prerequisites to achieve an effective reduction goal in GHG emissions. On the basis of the survey of production processes and related parameters, we identified and measured a series of GHG–emissions sources. The emissions sources were measured, including production processes and leakage–prone facilities such as dehydrators, boilers, heaters, associated gas–treatment plants, light–hydrocarbon–recovery units, storage tanks, and gas flaring. A series of leakage–detection/measurement instruments was applied as well, such as flow samplers, impeller flowmeter, gas detectors, and gas–flow probes. On the basis of the measured emissions data, we then used a simulation model to evaluate the specific forms, sources, and reduction potentials of the GHGs. The measured GHG emissions showed that evaporation and flashing losses from storage tanks were the largest source, accounting for 86% of the total methane (CH4) emissions and 42% of the total GHG emissions. The contribution of CH4 emissions from heaters and boilers during incomplete combustions was less than 1% of the total CH4 emissions and approximately 16% of the total GHG emissions. When controlling technology on storage–tank losses was applied, CH4 emissions could be reduced by 81.7% and the GHG emissions could be reduced by 39.9%. Furthermore, such controlling technologies also presented substantial economic benefits through the recovery of fuel gas. In this study, the recovery potentials of various GHG–emissions sources were analyzed. In addition, a preliminary cost/benefit analysis was performed per the emissions categories, reduction potentials, and the feasibility of reduction technologies. Finally, the probability of the application of such reduction technologies was evaluated.
Mu, Lingyu (China University of Petroleum (Beijing)) | Liao, Xinwei (China University of Petroleum (Beijing)) | Zhang, Jingtian (CNPC Engineering Technology R&D Company Limited) | Liu, Guoguang (PetroChina Changqing Oilfield Company) | Jiang, Chenshuo (College of Textile and Clothing of Xinjiang University) | Zou, Jiandong (China University of Petroleum (Beijing)) | Li, Rongtao (China University of Petroleum (Beijing))
Deep saline aquifer is deemed as an effective and promising site for carbon sequestration. A geological storage site must be operated safely; however, CO2 may leak through several pathways, such as fractures, faults and/or improperly plugged wells.
This study presents a new analytical model predicting the pressure change in the monitoring well and the leakage rate, caused by an inclined fracture in the caprock, to detect and evaluate the leakage. Distinct with previous analytical method, herein we propose a new case of the leakage through the inclined fracture in a closed aquifer system, which expands on earlier work to a wider application. The solutions for the injection at a constant rate and the time-dependent leakage through an inclined fracture of caprock are derived with Laplace transform, Fourier cosine transform and Duhamel’s principle. Then, by means of the superposition method, the pressure change and the leakage rate with both of the two processes are determined in succession. Based on the above solutions, we discuss the effect of the leakage path and the boundary of the aquifer on the system.
At the early stage, the leakage rate increases more rapidly with the smaller radius of the aquifer. Moreover, in the smaller aquifer, the rapid pressure transient results in that the system quickly reach the stable stage. The effect of the inclined fracture on the system is embodied in its permeability, location and angle. With higher permeability the leakage rate increases more quickly at early stage and reaches the constant value more quickly at late‐time stable stage. The fracture has slight impact on the leakage in the long term. Location of fracture does not affect the leakage rate at rapid increase stage. Leakage rate is larger and increases with smaller distance at transitional stage. With the increase of angle, leakage rate increases at all three stages. At the late‐time stage, the larger the angle is, the larger the leakage rate is.
Nguyen, Minh C. (University of Wyoming, Laramie / Los Alamos National Laboratory) | Zhang, Liwei (Chinese Academy of Sciences, Wuhan) | Wei, Ning (Chinese Academy of Sciences, Wuhan) | Li, Xiaochun (Chinese Academy of Sciences, Wuhan) | Zhang, Ye (University of Wyoming, Laramie) | Stauffer, Philip H. (Los Alamos National Laboratory)
ABSTRACT Saline aquifers, among other potential CO2 storage formations, have been proven to offer the highest storage capacity necessary for commercial-scale carbon capture and storage (CCS) projects. They are an ideal target for emission reduction from coal-fired power plants in the sourcesink model. However, unlike hydrocarbon reservoirs which are typically well developed, these deep formations face the challenge of characterization due to a lack of data and their uncertainty. Spatial reservoir information is critical in understanding CO2 injectivity, plume dynamics, and pressure management during and after injection operations. In this study, we combine geologic and dynamic data from the Shenhua CCS Demonstration Project in the Ordos Basin, China to provide an improved explanation for the pressure behavior and interesting injectivity at the site as well as presenting a risk assessment study of long-term storage safety. We extend the work of Nguyen et al. (2017a, b) in that a system of interconnected meandering channels are incorporated into our geologic model to account for the pore volume needed to allow high injectivity. CO2 injection simulations are carried out by varying geologic and rock/fluid parameters to generate scenarios that offer a better understanding of the subsurface spatial heterogeneity which contributed to our observed behavior. Simulation results suggest that the lateral extent of conceptual fluvial channels may not be as extensive as previously thought since the pressure front travels faster than our CO2 plume, resulting in minimal pressure buildup at the bottom-hole level. Our study also finds that the injection well may have penetrated a sandbody with interconnected permeability which contradicts the notion in previous work that a high permeability area to the Northwest of the injection well may be the cause of low-pressure buildup. Injection rate allocation is an important parameter in explaining the bottom-hole pressure (BHP) response at the injection well. Our models also provide a range of scenarios with the target 300,000 tons of CO2 being successfully injected into 5 layers of saline aquifers, with the sandstone Liujiagou formation receiving most of the injection. Risk assessment based on these scenarios honoring historical injection data suggests that there is a low probability of CO2/brine leakage through legacy wellbores in the area, including the injection and two monitoring wells.
