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101.
102.
CO2 saturations are estimated at Sleipner using a two-step imaging workflow. The workflow combines seismic tomography (full-waveform inversion) and rock physics inversion and is applied to a two-dimensional seismic line located near the injection point at Sleipner. We use baseline data (1994 vintage, before CO2 injection) and monitor data that was acquired after 12 years of CO2 injection (2008 vintage). P-wave velocity models are generated using the Full waveform inversion technology and then, we invert selected rock physics parameters using an rock physics inversion methodology. Full waveform inversion provides high-resolution P-wave velocity models both for baseline and monitor data. The physical relations between rock physics properties and acoustic wave velocities in the Utsira unconsolidated sandstone (reservoir formation) are defined using a dynamic rock physics model based on well-known Biot–Gassmann theories. For data prior to injection, rock frame properties (porosity, bulk and shear dry moduli) are estimated using rock physics inversion that allows deriving physically consistent properties with related uncertainty. We show that the uncertainty related to limited input data (only P-wave velocity) is not an issue because the mean values of parameters are correct. These rock frame properties are then used as a priori constraint in the monitor case. For monitor data, the Full waveform inversion results show nicely resolved thin layers of CO2–brine saturated sandstones under intra-reservoir shale layers. The CO2 saturation estimation is carried out by plugging an effective fluid phase in the rock physics model. Calculating the effective fluid bulk modulus of the brine–CO2 mixture (using Brie equation in our study) is shown to be the key factor to link P-wave velocity to CO2 saturation. The inversion tests are done with several values of Brie/patchiness exponent and show that the CO2 saturation estimates are varying between 0.30 and 0.90 depending on the rock physics model and the location in the reservoir. The uncertainty in CO2 saturation estimation is usually lower than 0.20. When the patchiness exponent is considered as unknown, the inversion is less constrained and we end up with values of exponent varying between 5 and 20 and up to 33 in specific reservoir areas. These estimations tend to show that the CO2–brine mixing is between uniform and patchy mixing and variable throughout the reservoir. 相似文献
103.
Huang Sijing Li Xiaoning Wu Wenhui Zhang Meng Hu Zuowei Liu Sibing Huang Keke Zhong Yijiang 《地球科学进展》2015,30(11):1185-1197
Carbon isotopic composition of marine carbonates is a record for various important geological events in the process of earth development and evolution. The carbonates of Carboniferous, Permian and Triassic, as the transition from Paleozoic to Mesozoic-Cenozoic have very high 13C value. Taking this as the main point, and combined with the oxygen, strontium isotopic composition in carbonates, distribution of carbonate basin area through geologic time, the correlation of carbon isotopic composition of marine carbonates to sea level change, organic carbon burial flux, exchange of CO2 content in atmosphere and ocean, and long cycle evolution of the earth ecosystems were approached. The results are shown as follows: ①The interval of 13C >3‰ during Phanerozoic was concentrated in Carboniferous, Permian and the beginning of Triassic, but the beginning of Triassic was characterized by higher frequency and larger fluctuations in 13C value during a short time, whereas the Carboniferous-Permian presented a continuously stable high 13C value, indicating a larger amount of organic carbon accumulation in this time interval. Relatively high 18O values during this time was also observed, showing a long time of glaciations and cold climate, which suggest a connection among rapid organic carbon burial, cold climate, as well as pCO2 and pO2 states of atmosphere. ②The over consumption of atmosphere CO2 by green plants during the time with high 13C of seawater forced CO2 being transferred from ocean to atmosphere for the balance, but the decrease in the seawater amount and water column pressure caused by the global cooling could weaken dissolution capacity of CO2 in seawater and carbon storage of marine carbonates, and also reduce the carbonate sedimentary rate and decrease the carbonate basin area globally from Devonian to Carboniferous and Permian. During the middle-late Permian carbonate was widely replaced by siliceous sediments even though in shallow carbonate platform, which resulted in the decrease of marine invertebrates, suggesting the Permian chert event should be global. ③The Phanerozoic 87Sr/86Sr trend of seawater showed a sharp fall in Permian and drop to a minimum at the end of the Permian, indicting input of strontium from the submarine hydrothermal systems (mantle flux). Such process should accompany with a supplement of CO2 from deep earth to atmosphere and ocean system, but the process associated with widespread volcanism and rises of earth’s surface temperature pricked up the mass extinction during the time of end Permian. ④Cold climate and increase of continental icecap volume, the amalgamation of northern Africa and Laurentia continentals were the main reasons responsible for the sea level drop, but the water consumption result from the significantly increased accumulation of organic carbon should also be one of the reasons for the sea level drop on the order of tens of meters. ⑤The mass extinction at the end Permian was an inevitable event in the process of earth system adjustment. It was difficult for marine invertebrates to survive because of the continuously rapid burial of organic carbon, and of the decrease of sea water amount and its dissolution ability to CO2. At last, at the end of Paleozoic, the supplement of CO2 to atmosphere and ocean by widely magma activities resulted in a high temperature of earth surface and intensified mass extinction. 相似文献
104.
美国RD公司声学多普勒流速剖面仪(ADCP)使用的波向估计算法是迭代的最大似然算法(IMLM),IMLM可以准确估计出主浪向,但波向估计结果在主浪向以外其他方向上存在由噪声带来的能量分布,使得估计结果变得不准确。设计了基于COS-2S模型的波向估计方法,模型中只含有主波向,算法在准确估计主波向同时有效去除其他方向上噪声带来的能量分布。将一种混合遗传算法(HGA)代替遗传算法(GA)应用到波浪模型的参数求解中,HGA相对GA收敛更快,可有效找出全局最优解。仿真分析和实测数据表明,HGA和IMLM都能准确估计出波浪的主浪向,但HGA可有效去除主浪向以外其他方向上噪声带来的能量分布,HGA比IMLM更加适用于海洋各种噪声存在条件下的测量环境。 相似文献
105.
为研究青蛤(Cyclina sinensis)对重金属Cu~(2+)的蓄积作用及免疫机能的影响,开展了Cu~(2+)对青蛤的急性毒性实验,观察青蛤在96 h Cu~(2+)半致死浓度和安全浓度胁迫下,不同组织的蓄积趋势,及血淋巴液中SOD、CAT和ACP活性的变化。结果显示:Cu~(2+)的半致死浓度为0.807 mg/L,安全浓度为0.00807 mg/L。鳃和内脏团组织中蓄积的Cu~(2+)浓度与处理时间呈正相关;在半致死和安全浓度胁迫下,鳃组织中Cu~(2+)蓄积速度均快于内脏团;在半致死浓度胁迫下血淋巴液中SOD、CAT和ACP活性呈现先诱导再抑制的趋势,安全浓度下无明显变化,但均高于对照组水平。 相似文献
106.
Kamaljit Singh Rajkumar Megha Maheshwari Jayaprasad Pallipad Dhani Ram Rajak Raj Kumar 《Marine Geodesy》2015,38(3):497-509
Radar altimetry provides an important geophysical parameter, backscatter coefficient (σ0), which is useful in studying target surface characteristics. Ku-band (Oceansat-2 scatterometer- OSCAT) and Ka-band (SARAL-AltiKa altimeter) data are concurrently used to characterize polar surface features over the Antarctic region. Maximum-likelihood classification has been employed to classify combined data set (AltiKa and OSCAT) for discrimination among sea ice, open water, and ice sheet (interior and exterior). The sea ice region obtained using the current approach has been compared with sea ice boundary derived from passive microwave data. 相似文献
107.
海表面二氧化碳分压(pCO2)的未来变化趋势,对统计评估全球碳收支以及理解全球气候变化背景下的海洋酸化现象至关重要。目前传统的海面pCO2预测方法大部分基于有限的实测数据,然而实测数据存在着时间和地理方面的制约,且计算成本较高。近年来,随着时空观测数据的爆炸性增长,基于深度学习的数据驱动模型在海表面pCO2预测方面中表现出良好的潜力。然而,由于多种环境因素与海表面pCO2之间的关系错综复杂,到目前为止尚无十分简单有效的相关模型来对海表面pCO2进行预测。为应对这一挑战,利用时空卷积长短时记忆神经网络(ST-ConvLSTM)模型,通过海面温度(sea surface temperature, SST)、海面盐度(sea surface salinity, SSS)、叶绿素a浓度(chl a)和海面pCO2数据,预测南海的海面pCO2,并将2019年1~12月的数据作为测试集对模型的表现进行了验证。结果显示, ST-ConvLSTM模型... 相似文献
108.
Churyumov Klim I. Luk'yanyk Igor V. Berezhnoi Alexei A. Chavushyan Vahram H. Sandoval Lourdes S. Palma Alejandro A. 《Earth, Moon, and Planets》2002,90(1-4):361-368
We present a preliminary analysis of medium resolution optical spectra of comet C/2000 WM1 (LINEAR) obtained on 22 November
2001. Theemission lines of the molecules C2, C3, CN, NH2,H2O+ and presumably CO (Asundi and triplet bands) and C2
-were identified in these spectra. By analysing the brightnessdistributions of the C2, C3, CN emission lines along theslit of the spectrograph we determined some physical parameters of theseneutrals, such as their
lifetimes and expansion velocities inthe coma. The Franck–Condon factors for the CO Asundi bands and C2
- bands were calculated using a Morse potential model. 相似文献
109.
110.
The Orbital Evolution of Two Sounding Satellites and Analysis of the Accuracy of Orbit Determination
Gong-you Wu Chang-yin Zhao Rong-zhi Zhang Jia-song Wang Hong-bo Wang 《Chinese Astronomy and Astrophysics》2007,31(4):420-429
The satellites TC-1 and TC-2 are the two Chinese satellites with great elliptical orbits which are still in orbit around the earth at present. Since the launch the orbits of the two satellites have continuously evolved, which has a certain effect on the orbit determination and prediction precision. The regularities of the orbital evolution of the two sounding satellites are qualitatively and quantitatively analyzed. Under the current tracking mode the corresponding prediction precision of orbit determination is analyzed based on the different stages of the orbital evolution, thereby providing the basis for the adjustment of planning mode by the satellite application departments and the guarantee of normal satellite payload. Finally, the orbital lifetimes of the two satellites are predicted through the trend of the orbital evolution. 相似文献