In this paper, based on the correlation between meteorological factors and sea ice area from 1958 to 2015, we study sea ice area change and its driving factors. The results show that the maximum and average of sea ice area showed a downward trend, with annual change rates of −0.33±0.18% and −0.51±0.16%, respectively. The whole period can be divided into slight growth (1958-1980), significant decline (1980-1995) and moderate growth (1995-2015). The temperature change rate during the ice melting period is much larger than the freezing ice period. Based on the relationship between sea ice area and temperature, this paper studies the change of sea ice area and the driving effect of temperature.
The cryosphere is highly sensitive to climate change. This has been confirmed by the reduction of polar ice sheets and the shrinkage of mountain glaciers in recent years (Qin Dahe, 2014). As one of the important components of the cryosphere, sea ice will also be a clear response to climate change (Rui Ruibo, 2008; Liu et al., 2013). For seasonal sea ice (Barron Sea (Årthun et al., 2012), Baltic Sea (Karpechko, 2015), the Sea of Khoik (Paik, 2017), and the Bohai, etc., their responses to climate change not only reflects the interaction between sea and air, but also the indication of coastal climate change, and also involves sea ice in coastal areas and relates to disaster prevention and mitigation. Bohai Sea region is a critical economic zone in China. Winter sea ice poses a serious threat to human economic activities such as offshore oil exploration, marine transportation, aquaculture, and offshore engineering construction, especially in severe ice conditions. Closely monitoring the sea ice conditions and their variability in this region is impotant for ice disaster prevention and climate change studies (Ji, 2011; Sun, 2012; Xu, 2015),
Accurately grasping the characteristics of ice changes in the seasonal sea ice of the Bohai Sea is a key link to study its response to global climate change, indications of coastal climate change, and strategies for assessing sea ice hazard risk. At that time, in order to express the degree of ice in the entire Bohai Sea area, the ice level index was established, and it was used as a reference for analyzing the changes of large-scale ice conditions by point and area (Ding, 1999). And remote sensing technology has become the main means of sea ice monitoring. Many scholars use remote sensing data to invert sea ice area (Comiso, 2008; Notz, 2016), making it possible to obtain large-scale sea ice area data that was difficult to obtain in the past. However, remote sensing data, especially optical satellite images, are easily affected by the cloud, and the available images are relatively low. Therefore, the use of remote sensing data to invert daily sea ice area has many problems such as missing data and the time series is not long enough (Cavalieri, 1999). Yan, 2017).
This paper examines the effect of including a tuna aquaculture component to a proposed integrated system utilizing ocean energy and microalgae to produce biofuel. Cost-benefit analysis and carbon footprint estimation show a significant improvement on both economic and environmental performance of the system. The results suggest that climate change mitigation activities in ocean area should take biological resources into account rather than concentrate on energy products.
Climate change is one of the top concerns related to the sustainability of human society. The IPCC reports called for all kinds of activities for mitigating the global warming in order to avoid serious impacts on natural system. However, the contributions from the anthropogenic activities in ocean area, despite it covers over 70% of the earth surface, were less important in almost all of the future scenario analysis (IPCC, 2014).
The typical climate mitigation option of the activities in ocean area is the utilization of ocean energy including offshore wind, ocean thermal energy conversion, wave energy, current energy and tidal energy. Conventionally, electricity is to be generated using the ocean energy, then transmitted onshore or converted to other energy carriers and delivered onshore. As the result, the cost of energy product from ocean including production cost and transportation cost is usually higher than that of the same kind of product produced on land area (IEA OES, 2015). This higher cost limits the large scale application of the ocean energy utilization. Thus, in order to provide larger contribution to climate change mitigation, some concepts have been proposed to improve the economic performance through integrating other economic activities to the ocean energy development.
Meanwhile, an increasing request of the ocean development was generated by maintaining sustainable economic growth due to limited land-based resources during the past decades. Various applications to produce food, water and other necessary products were carried out mainly in coastal area for a long period. However, these applications together with the activities in river drainage basins have caused serious degradation of the ocean environment and the marine ecosystem. To avoid this limitation, the proposed concepts concentrated on offshore utilization systems.